SARS-CoV-2 Breakthrough Infections after Third Doses Boost IgG Specific Salivary and Blood Antibodies.

SARS-CoV-2 breakthrough infections, associated with waning immunity, increase systemic antibody levels. In this study, we analyzed the impact of the infection timing on the magnitude of the systemic humoral response and whether breakthrough infections also boost antibody levels in the salivary compartment. We observed that the combination of infection plus vaccination, regardless of infection timing, produced a sharp increase in systemic antibodies, which were higher in subjects infected after third doses. Moreover, despite high systemic antibody levels, breakthrough infections after dose three occurred and boosted antibody levels in the salivary compartment. These results suggest that current vaccination strategies against COVID-19 should be improved. Results also showed that determination of salivary antibodies against SARS-CoV-2 could be a valuable tool in disease prevalence studies, for the follow-up of vaccinated individuals, and to assist vaccination strategies against COVID-19, especially in settings where blood sampling cannot be fulfilled.

COVID-19 Vaccination Responses with Different Vaccine Platforms in Patients with Inborn Errors of Immunity.

Patients with inborn errors of immunity (IEI) in Argentina were encouraged to receive licensed Sputnik, AstraZeneca, Sinopharm, Moderna, and Pfizer vaccines, even though most of the data of humoral and cellular responses combination on available vaccines comes from trials conducted in healthy individuals. We aimed to evaluate the safety and immunogenicity of the different vaccines in IEI patients in Argentina. The study cohort included adults and pediatric IEI patients (n = 118) and age-matched healthy controls (HC) (n = 37). B cell response was evaluated by measuring IgG anti-spike/receptor binding domain (S/RBD) and anti-nucleocapsid(N) antibodies by ELISA. Neutralization antibodies were also assessed with an alpha-S protein-expressing pseudo-virus assay. The T cell response was analyzed by IFN-γ secretion on S- or N-stimulated PBMC by ELISPOT and the frequency of S-specific circulating T follicular-helper cells (TFH) was evaluated by flow cytometry.No moderate/severe vaccine-associated adverse events were observed. Anti-S/RBD titers showed significant differences in both pediatric and adult IEI patients versus the age-matched HC cohort (p < 0.05). Neutralizing antibodies were also significantly lower in the patient cohort than in age-matched HC (p < 0.01). Positive S-specific IFN-γ response was observed in 84.5% of IEI patients and 82.1% presented S-specific TFH cells. Moderna vaccines, which were mainly administered in the pediatric population, elicited a stronger humoral response in IEI patients, both in antibody titer and neutralization capacity, but the cellular immune response was similar between vaccine platforms. No difference in humoral response was observed between vaccinated patients with and without previous SARS-CoV-2 infection.In conclusion, COVID-19 vaccines showed safety in IEI patients and, although immunogenicity was lower than HC, they showed specific anti-S/RBD IgG, neutralizing antibody titers, and T cell-dependent cellular immunity with IFN-γ secreting cells. These findings may guide the recommendation for a vaccination with all the available vaccines in IEI patients to prevent COVID-19 disease.

Heterologous gam-COVID-vac (sputnik V)/mRNA-1273 (moderna) vaccination induces a stronger humoral response than homologous sputnik V in a real-world data analysis.

OBJECTIVES: To compare the homologous prime-boost vaccination scheme of Gam-COVID-Vac (Sputnik V (SpV)) to its heterologous combination with mRNA-1273 (Moderna (Mod)) vaccine. METHODS: SARS-CoV-2 anti-spike (S)-receptor binding domain (RBD) IgG concentration was assessed three to seven weeks after complete vaccination. Reactogenicity was evaluated by declared side events and medical assistance required until day 7 post boost. RESULTS: Of 190 participants enrolled, 105 received homologous SpV/SpV and the remaining heterologous SpV/Mod vaccination scheme, respectively. Median (interquartile range (IQR)) age was 54 (37-63) years, 132 out of 190 (69.5%) were female, and 46 out of 190 (24.2%) individuals had a prior confirmed COVID-19. Anti-S-RBD IgG median (IQR) titers were significantly higher for SpV/Mod (2511 (1476-3992) binding antibody units (BAU)/mL) than for SpV/SpV (582 (209-1609) BAU/mL; p < 0.001] vaccination scheme. In a linear model adjusted for age, gender, time to the serological assay, and time between doses, SpV/Mod (4.154 (6.585-615.554); p < 0.001] and prior COVID (3.732 (8.641-202.010); p < 0.001) were independently associated with higher anti-S-RBD IgG values. A higher frequency of mild and moderate adverse effects was associated with the heterologous scheme (20 of 85 (23.5%) vs. 13 of 105 (12.4%); p = 0.043 and 27 of 85 (31.8%) vs. 14 of 105 (13.3%); p = 0.002), respectively, although it was well tolerated by all individuals and no medical assistance was required. DISCUSSION: The heterologous SpV/Mod combination against SARS-CoV-2 is well tolerated and significantly increases humoral immune response as compared to the homologous SpV/SpV immunization.

Humoral response to the BBIBP-CorV vaccine over time in healthcare workers with or without exposure to SARS-CoV-2.

SARS-CoV-2-specific humoral response was analyzed over time in a group of healthcare workers with or without exposure to SARS-CoV-2, who underwent vaccination with BBIBP-CorV (Sinopharm) vaccine in Argentina. Seroconversion rates in unexposed subjects after the first and second doses were 40 % and 100 %, respectively, showing a significant increase in antibody concentrations from dose 1 to dose 2 (p < 0.0001). The highest antibody concentrations were found in younger subjects and women, remaining significantly associated in a multivariable linear regression model (p = 0.005). A single dose of the BBIBP-CorV vaccine induced a strong antibody response in individuals with prior SARS-CoV-2infection, while a second dose did not increase this response. A sharp increase in antibody concentrations was observed following SARS-CoV-2 infection in those participants who became infected after the first and second doses (p = 0.008). Individuals with SARS-CoV-2 exposure prior to vaccination showed significantly higher anti-spike IgG antibody levels, at all-time points, than those not exposed (p < 0.001). Higher antibody titers were induced by a single dose in previously SARS-CoV-2 infected individuals than those induced in naïve subjects by two doses of the vaccine (p < 0.0001). Three months after the second dose both groups showed a decline in antibody levels, being more abrupt in unexposed subjects. Overall, our results showed a trend towards lower antibody concentrations over time following BBIBP-CorV vaccination. Sex and age seem to influence the magnitude of the humoral response in unexposed subjects while the combination of exposure to SARS-CoV-2 plus vaccination, whatever the sequence of the events was, produced a sharp increase in antibody levels. Evaluation of the humoral responses over time and the analysis of the induction and persistence of memory B and T cell responses, are needed to assess long-term immune protection induced by BBIBP-CorV vaccine.

Twenty-year follow-up of an outbreak of hepatitis C in a small rural town of Argentina: The O'Brien Project.

INTRODUCTION AND OBJECTIVES: In 1999, a population-based survey showed a 5.6 % (102/1832) prevalence of HCV infection in O'Brien, a small rural town of Argentina. The aim of this study was to assess the impact of screening, clinical evaluation and antiviral therapy on elimination of HCV after 20 years of follow-up. PATIENTS AND METHODS: HCV+ subjects (n=102) underwent clinical, biochemical and histological evaluation to assess the presence and severity of liver disease. Antiviral therapy included pegylated interferon + ribavirin in 2005 and direct antiviral agents from 2017. RESULTS: All viremic subjects (n=84) had genotype 1b with 90%-97.5% sequence homology scores, suggesting the existence of a common source of infection (use of unsafe injections administered by the same health professional). Liver biopsy (n=55) showed chronic hepatitis in all patients. The prevalence of cirrhosis was 28% overall (29/102) and 34.5% among viremic patients. Sustained virological response (SVR) was obtained in 20/34 (59%) patients treated with interferon. From 2005 to 2017, when oral antivirals became available 37/50 untreated patients died. Median age of this group in 2005 was 67 years. Six interferon non-responders and five naive subjects received direct antiviral agents and all developed SVR. Only 1/31 patient (3.2%) with SVR died and none developed decompensated cirrhosis or HCC. In 2019, a new population-based study showed that the prevalence of HCV in O'Brien decreased 20-fold, from 5.6% to 0.28% (3/1070). CONCLUSIONS: Despite the high mortality rate precluding timely access to direct antiviral agents, the O'Brien Project is a good example of HCV micro-elimination studies.

Evolutionary analysis of SARS-CoV-2 spike protein for its different clades.

The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become the main target for antiviral and vaccine development. Despite its relevance, e information is scarse about its evolutionary traces. The aim of this study was to investigate the diversification patterns of the spike for each clade of SARS-CoV-2 through different approaches. Two thousand and one hundred sequences representing the seven clades of the SARS-CoV-2 were included. Patterns of genetic diversifications and nucleotide evolutionary rate were estimated for the spike genomic region. The haplotype networks showed a star shape, where multiple haplotypes with few nucleotide differences diverge from a common ancestor. Four hundred seventy-nine different haplotypes were defined in the seven analyzed clades. The main haplotype, named Hap-1, was the most frequent for clades G (54%), GH (54%), and GR (56%) and a different haplotype (named Hap-252) was the most important for clades L (63.3%), O (39.7%), S (51.7%), and V (70%). The evolutionary rate for the spike protein was estimated as 1.08 × 10-3 nucleotide substitutions/site/year. Moreover, the nucleotide evolutionary rate after nine months of the pandemic was similar for each clade. In conclusion, the present evolutionary analysis is relevant as the spike protein of SARS-CoV-2 is the target for most therapeutic candidates; besides, changes in this protein could have consequences on viral transmission, response to antivirals and efficacy of vaccines. Moreover, the evolutionary characterization of clades improves knowledge of SARS-CoV-2 and deserves to be assessed in more detail as re-infection by different phylogenetic clades has been reported.

Influence of Hepatitis C virus coinfection on immune reconstitution in HIV subjects.

Despite successful HIV suppression by antiretroviral treatment (ART), immune activation may persist in HIV patients, contributing to an impaired immunological reconstitution and disease progression. Information regarding Hepatitis C virus (HCV) coinfection as a factor that accounts for immune activation in HIV subjects remains unclear. Furthermore, most studies have been carried out considering HIV/HCV patients as a whole, without taking into account the presence or absence of liver damage. Therefore, it is unknown if HCV and/or its liver-related disease could act as two independent factors contributing to the immune activation. In this study, we investigated the presence of immune activation in a cohort of 50 HIV/HCV patients by measuring cytokine levels, CD4+ T-cell counts and CD4/CD8 ratios. Six patient groups were defined according to HIV viral load, HCV status, and liver disease to assess the impact of each of these factors on immune activation and reconstitution in HIV/HCV patients. Only subjects with controlled HIV infection and cleared HCV displayed immunological parameters within normal ranges. The mere presence of HCV contributes to immune activation leading to an inappropriate immunological reconstitution. This state exacerbates in the presence of HCV-associated liver disease. Our results suggest that ART is not enough to suppress immune activation in the context of HIV/HCV coinfection, since both HCV and its liver-related disease would contribute to the immune activation. Given that immune activation worsens immunological reconstitution and clinical status, these results support the priority of HCV treatment in HIV/HCV patients and suggest the monitoring of their liver status.

A different gut microbiome linked to inflammation found in cirrhotic patients with and without hepatocellular carcinoma.

INTRODUCTION AND AIM: A pro-oncogenic intestinal microbiome was observed in murine models; however, no specific microbiome in patients with hepatocellular carcinoma (HCC) has been reported. We aimed to compare the gut microbiome found in cirrhotic patients with or without HCC. MATERIALS AND METHODS: From 407 patients with Child Pugh A/B cirrhosis prospectively followed, 25 with HCC (cases) were matched with 25 without HCC (wo-HCC) in a 1:1 ratio according to age, gender, etiology, Child Pugh and severity of portal hypertension. In addition, results were also compared with 25 healthy subjects. Fecal stool samples were sequenced for the V3-V4 region of the microbial 16S rRNA (Illumina MiSeq Platform). Plasma cytokines were quantified including interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α). RESULTS: We found a differential abundance in family members of Firmicutes with a 3-fold increase of Erysipelotrichaceae and a 5-fold decrease in family Leuconostocaceae in HCC when compared to wo-HCC controls. Genus Fusobacterium was found to be 5-fold decreased in HCC vs wo-HCC. The ratio bacteriodes/prevotella was increased in HCC. Three operational taxonomic units (OTUs), genus Odoribacter and Butyricimonas were more abundant in HCC, whereas a decreased abundance in Lachnospiraceae family genus Dorea was observed in HCC patients. A Random Forest model trained with differential abundant taxa correctly classified HCC individuals. This pattern was associated with an inflammatory milieu with a putative increased activation of NOD-like receptor pathways. CONCLUSION: We found a pattern of microbiome linked to inflammation that could be potentially useful as HCC biomarker after follow-up validation studies.

Evolutionary dynamics of Hepatitis C virus in a chronic HIV co-infected patient and its correlation with the immune status.

The HCV evolutionary dynamics play a key role in the infection onset, maintenance of chronicity, pathogenicity, and drug resistance variants fixation, and are thought to be one of the main caveats in the development of an effective vaccine. Previous studies in HCV/HIV co-infected patients suggest that a decline in the immune status is related with increases in the HCV intra-host genetic diversity. However, these findings are based on single point sequence diversity measures or coalescence analyses in several virus-host interactions. In this work, we describe the molecular evolution of HCV-E2 region in a single HIV-co-infected patient with two clearly defined immune conditions. The phylogenetic analysis of the HCV-1a sequences from the studied patient showed that he was co-infected with three different viral lineages. These lineages were not evenly detected throughout time. The sequence diversity and coalescence analyses of these lineages suggested the action of different evolutionary patterns in different immune conditions: a slow rate, drift-like process in an immunocompromised condition (low levels of CD4+ T lymphocytes); and a fast rate, variant-switch process in an immunocompetent condition (high levels of CD4+ T lymphocytes).

Preferential association of hepatitis C virus with CD19+ B cells is mediated by complement system.

Extrahepatic disease manifestations are common in chronic hepatitis C virus (HCV) infection. The mechanism of HCV-related lymphoproliferative disorders is not fully understood. Recent studies have found that HCV in peripheral blood mononuclear cells from chronically infected patients is mainly associated with cluster of differentiation 19-positive (CD19+ ) B cells. To further elucidate this preferential association of HCV with B cells, we used in vitro cultured virus and uninfected peripheral blood mononuclear cells from healthy blood donors to investigate the necessary serum components that activate the binding of HCV to B cells. First, we found that the active serum components were present not only in HCV carriers but also in HCV recovered patients and HCV-negative, healthy blood donors and that the serum components were heat-labile. Second, the preferential binding activity of HCV to B cells could be blocked by anti-complement C3 antibodies. In experiments with complement-depleted serum and purified complement proteins, we demonstrated that complement proteins C1, C2, and C3 were required to activate such binding activity. Complement protein C4 was partially involved in this process. Third, using antibodies against cell surface markers, we showed that the binding complex mainly involved CD21 (complement receptor 2), CD19, CD20, and CD81; CD35 (complement receptor 1) was involved but had lower binding activity. Fourth, both anti-CD21 and anti-CD35 antibodies could block the binding of patient-derived HCV to B cells. Fifth, complement also mediated HCV binding to Raji cells, a cultured B-cell line derived from Burkitt's lymphoma. CONCLUSION: In chronic HCV infection, the preferential association of HCV with B cells is mediated by the complement system, mainly through complement receptor 2 (CD21), in conjunction with the CD19 and CD81 complex. (Hepatology 2016;64:1900-1910).

American tegumentary leishmaniasis: T-cell differentiation profile of cutaneous and mucosal forms-co-infection with Trypanosoma cruzi.

American tegumentary leishmaniasis displays two main clinical forms: cutaneous (CL) and mucosal (ML). ML is more resistant to treatment and displays a more severe and longer evolution. Since both forms are caused by the same Leishmania species, the immunological response of the host may be an important factor determining the evolution of the disease. Herein, we analyzed the differentiation and memory profile of peripheral CD4(+) and CD8(+) T lymphocytes of patients with CL and ML and their Leishmania-T. cruzi co-infected counterparts. We measured the expression of CD27, CD28, CD45RO, CD127, PD-1 and CD57, together with interferon-γ and perforin. A highly differentiated phenotype was reflected on both T subsets in ML and preferentially on CD8(+) T cells in CL. A positive trend toward a higher T differentiation profile was found in T. cruzi-infected CL and ML patients as compared with Leishmania single infections. Association between CD8(+) T-cell differentiation and illness duration was found within the first year of infection, with progressive increase of highly differentiated markers over time. Follow-up of patients with good response to therapy showed predominance of early differentiated CD8(+) T cells and decrease of highly differentiated cells, while patients with frequent relapses presented the opposite pattern. CD8(+) T cells showed the most striking changes in their phenotype during leishmaniasis. Patients with long-term infections showed the highest differentiated degree implying a relation between T differentiation and parasite persistence. Distinct patterns of CD8(+) T differentiation during follow-up of different clinical outcomes suggest the usefulness of this analysis in the characterization of Leishmania-infected patients.

New evidence of replication of hepatitis C virus in short-term peripheral blood mononuclear cell cultures.

BACKGROUND: Even though hepatocytes are the main site for hepatitis C virus (HCV) replication, peripheral blood mononuclear cells (PBMC) have also been proposed as a suitable site for HCV replication. However, this issue still remains under discussion. We have previously developed an innovative system where HCV-RNA can be recovered during PBMC culture from HCV infected patients. Thus, the aim of this work was to use this novel approach in order to observe the evolution and replication of HCV genotype 1b in the PBMC of an HIV-HCV coinfected patient. METHODS: HCV-RNA was extracted from serum, uncultured PBMC and PBMC culture at day 6, 20 and 33. The evolutionary analysis was performed using the direct sequences of three viral regions: 5'UTR, E2 and NS5A. Additionally, E2 region was cloned in order to extend the evolutive analysis. RESULTS: In the present work, the molecular characterization of HCV along the culture showed a clear dynamic evolving process with the appearance of several nucleotide or amino acid changes in the three regions analyzed. Furthermore, the population analysis of E2 clones showed emerging and loss of lineages which indicate the fast evolutive dynamics of this system. CONCLUSIONS: Since evolution can take place only if the virus is replicating in the culture, this finding constitutes an important evidence of viral replication in PBMC. Moreover, this extrahepatic compartment could be very important due to the presence of distinctive variants that could be responsible for resistance to treatment, viral pathogenesis and other clinical implications.

Hepatitis C virus diversification in Argentina: comparative analysis between the large city of Buenos Aires and the small rural town of O'Brien.

BACKGROUND: The estimated prevalence of HCV infection in Argentina is around 2%. However, higher rates of infection have been described in population studies of small urban and rural communities. The aim of this work was to compare the origin and diversification of HCV-1b in samples from two different epidemiological scenarios: Buenos Aires, a large cosmopolitan city, and O'Brien, a small rural town with a high prevalence of HCV infection. PATIENTS AND METHODS: The E1/E2 and NS5B regions of the viral genome from 83 patients infected with HCV-1b were sequenced. Phylogenetic analysis and Bayesian Coalescent methods were used to study the origin and diversification of HCV-1b in both patient populations. RESULTS: Samples from Buenos Aires showed a polyphyletic behavior with a tMRCA around 1887-1900 and a time of spread of infection approximately 60 years ago. In contrast, samples from ÓBrien showed a monophyletic behavior with a tMRCA around 1950-1960 and a time of spread of infection more recent than in Buenos Aires, around 20-30 years ago. CONCLUSION: Phylogenetic and coalescence analysis revealed a different behavior in the epidemiological histories of Buenos Aires and ÓBrien. HCV infection in Buenos Aires shows a polyphyletic behavior and an exponential growth in two phases, whereas that in O'Brien shows a monophyletic cluster and an exponential growth in one single step with a more recent tMRCA. The polyphyletic origin and the probability of encountering susceptible individuals in a large cosmopolitan city like Buenos Aires are in agreement with a longer period of expansion. In contrast, in less populated areas such as O'Brien, the chances of HCV transmission are strongly restricted. Furthermore, the monophyletic character and the most recent time of emergence suggest that different HCV-1b ancestors (variants) that were in expansion in Buenos Aires had the opportunity to colonize and expand in O'Brien.

Investigation of residual hepatitis C virus in presumed recovered subjects.

UNLABELLED: Recent studies have found hepatitis C virus (HCV) RNA in peripheral blood mononuclear cells (PBMCs) of the majority of presumed recovered subjects. We investigated this unexpected finding using samples from patients whose HCV RNA and anti-HCV status had been serially confirmed. HCV RNA was detected in PBMCs from 66 of 67 chronic HCV carriers. Subpopulation analysis revealed that the viral load (log copies/10(6) cells) in B cells (4.14 ± 0.71) was higher than in total PBMCs (3.62 ± 0.71; P < 0.05), T cells (1.67 ± 0.88; P < 0.05), and non-B/T cells (2.48 ± 1.15; P < 0.05). HCV negative-strand RNA was not detected in PBMCs from any of 25 chronically infected patients. No residual viral RNA was detected in total PBMCs or plasma of 59 presumed recovered subjects (11 spontaneous and 48 treatment induced) using nested real-time polymerase chain reaction with a detection limit of 2 copies/µg RNA (from ≈ 1 × 10(6) cells). PBMCs from 2 healthy HCV-negative blood donors became HCV RNA positive, with B-cell predominance, when mixed in vitro with HCV RNA-positive plasma, thus passively mimicking cells from chronic HCV carriers. No residual HCV was detected in liver or other tissues from 2 spontaneously recovered chimpanzees. CONCLUSION: (1) HCV RNA was detected in PBMCs of most chronic HCV carriers and was predominant in the B-cell subpopulation; (2) HCV detected in PBMCs was in a nonreplicative form; (3) HCV passively adsorbed to PBMCs of healthy controls in vitro, becoming indistinguishable from PBMCs of chronic HCV carriers; and (4) residual HCV was not detected in plasma or PBMCs of any spontaneous or treatment-recovered subjects or in chimpanzee liver, suggesting that the classic pattern of recovery from HCV infection is generally equivalent to viral eradication.

Non-Hodgkin lymphomas of the oral cavity in AIDS patients in a reference hospital of infectious diseases in Argentina: report of eleven cases and review of the literature.

INTRODUCTION: Extranodal non-Hodgkin lymphoma (NHL) were commonly described in AIDS patients and are related with an atypical morphology and aggressive clinical course. MATERIALS AND METHODS: In this single institutional study we evaluated the epidemiological, clinical, immunological, virological, histopathological and the outcome of eleven HIV/AIDS patients with oral cavity lymphomas (OCL). RESULTS: Nine were males and seven intravenous drug abusers. The median of age was 33 years and the median of CD4 T cell counts at the time of diagnosis was 97 cell/µL. The majority of tumors presented as large and ulcerated masses involving the gingiva, the palate and the jaw. Six of these tumors were diffuse large B-cell lymphomas (DLBCL); three were Burkitt's lymphomas and the final case was a plasmablastic lymphoma. An association with Epstein-Barr virus (EBV) was found in three of the ten tested cases by in situ hybridization (EBER 1 and 2 probes) and immunohistochemistry (LMP-1). Human herpes virus-8 (HHV-8) was detected by polymerase chain reaction (PCR) in only one neoplasm. Six patients died without specific treatment; four received chemotherapy and highly active antiretroviral therapy (HAART) and three of them presented a prolonged survival. DISCUSSION: Combination of HAART and chemotherapy should modify the poor prognosis of AIDS patients with OCL.