Strategic HIV Case Findings among Infants at Different Entry Points of Health Facilities in Cameroon: Optimizing the Elimination of Mother-To-Child Transmission in Low- and- Middle-Income Countries.

BACKGROUND: HIV case finding is an essential component for ending AIDS, but there is limited evidence on the effectiveness of such a strategy in the pediatric population. We sought to determine HIV positivity rates among children according to entry points in Cameroon. METHODS: A facility-based survey was conducted from January 2015 to December 2019 among mother-child couples at various entry points of health facilities in six regions of Cameroon. A questionnaire was administered to parents/guardians. Children were tested by polymerase chain reaction (PCR). Positivity rates were compared between entry points. Associations were quantified using the unadjusted positivity ratio (PR) for univariate analyses and the adjusted positivity ratio (aPR) for multiple Poisson regression analyses with 95% confidence intervals (CIs). p-values < 0.05 were considered significant. RESULTS: Overall, 24,097 children were enrolled. Among them, 75.91% were tested through the HIV prevention of mother-to-child transmission (PMTCT) program, followed by outpatient (13.27%) and immunization (6.27%) services. In total, PMTCT, immunization, and outpatient services accounted for 95.39% of children. The overall positivity was 5.71%, with significant differences (p < 0.001) between entry points. Univariate analysis showed that inpatient service (PR = 1.45; 95% CI: [1.08, 1.94]; p = 0.014), infant welfare (PR = 0.43; 95% CI: [0.28, 0.66]; p < 0.001), immunization (PR = 0.56; 95% CI: [0.45, 0.70]; p < 0.001), and PMTCT (PR = 0.41; 95% CI: [0.37, 0.46]; p < 0.001) were associated with HIV transmission. After adjusting for other covariates, only PMTCT was associated with transmission (aPR = 0.66; 95% CI: [0.51, 0.86]; p = 0.002). CONCLUSIONS: While PMTCT accounts for most tested children, high HIV positivity rates were found among children presenting at inpatient, nutrition, and outpatient services and HIV care units. Thus, systematic HIV testing should be proposed for all sick children presenting at the hospital who have escaped the PMTCT cascade.

Determinants of Immunovirological Response among Children and Adolescents Living with HIV-1 in the Central Region of Cameroon.

About 90% of new HIV-1 infections in children occur in sub-Saharan Africa, where treatment monitoring remains suboptimal. We sought to ascertain factors associated with immunovirological responses among an ART-experienced paediatric population in Cameroon. A laboratory-based and analytical study was conducted from January 2017 throughout December 2020 wherein plasma viral load (PVL) analyses and CD4 cell counts were performed. Viral suppression (VS) was defined as PVL < 1000 copies/mL and immunological failure (IF) as CD4 < 500 cells/µL for participants ≤5 years and CD4 < 250 cells/µL for those >5 years; p < 0.05 was considered statistically significant. Overall, 272 participants were enrolled (median age: 13 [9-15.5] years; 54% males); median ART duration 7 [3-10] years. Globally, VS was achieved in 54.41%. VS was 56.96% in urban versus 40.48% in rural areas (p = 0.04). IF was 22.43%, with 15.79% among participants ≤5 years and 22.92% among those >5 years (p = 0.66). IF was 20.43% in urban versus 33.33% in rural areas (p = 0.10). Following ART, IF was 25.82% on first-line (non-nucleoside reverse transcriptase inhibitors; NNRTI-based) versus 10.17% on second-line (protease inhibitor-based) regimens (p = 0.01). Interestingly, IF was 7.43% among virally suppressed versus 40.32% among virally unsuppressed participants (p < 0.0001). A low VS indicates major challenges in achieving AIDS' elimination in this paediatric population, especially in rural settings and poor immune statuses. Scaling up NNRTI-sparing regimens alongside close monitoring would ensure optimal therapeutic outcomes.

Characterization of HIV-1 Reservoirs in Children and Adolescents: A Systematic Review and Meta-Analysis Toward Pediatric HIV Cure.

OBJECTIVE: To conduct a comprehensive, systematic review of the profile of HIV-1 reservoirs in children and adolescents with perinatally acquired HIV infection. STUDY DESIGN: Randomized and nonrandomized trials, cohort studies, and cross-sectional studies on HIV reservoirs in pediatric populations, published between 2002 and 2022, were included. Archived-drug resistance mutations (ADRMs) and the size of reservoirs were evaluated. Subgroup analyses were performed to characterize further the data, and the meta-analysis was done through random effect models. RESULTS: Overall, 49 studies from 17 countries worldwide were included, encompassing 2356 perinatally infected participants (48.83% females). There are limited data on the quantitative characterization of viral reservoirs in sub-Saharan Africa, with sensitive methodologies such as droplet digital polymerase chain reaction rarely employed. The overall prevalence of ADRMs was 37.80% (95% CI 13.89-65.17), with 48.79% (95% CI 0-100) in Africa, 42.08% (95% CI 6.68-82.71) in America, 23.88% (95% CI 14.34-34.90) in Asia, and 20.00% (95% CI 10.72-31.17) in Europe, without any difference between infants and adolescents (P = .656). Starting antiretroviral therapy (ART) before 2 months of age limited the levels of HIV-1 DNA (P = .054). Participants with long-suppressed viremia (>5 years) had lower levels of HIV-1 DNA (P = .027). Pre- and post-ART CD4 ≤29% and pre-ART viremia ≥5Log were all found associated with greater levels of HIV-1 DNA (P = .038, P = .047, and P = .041, respectively). CONCLUSIONS: The pooled prevalence of ADRMs is high in perinatally infected pediatric population, with larger proviral reservoir size driven by delayed ART initiation, a shorter period of viral suppression, and immunovirological failures. Thus, strategies for pediatric HIV functional cure should target children and adolescents with very early ART initiation, immunocompetence, and long-term viral suppression.

Dynamics and durability of HIV-1 neutralization are determined by viral replication.

Human immunodeficiency virus type 1 (HIV-1)-neutralizing antibodies (nAbs) that prevent infection are the main goal of HIV vaccine discovery. But as no nAb-eliciting vaccines are yet available, only data from HIV-1 neutralizers-persons with HIV-1 who naturally develop broad and potent nAbs-can inform about the dynamics and durability of nAb responses in humans, knowledge which is crucial for the design of future HIV-1 vaccine regimens. To address this, we assessed HIV-1-neutralizing immunoglobulin G (IgG) from 2,354 persons with HIV-1 on or off antiretroviral therapy (ART). Infection with non-clade B viruses, CD4+ T cell counts <200 µl-1, being off ART and a longer time off ART were independent predictors of a more potent and broad neutralization. In longitudinal analyses, we found nAb half-lives of 9.3 and 16.9 years in individuals with no- or low-level viremia, respectively, and 4.0 years in persons who newly initiated ART. Finally, in a potent HIV-1 neutralizer, we identified lower fractions of serum nAbs and of nAb-encoding memory B cells after ART initiation, suggesting that a decreasing neutralizing serum activity after antigen withdrawal is due to lower levels of nAbs. These results collectively show that HIV-1-neutralizing responses can persist for several years, even at low antigen levels, suggesting that an HIV-1 vaccine may elicit a durable nAb response.

Characterisation of HIV-1 reservoirs in paediatric populations: protocol for a systematic review and meta-analysis.

INTRODUCTION: The success of antiretroviral therapy (ART) has changed HIV from a deadly to a chronic infection, thus increasing the transitioning from infancy toward adulthood. However, the virostatic nature of antiretrovirals maintains viruses in sanctuaries, with reactivation potentials. Because current ARTs are very limited for children, the emergence of new HIV epidemics driven by HIV drug-resistance mutations is favoured. Our systematic review aims to estimate the global burden of archived drug-resistance mutations (ADRMs) and the size of reservoir (HIV-1 DNA load), and their associated factors in children and adolescents. METHODS AND ANALYSIS: Papers from the PubMed/MEDLINE, Google Scholar, ScienceDirect, African Journals Online and Academic Medical Education Databases will be systematically identified using the keywords: "HIV-1 reservoirs", "viral reservoirs", "HIV-1 DNA", infants, adolescents, child and children, linked by the following Boolean operators: 'OR' and 'AND'. Randomised and non-randomised trials, cohort studies and cross-sectional studies published in French or English from January 2002 will be included, while case reports, letters, comments, reviews, systematic reviews and meta-analyses, and editorials will be excluded. All studies describing data on ADRMs, HIV-1 DNA load and/or immunological markers among children/adolescents will be eligible. A random-effects model will be used to calculate the pooled prevalence of ADRMs. Data will be reported according to type of viral reservoir (peripheral blood mononuclear cells, CD4 cells), geographical location (country/continent), ethnicity/race, age (infants vs adolescents), gender, HIV-1 clades, ART exposure (naïve vs treated, drug class, type of regimen, age at ART initiation and treatment duration), WHO clinical staging (I, II, III, IV), immune status (immune compromised vs immune competent) and virological response (viraemic vs non-viraemic). Multivariate logistic regression will be performed to determine predictors of HIV reservoir profile in paediatric populations. The primary outcome will be to assess the genotypical and quantitative profile of HIV reservoirs, while the secondary outcomes will be to identify factors associated with ADRMs and reservoir size in paediatric populations. ETHICS AND DISSEMINATION: Ethical approval is not applicable for this study as it will be based on published data. Results will be disseminated via a peer-reviewed scientific journal and relevant conferences. PROSPERO REGISTRATION NUMBER: CRD42022327625.

Inflammatory profile of vertically HIV-1 infected adolescents receiving ART in Cameroon: a contribution toward optimal pediatric HIV control strategies.

Antiretroviral therapy (ART) has improved the lifespan of people living with HIV. However, their immune system remains in a state of sustained activation/inflammation, which favors viral replication and depletion of helper T-cells with varying profiles according to ART-response. We herein sought to ascertain the inflammatory profile of adolescents living with perinatal HIV-1 infection (ALPHI) receiving ART in an African context. In this cross-sectional and comparative study among ART-experienced ALPHI in Yaoundé-Cameroon, HIV-1 RNA was measured by Abbott Real-time PCR; CD4 cells were enumerated using flow cytometry; serum cytokines were measured by ELISA; HIV-1 proviral DNA was genotyped by Sanger-sequencing; and archived drug resistance mutations (ADRMs) were interpreted using Stanford HIVdb.v9.0.1. Overall, 73 adolescents were enrolled (60 ALPHI and 13 HIV-1 negative peers) aged 15 (13-18) years; 60.00% were female. ART median duration was 92 (46-123) months; median viral load was 3.99 (3.17-4.66) RNA Log10 (copies)/mL and median CD4 count was 326 (201-654) cells/mm3. As compared to HIV-negative adolescents, TNFα was highly expressed among ALPHI (p<0.01). Following a virological response, inflammatory cytokines (IFNγ and IL-12), anti-inflammatory cytokines (IL-4 and IL-10) and inflammation-related cytokines (IL-6 and IL-1ß) were highly expressed with viral suppression (VS) vs. virological failure (VF), while the chemokine CCL3 was highly expressed with VF (p<0.01). Regarding the immune response, the inflammatory cytokine TNFα was highly expressed in those that are immunocompetent (CD4≥500 cell/mm3) vs. immunocompromised (CD4<500 cell/mm3), p ≤ 0.01; while chemokine CCL2 was highly expressed in the immunocompromised (p<0.05). In the presence of ADRMs, IL-4 and CCL3 were highly expressed (p=0.027 and p=0.043 respectively). Among ART-experienced ALPHI in Cameroon, the TNFα cytokine was found to be an inflammatory marker of HIV infection; IFNγ, IL-1ß, IL-6, and IL-12 are potential immunological markers of VS and targeting these cytokines in addition to antiretroviral drugs may improve management. Moreover, CCL3 and CCL2 are possible predictors of VF and/or being immunocompromised and could serve as surrogates of poor ART response.

Challenges faced by the HIV testing system in low- and middle-income countries.

Introduction: Determining the HIV status of some individuals remains challenging due to multidimensional factors such as flaws in diagnostic systems, technological challenges, and viral diversity. This report pinpoints challenges faced by the HIV testing system in Cameroon. Case presentation: A 53-year-old male received a positive HIV result by a rapid testing algorithm in July 2016. Not convinced of his HIV status, he requested additional tests. In February 2017, he received a positive result using ImmunoComb® II HIV 1 & 2 BiSpot and Roche cobas electrochemiluminescence assays. A sample sent to France in April 2017 was positive on the Bio-Rad GenScreen™ HIV 1/2, but serotyping was indeterminate, and viral load was < 20 copies/mL. The Roche electrochemiluminescence immunoassay and INNO-LIA HIV I/II Score were negative for samples collected in 2018. A sample collected in July 2019 and tested with VIDAS® HIV Duo Ultra enzyme-linked fluorescent assay and Geenius™ HIV 1/2 Confirmatory Assay was positive, but negative with Western blot; CD4 count was 1380 cells/mm3 and HIV proviral DNA tested in France was 'target-not-detected'. Some rapid tests were still positive in 2020 and 2021. Serotyping remained indeterminate, and viral load was 'target-not-detected'. There were no self-reported exposure to HIV risk factors, and his wife was HIV-seronegative. Management and outcome: Given that the patient remained asymptomatic with no evidence of viral replication, no antiretroviral therapy was initiated. Conclusion: This case highlights the struggles faced by some individuals in confirming their HIV status and the need to update existing technologies and develop an algorithm for managing exceptional cases.

Evaluation of archived drug resistance mutations in HIV-1 DNA among vertically infected adolescents under antiretroviral treatment in Cameroon: Findings during the COVID-19 pandemic.

BACKGROUND: With the success of antiretroviral therapy (ART), children born with HIV are more likely to reach adolescence. However, frequent non-adherence to ART in adolescents living with HIV (ALHIV) leads to viral replication. Notably, a viraemic infection might lead to archived drug resistance mutations (ADRMs). Hence, within the context of the COVID-19 pandemic, we aimed to compare the patterns of ADRMs in viraemic and non-viraemic vertically infected ALHIV and to assess their immunity to and diagnosis of SARS-CoV-2. METHODS: A comparative study was conducted among COVID-19-unvaccinated ALHIV receiving ART in Yaoundé-Cameroon over the period October 2021 to March 2022. Plasma HIV-RNA was measured using Abbott® m2000rt; HIV-1 genotyping was performed on buffy-coat (HIV-1 DNA) and ADRMs were interpreted using HIVdb.v9.0.1. Patterns of HIV-1 ADRMs were compared between viraemic (≥ 1.60 log10 HIV-1 RNA copies/ml) and non-viraemic (< 1.60 log10 copies/ml) individuals. SARS-CoV-2 antibodies were assessed on whole blood using Abbott Panbio COVID-19 immunoglobulin G/M (IgG/IgM) rapid test and COVID-19 polymerase chain reaction test was performed using nasopharyngeal swab samples. RESULTS: Of the 60 ALHIV [aged 17 (16-19) years, 51.6% female], median ART duration was 14 (12-16) years; 31/55 (56.3%) were exposed to nonnucleoside reverse transcriptase inhibitor (NNRTI)-based first-line ART (of whom 19/31 transitioned to dolutegravir-based ART in 2020) and 24/55 (43.6%) were on second-line ART. Forty-two out of 60 (70.0%) ALHIV were non-viraemic; 43/60 (71.6%) were successfully sequenced. Overall the ADRM rate was 62.7% (27/43), with 69.2% (9/13) viraemic and 60.0% (18/30) non-viraemic (p = 0.56). NNRTI-ADRMs were significantly higher among viraemic ALHIV (69.2% vs. 46.7%, p = 0.030). Regarding immunity, those with CD4 nadir < 350 cells/µl had significantly higher rates of ADRMs [adjusted odds ratio (aOR) = 3.20 (1.36-95.53), p = 0.03]. In relation to COVID-19 immunity, overall SARS-CoV-2 IgG seropositivity was 28.3% (17/60), whereas 0% (0/60) were seropositive to IgM; in particular, those with CD4 count nadir ≥ 350 cells/µl had higher odds of SARS-CoV-2 IgG seropositivity [OR =7.85 (2.03-30.28), p < 0.01]. No significant association was found between SARS-CoV-2 IgG seropositivity and HIV-RNA (non-viraemic, 33.3%; viraemic, 16.7%; p = 0.18). SARS-CoV-2 RNA prevalence was 4.5% (2/44). The two positive participants were with low-levels of viral load (Ct > 30) and seropositive to IgG. CONCLUSION: In the context of virological success, the majority of ALHIV harbour ADRMs, essentially driven by NNRTI mutations and low CD4 nadir. During the current pandemic, about one-third of ALHIV were previously exposed to SARS-CoV-2. However, some children might have been exposed and uninfected and others might have been infected but showed no serological response at sampling. These findings support the use of NNRTI-sparing regimens and the implementation of COVID-19 barrier measures targeting ALHIV during such a pandemic.

The mother-to-child transmission of HIV-1 and profile of viral reservoirs in pediatric population: A systematic review with meta-analysis of the Cameroonian studies.

BACKGROUND: The mother-to-child transmission of HIV-1 (MTCT) remains on the major route of HIV-transmission among pediatric populations in Africa. Though a prevention of MTCT (PMTCT) high-priority country, data on the MTCT burdens in Cameroon remains fragmented. OBJECTIVE: We sought to assess the pooled MTCT rate, its risk-factors, and to characterize viral reservoirs of infected-children in Cameroon. METHODS: All relevant observational cohort and cross-sectional studies conducted in Cameroon were searched from PubMed, African Journals Online, Google scholar, ScienceDirect and academic medical education databases. Heterogeneity and publication bias were respectively assessed by the I2 statistic and the Egger/funnel plot test. Meta-analysis was performed using the random effects model. MTCT rate >5% was considered as "high". This review was registered in the Prospero database, CRD42021224497. RESULTS: We included a total of 29 studies and analyzed 46 684 children born from HIV-positive mothers. The overall rate of MTCT was 7.00% (95% CI = 6.07-8.51). According to regions, the highest burden was in Adamaoua-region (17.51% [95% CI:14.21-21.07]) with only one study found. PMTCT option-B+ resulted in about 25% reduction of MTCT (8.97% [95% CI: 8.71-9.24] without option-B+ versus 2.88% [95% CI: 5.03-9.34] with option-B+). Regarding risk-factors, MTCT was significantly associated with the absence of PMTCT-interventions both in children (OR:5.40 [95% CI: 2.58-11.27]) and mothers (OR: 3.59 [95% CI: 2.15-5.99]). Regarding viral reservoirs, a pro-viral DNA mean of 3.34±1.05 log10/mL was observed among 5/57 children and archived HIV drug resistance mutations were identified in pro-viral DNA marker among 21/79 infected-children. CONCLUSION: In spite of the dropdown in MTCT following option-B+ implementation, MTCT remains high in Cameroon, with substantial disparities across regions. Thus, in this era of option-B+, achieving MTCT elimination requires interventions in northern-Cameroon. The variation in pro-viral load in infected-children underlines the relevance of characterizing viral reservoirs for possible infection control in tropical settings.

Protection level of anti-hepatitis B vaccine and immunoglobulin in a pediatric Cameroonian population.

Despite the availability for nearly twenty years of an effective vaccine, hepatitis B remains one of the most frequent viral diseases throughout the world. Mother-to-child transmission is one of the primary routes of transmission in children. To assess the vaccine response in children born to HBV infected mothers. HBsAg-positive consenting mothers registered in the antenatal care (ANC) service database of Centre Hospitalier Dominicain St-Martin de Porres, Yaounde were enrolled with their children. Socio-demographic characteristics were collected using a tested questionnaire. The 5 markers of hepatitis B were tested and the quantification of anti-HBsAg antibodies was done by indirect ELISA method. The data collected was analyzed using Microsoft excel and Epi-info softwares. Out of 5,996 women registered, 143 were identified as HBsAg positive (2.38% prevalence) and none was HBeAg positive. Of these 143 HBsAg positive women, 50 were enrolled in the study. Of the 50 positive mothers, 78 children were included with a mean age ± standard deviation of 2.33±2.86 years. No child was infected with HBV, but all have been exposed to the virus (HBeAb-positive). Overall 64 (82.05%) received at birth both anti-HBs immunoglobulin (HBIG) and a dose of vaccine, while 14 (17.95%) received only the birth dose of vaccine. 72 (92.31%) children received all three recommended doses of vaccine. Vaccine responders were 62.82% (above 10 IU/ml), while 37.18% of children were non-responders; representing a higher risk group if not boosted. The coverage of the anti-HBV vaccine in children in this study was 92.31%. The protection level of 62.82% is below the 95% recommended rate by WHO. The factors sustaining this suboptimal protection should be investigated.

Characterization of the Viral Reservoirs Among HIV-1 Non-B Vertically Infected Adolescents Receiving Antiretroviral Therapy: Protocol for an Observational and Comparative Study in Cameroon.

BACKGROUND: Antiretroviral therapy (ART) can bring HIV-1 levels in blood plasma to the undetectable level and allow a near-normal life expectancy for HIV-infected individuals. Unfortunately, ART is not curative and must be taken for life, because within a few weeks of treatment cessation, HIV viremia rebounds in most patients except for rare elite or posttreatment controllers of viremia. The primary source of this rebound is the highly stable reservoir of latent yet replication-competent HIV-1 proviruses integrated into the genomic DNA of the resting memory cluster of differentiation 4 (CD4+) T cells. To achieve a cure for HIV, understanding the cell reservoir environment is of paramount importance. The size and nature of the viral reservoir might vary according to the timing of therapy, therapeutic response, ART duration, and immune response. The mechanisms of reservoir maintenance generally depend on the levels/type of immune recognition; in addition, the dynamics of viral persistence are different between pediatric and adult populations. This difference could become more evident as children grow toward adolescence. OBJECTIVE: We aim to characterize the HIV reservoirs and their variability as per the virological and immunological profiles of HIV-1 non-B vertically infected adolescents receiving ART in Cameroon during the Adolescents' Viral Reservoirs study to provide accurate and reliable data for HIV cure research. METHODS: This study will involve HIV-1 non-B vertically infected adolescents selected from an existing cohort in our institution. Blood samples will be collected for analyzing immunological/virological profiles, including CD4/CD8 count, plasma viral load, immune activation/inflammatory markers, genotyping, and quantification of HIV-1 viral reservoirs. We will equally recruit an age-matched group of HIV-negative adolescents as control for immunological profiling. RESULTS: This study received funding in November 2021 and was approved by the national institutional review board in December 2021. Sample collection will start in November 2022, and the study will last for 18 months. The HIV-1 sequences generated will provide information on the circulating HIV-1 subtypes to guide the selection of the most appropriate ART for the participants. The levels of immune biomarkers will help determine the immune profile and help identify factors driving persistent immune activation/inflammation in HIV-infected adolescents compared to those in HIV-uninfected adolescents. Analysis of the virological and immunological parameters in addition to the HIV-1 reservoir size will shed light on the characteristics of the viral reservoir in adolescents with HIV-1 non-B infection. CONCLUSIONS: Our findings will help in advancing the knowledge on HIV reservoirs, in terms of size and genetic variability in adolescents living with HIV. Such evidence will also help in understanding the effects of ART timing and duration on the size of the reservoirs among adolescents living with HIV-a unique population from whom the findings generated will largely contribute to designing functional cure strategies. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/41473.

Performance of immunochromatographic and immunoenzymatic techniques in the diagnosis of toxoplasmosis in pregnant women in Cameroon: need for harmonization.

Introduction: in order to contribute to the improvement of the management of toxoplasmosis in pregnant women in Cameroon, performance of two techniques commonly used in the diagnosis of toxoplasmosis was evaluated. Methods: a total of 541 pregnant women were recruited from seven hospitals in two Regions of Cameroon, of which 63% (341: Batch1) were from health facilities (HF) using a immunochromatographic technique (ICT) as a screening test for toxoplasmosis, and 37% (200: Batch2) from those using an immunoenzymatic technique (IEZ). On each sample, Ig (Immunoglobulin) G (IgG) and IgM were tested by three techniques: a Rapid Diagnostic Test (RDT), an Enzyme Linked Immuno Sorbent Assay (ELISA) and a Vidas Enzyme-linked fluorescent assay taken as reference (VIDAS/ELFA). The results from the health facilities were recorded. Results: for the IgG assay, our two laboratory methods were sensitive (96.0% and 97.5%) and specific (64.2% and 59.7%). Their concordance rates with the VIDAS/ELFA reference were above 60% (P<0.001). Moreover, for the IgM assay, the performances of the two methods were equivalent: Se= 18.2%, Sp= 99.4% with a low concordance rate (Kappa = 0.24). Considering the results provided by the selected hospitals, the ELISA used in Batch2 showed similar performances to the two techniques used in reference lab while the performances were low for the RDT used in Batch1. Conclusion: both methods showed similar performances (good for (IgG) and poor for IgM). However, for the immunochromatographic method, differences in performance were found between our results and those provided by the selected health facilities. These differences suggest a harmonization of diagnostic techniques for toxoplasmosis in pregnant women in Cameroonian health facilities.

The light chain of antibodies specific to the V2 region of HIV-1 can determine their function.

We studied the contribution of the light chain to functions of human monoclonal antibodies (mAbs) by measuring the relationships between the rate of mutations and cross-reactivity, binding affinity and neutralization activity. We analyzed 12 mAbs of two clonal families specific to the V2 region of HIV-1 derived from two chronically HIV-1 infected individuals. The clonal mAbs exhibited a range of reactivities, and the clones with superior properties were associated with the rate of mutations and the presence of particular mutated residues in the light chains, but not in the heavy chains. Our observations suggest that for some antibodies, the light chains play a vital role in antibody evolution toward more efficient ones and also suggest the importance of optimal residues rather than the rate of mutations in the variable fragment of the antibody.

Alteration of the gut fecal microbiome in children living with HIV on antiretroviral therapy in Yaounde, Cameroon.

Multiple factors, such as immune disruption, prophylactic co-trimoxazole, and antiretroviral therapy, may influence the structure and function of the gut microbiome of children infected with HIV from birth. In order to understand whether HIV infection altered gut microbiome and to relate changes in microbiome structure and function to immune status, virological response and pediatric ART regimens, we characterized the gut microbiome of 87 HIV-infected and 82 non-exposed HIV-negative children from Yaounde, a cosmopolitan city in Cameroon. We found that children living with HIV had significantly lower alpha diversity in their gut microbiome and altered beta diversity that may not be related to CD4+ T cell count or viral load. There was an increased level of Akkermansia and Faecalibacterium genera and decreased level of Escherichia and other Gamma proteobacteria in children infected with HIV, among other differences. We noted an effect of ethnicity/geography on observed gut microbiome composition and that children on ritonavir-boosted protease inhibitor (PI/r)-based ART had gut microbiome composition that diverged more from HIV-negative controls compared to those on non-nucleoside reverse-transcriptase inhibitors-based ART. Further studies investigating the role of this altered gut microbiome in increased disease susceptibility are warranted for individuals who acquired HIV via mother-to-child transmission.

Antiretroviral Imprints and Genomic Plasticity of HIV-1 pol in Non-clade B: Implications for Treatment.

Combinational antiretroviral therapy (cART) is the most effective tool to prevent and control HIV-1 infection without an effective vaccine. However, HIV-1 drug resistance mutations (DRMs) and naturally occurring polymorphisms (NOPs) can abrogate cART efficacy. Here, we aimed to characterize the HIV-1 pol mutation landscape in Cameroon, where highly diverse HIV clades circulate, and identify novel treatment-associated mutations that can potentially affect cART efficacy. More than 8,000 functional Cameroonian HIV-1 pol sequences from 1987 to 2020 were studied for DRMs and NOPs. Site-specific amino acid frequencies and quaternary structural features were determined and compared between periods before (≤2003) and after (2004-2020) regional implementation of cART. cART usage in Cameroon induced deep mutation imprints in reverse transcriptase (RT) and to a lower extent in protease (PR) and integrase (IN), according to their relative usage. In the predominant circulating recombinant form (CRF) 02_AG (CRF02_AG), 27 canonical DRMs and 29 NOPs significantly increased or decreased in RT during cART scale-up, whereas in IN, no DRM and only seven NOPs significantly changed. The profound genomic imprints and higher prevalence of DRMs in RT compared to PR and IN mirror the dominant use of reverse transcriptase inhibitors (RTIs) in sub-Saharan Africa and the predominantly integrase strand transfer inhibitor (InSTI)-naïve study population. Our results support the potential of InSTIs for antiretroviral treatment in Cameroon; however, close surveillance of IN mutations will be required to identify emerging resistance patterns, as observed in RT and PR. Population-wide genomic analyses help reveal the presence of selective pressures and viral adaptation processes to guide strategies to bypass resistance and reinstate effective treatment.

Evaluation of hepatic fibrosis in HIV/HCV co-infected individuals in Yaoundé, Cameroon: usefulness of APRI score in resource-constrained settings.

BACKGROUND: HIV infection exacerbates the prognosis of HCV infection, with a faster progression of hepatitis. Hepatic fibrosis is the major disruption of the hepatic tissue architecture characterized by anarchic deposition and excess of the extracellular matrix. The objective of this study was to evaluate hepatic fibrosis in HIV/HCV co-infected individuals as compared to HCV mono-infected. METHODS: A total of 97 participants (mean age 60.2 ± 14.3 years and 0.76 male/female sex ratio) was enrolled in a study conducted in Yaoundé, Cameroon from November 2018 to January 2019. Liver fibrosis was assessed by the APRI score (Aspartate Aminotransferase or AST/Platelet Ratio Index) which identifies the stage of fibrosis as classified by the Metavir system (F0 to F4). CD4 counts and plasmatic HIV viral load of HIV/HCV co-infected individuals were determined and the correlation between hepatic fibrosis and immuno-virological status established. Statistical analysis was done using Microsoft Excel 2016 and EpiInfo7 software. RESULTS: A high proportion (63.6%) of HIV/HCV co-infected participants had an abnormal AST level: 73.6 ± 45.8 IU/L as compared to 58.5 ± 39.3 IU/L (59.3%) among HCV mono-infected participants. The frequency of thrombocytopenia was 63.6% with a mean platelet count of 137 ± 50 ×  103 IU/L in HIV/HCV co-infected participants as compared to 176 ± 67 × 103 IU/L in HCV mono-infected participants (38.4%). The progression of hepatic fibrosis in participants with clinically significant fibrosis: F2, F3 and F4 was higher among HIV/HCV co-infected and the mean APRI score was 1.7 ± 1.4 versus 1 ± 0.8 among HCV mono-infected (26.7%). All participants (100%) with detectable HIV viral load had clinically significant fibrosis compared to 33.4% in those with undetectable HIV viral load (p = 0.55). Only 42.9% participants with CD4 >  500 cells/µL had clinically significant fibrosis (p = 0.72) while 100% participants with CD4 <  200 cells/µL had clinically significant fibrosis (p = 0.58). CONCLUSIONS: A high level of AST combined with thrombocytopenia (APRI score > 1.5) is an indicator of hepatic fibrosis in HIV/HCV co-infected individuals. Because of its non-invasive and less costly nature, the APRI score can be a suitable biomarker to monitor hepatic fibrosis in HIV/HCV co-infected individuals in resource constrained settings.

First case of Dolutegravir and Darunavir/r multi drug-resistant HIV-1 in Cameroon following exposure to Raltegravir: lessons and implications in the era of transition to Dolutegravir-based regimens.

BACKGROUND: Sub-Saharan African countries are transitioning to dolutegravir-based regimens, even for patients with extensive previous drug exposure, including first-generation integrase strand-transfer inhibitors (INSTI) such as raltegravir. Such exposure might have implications on cross-resistance to dolutegravir-based antiretroviral therapies (ART). CASE PRESENTATION: We report a 65 years old Cameroonian, previously exposed to raltegravir, and failing on third-line treatment with multi-drug resistance to darunavir/r and dolutegravir. Genotypic resistance testing (GRT) and viral tropism were performed during monitoring time points. The patient initiated ART in August 2007. At the time point of the first (29.04.2010), second (01.12.2017) and third (08.08.2019) GRT, prior ART exposure included 3TC, d4T, NVP and EFV; additionally TDF, DRV/r and RAL; and additionally ABC and DTG respectively. First GRT revealed mutations associated with resistance only to first-generation Non-nucleoside reverse transcriptase inhibitors (NNRTI). Second GRT revealed mutations associated with high-level resistance to all NRTIs, first generation NNRTIs, all ritonavir boosted protease inhibitors (PI/r), and all INSTI, while viral tropism (using geno2pheno) revealed a CCR5-tropic virus with a false positive rate (FPR) of 60.9% suggesting effectiveness of maraviroc (MRV). The third GRT showed high-level resistance to NRTI, NNRTI, all PI and all INSTI, with additional mutations (H221HY for NNRTI and S147G for INSTI), and a CCR5-tropic virus with a slightly reduced FPR (57.0%). Without any locally available active therapeutic option, the patient has been on a maintenance therapy with "DRV/r (600mg x 2/day)+TDF+3TC" and patient/family-centered adherence has been reinforced. Since the first viral load (VL) measurement in 2010, the patient has had 12 VL tests with the VL ranging from 4.97 Log to 6.44 Log copies/mL and the CD4 count never exceeded 200 cells/µL. CONCLUSIONS: As African countries transition to dolutegravir-based regimens, prior raltegravir-exposure may prompt selection (and potential transmission) of dolutegravir-resistance, supporting case surveillance.

Genetic variability of the U5 and downstream sequence of major HIV-1 subtypes and circulating recombinant forms.

The critical role of the regulatory elements at the 5' end of the HIV-1 genome in controlling the life cycle of HIV-1 indicates that this region significantly influences virus fitness and its biological properties. In this study, we performed a detailed characterization of strain-specific variability of sequences from the U5 to upstream of the gag gene start codon of diverse HIV-1 strains by using next-generation sequencing (NGS) techniques. Overall, we found that this region of the HIV-1 genome displayed a low degree of intra-strain variability. On the other hand, inter-strain variability was found to be as high as that reported for gag and env genes (13-17%). We observed strain-specific single point and clustered mutations in the U5, PBS, and gag leader sequences (GLS), generating potential strain-specific transcription factor binding sites (TFBS). Using an infrared gel shift assay, we demonstrated the presence of potential TFBS such as E-box in CRF22_01A, and Stat 6 in subtypes A and G, as well as in their related CRFs. The strain-specific variation found in the sequence corresponding at the RNA level to functional domains of the 5' UTR, could also potentially impact the secondary/tertiary structural rearrangement of this region. Thus, the variability observed in this 5' end of the genomic region of divergent HIV-1 strains strongly suggests that functions of this region might be affected in a strain-specific manner. Our findings provide new insights into DNA-protein interactions that regulate HIV-1 replication and the influence of strain characterization on the biology of HIV-1 infection.

Performance of the BD FACSPresto near to patient analyzer in comparison with representative conventional CD4 instruments in Cameroon.

BACKGROUND: In the context of scaling the viral load in resource limited settings, following HIV infected patient's adults and children with CD4+ T-lymphocyte count still very important in settings where the decentralization of treatment still has some challenges. Effective HIV monitoring in these resource-constrained settings needs affordable and reliable CD4+ T lymphocytes enumeration methods. We investigated the validity of a BD FACSPresto POC which is a dedicated system for enumeration that uses immunofluorescent technologies. In this study, we have assessed the sensitivity, specificity and correlation between most representative flow cytometry instruments present in Cameroon with more than 5000 CD4 T cells tests per year including FACSCalibur, FACSCount, and PIMA POC from Becton-Dickinson and ALERE respectively. METHODS: 268 patients aged from 1 to 72 years old were enrolled and included in the study after inform consent. The BD FACSPresto POC CD4+ T cell technology was placed at CIRCB and operated by technician staff. HIV infected patients were from Chantal BIYA international reference Center (CIRCB), Centre de Sante Catholique de NKOLODOM, Centre de Sante Catholique de BIKOP and CASS de Nkolndongo-Yaounde We compared the accuracy of the BD FACSPresto and three existing reference technologies with more than 5000 tests per year like FACSCalibur, FACSCount and PIMA according to the number of CD4 test done per year and their repartition in the country. Bland-Altman method and correlation analysis were used to estimate mean bias and 95% limits of agreement and to compare the methods, including analysis by subgroup of participant gestational age. In addition sensitivity and specificity were determined. Statistical significance was set at P-value < 0.05. RESULTS: The BD FACSPresto POC system has excellent precision, accuracy and linearity for CD4+ T lymphocytes enumeration. Good correlations were obtained between the BD FACSPresto poc system and other single platform methods. Bland-Altman plots showed interchangeability between two machines mean bias BD-FACSPresto vs PIMA = - 126,522(- 161,221 to - 91,822) BD-FACSPresto vs FACSCount = - 38,708 (- 58,935 to - 18,482) and FACSPresto vs FACSCALIBUR = 0.791(- 11,908 to 13,491). Mean difference with Absolute CD4+ T-lymphocyte values obtained from the BD FACSPresto system correlated well with PIMA, FACSCount, and FACSCalibur method with R2 equal to 0.88, 0.92 and 0.968 respectively with P < 0.001 for all. The mean comparison between values obtained from BD FACSPresto with PIMA, FACSCount, and FACSCalibur using paired T test give P = 0.17, P = 0.5 and P = 0.6 respectively meaning that there is no significant differences between values obtained with BD FACSPresto and PIMA, FACSCount or FACSCalibur CD4 enumeration machines. Further analysis revealed close agreement between all the three instruments with no significant difference between the forth methods (P = 0.91). CONCLUSION: This BD-FACSPresto POC system is a simple, robust and reliable system for enumeration of absolute and percentage of CD4+ T-lymphocytes especially suitable for remote areas with limited resources. Having one BD-FACSPresto POC system easy to use, should reduce the cost and thus increase and improved access to CD4 testing for HIV infected patients in resource-constrained countries. BD-FACSPresto POC CD4 will enable reduction in patient time and improve the overall quality of ART service count and may improve test access in remote areas. This technology can allow for greater decentralization and wider access to CD4 testing and ART.

Differential expression of Fas receptors (CD95) and Fas ligands (CD95L) in HIV infected and exposed uninfected children in Cameroon versus unexposed children.

INTRODUCTION: The number of HIV exposed uninfected (HEU) infants is increasing as vertical transmission is reducing. This subpopulation requires more investigations. This study aimed at comparing the expression level of soluble Fas receptors (FasR) and ligands (FasL) between HIV infected, HEU and unexposed children. METHODS: Eighty eight HIV-1infected, 86 HEU and 38 HIV unexposed children were recruited. Soluble FasR and FasL were measured in their plasma. Mann-Whitney U-Test was used to compare groups with 95% confidence. Spearman coefficient was used to test the correlation with CD4 and viral load (VL). RESULTS: Overall plasma levels of FasR were higher than that of FasL. The concentration of FasR and FasL were significantly higher in HIV-1 infected children in comparison to HEU and unexposed children. There was no difference in the plasma level of FasL in HIV infected compared to HEU children. A significant difference was observed between HIV infected children and HEU children (P=0.001) for the FasL. FasR were higher in both HIV infected and unexposed children compared to HEU children. There was a positive correlation (rs=+0.4; p=0.01) in ARV treated children between CD4 count and FasL concentration. Significant negative correlation (rs=-0.3; p=0.040) in ARV naïve children was observed between CD4 percentage and FasL. Significant and positive correlation (rs=+0.4; p=0.008) was observed between the VL and FasL in HIV infected, treated or not. CONCLUSION: HEU children differ from HIV infected and unexposed children as the level of FasL/R expression is concerned. HEU should be considered different from HIV unexposed although exempt from virus as some immune dysfunctions have been reported among them.