Extragenital Sexually Transmitted Infections Among High-Risk Men Who Have Sex With Men in Johannesburg, South Africa.

BACKGROUND: In South Africa, extragenital etiological sexually transmitted infection (STI) screening among men who have sex with men (MSM) is not routinely available. We aimed to determine the prevalence of STI pathogens at rectal and pharyngeal sites, syphilis seroprevalence, and associated risk factors among a selection of high-risk MSM without symptomatic urethritis attending a men's health clinic in Johannesburg, South Africa. METHODS: A cross-sectional study was conducted in 2022. Enrolled clients self-reported demographic, sexual behavioral risks, and clinical information. Client or clinician-collected rectal and pharyngeal swabs were tested for Neisseria gonorrhoeae, Chlamydia trachomatis, Mycoplasma genitalium, and Trichomonas vaginalis. C. trachomatis-positive rectal samples were reflex tested for lymphogranuloma venereum. Blood specimens were screened for syphilis. Univariate and multivariate regression models were used to determine factors independently associated with the presence of an extragenital STI or syphilis. RESULTS: Among the 97 participants (median age, 29 years), 24.7% had an extragenital STI and 9.4% had high nontreponemal antibody titers (rapid plasma reagin ≥1:16). Rectal STIs were detected in 26.4% participants: N. gonorrhoeae (14.3%), C. trachomatis (9.9%), and M. genitalium (5.5%). Pharyngeal STIs were less prevalent (4.1%). Overall, the prevalence of any STI was 41%. Sex under the influence of drugs (adjusted odds ratio, 4.94; 95% confidence interval, 1.56-15.69) and engaging in condomless receptive anal intercourse with a casual partner (adjusted odds ratio, 8.36; 95% confidence interval, 1.73-40.28) were independent risk factors for having an extragenital STI. CONCLUSIONS: The high burden of extragenital STIs and active syphilis in asymptomatic MSM underscores the importance of routine etiological screening in this key population, as the syndromic approach would not enable detection or treatment of these infections.

Higher CCR5 density on CD4 + T-cells in mothers and infants is associated with increased risk of in-utero HIV-1 transmission.

OBJECTIVE: CCR5-tropic viruses are preferentially transmitted during perinatal HIV-1 infection. CCR5 density on CD4 + T-cells likely impacts susceptibility to HIV-1 infection. DESIGN: Fifty-two mother-infant dyads were enrolled. All mothers were living with HIV-1, 27 of the infants acquired HIV-1 in utero and 25 infants remained uninfected. METHODS: CCR5 density, together with frequencies of CD4 + and CD8 + T-cells expressing immune activation (CCR5, ICOS and HLA-DR) and immune checkpoint (TIGIT and PD-1) markers, were measured in whole blood from the dyads close to delivery. RESULTS: Compared with mothers who did not transmit, mothers who transmitted HIV-1 had less exposure to ART during pregnancy ( P = 0.015) and higher plasma viral load close to delivery ( P = 0.0005). These mothers, additionally, had higher CCR5 density on CD4 + and CD8 + T-cells and higher frequencies of CCR5, ICOS and TIGIT-expressing CD8 + T-cells. Similarly, compared with infants without HIV-1, infants with HIV-1 had higher CCR5 density on CD4 + and CD8 + T-cells and higher frequencies of CCR5, TIGIT, and PD-1-expressing CD4 + and CD8 + T-cells as well as higher frequencies of HLA-DR-expressing CD8 + T-cells. CCR5 density on maternal CD4 + T-cells remained significantly associated with transmission after adjusting for maternal viral load and CD4 + T cell counts. Mother-infant dyads with shared high CCR5 density phenotypes had the highest risk of transmission/acquisition of infection compared with dyads with shared low-CCR5 density phenotypes. CONCLUSION: This study provides strong evidence of a protective role for a combined mother-infant low CD4 + T-cell CCR5 density phenotype in in-utero transmission/acquisition of HIV-1.

The evaluation of the Allplex™ BV molecular assay for the diagnosis of bacterial vaginosis in symptomatic South African females.

Bacterial vaginosis (BV) is a dysbiosis of vaginal microbiota characterized by a shift from Lactobacillus species predomination to a heterogeneous mixture of anaerobes. We compared the performance characteristics of the Allplex ™ BV molecular assay with the reference test, Nugent score microscopy, for vaginal swab specimens from symptomatic South African women. A total of 213 patients were enrolled, of whom 99 (46.5%) and 132 (62.0%) were diagnosed with BV by Nugent and Allplex™, respectively. The Allplex™ BV assay displayed a sensitivity of 94.9% (95% CI, 88.7%-97.8%) and a specificity of 66.7% (95% CI, 57.6%-74.6%), with an agreement of 79.8% (95% CI, 73.9%-84.7%) (κ = 0.60). Assay design may be enhanced for improved specificity by accounting for differences in healthy and BV-associated vaginal microbiomes among women of different ethnicities.

Etiological Surveillance of Vaginal Discharge Syndrome in South Africa: 2019 to 2020.

BACKGROUND: The syndromic management of vaginal discharge syndrome (VDS) is challenging because of the prevalence of mixed infection with sexually transmitted infection (STI) pathogens and non-STI causes, such as bacterial vaginosis and candidiasis (CA). We aimed to determine the relative prevalence of VDS etiologies in women presenting to sentinel primary health care clinics in South Africa. Secondary objectives were to ascertain the predictive value of speculum findings for the presence of STI pathogens and the proportion of women presenting with clinical features of CA who had identifiable yeast on vaginal smear microscopy. METHODS: Consecutive, consenting women with complaints of abnormal vaginal discharge were enrolled between January 1, 2019, and December 31, 2020. Genital discharge swab and blood specimens were collected and transported to a central STI reference laboratory in Johannesburg. RESULTS: A total of 364 women were enrolled at 3 sentinel sites. Bacterial vaginosis was the most common cause of VDS (163 of 361 [45.2%]; 95% confidence interval [CI], 40.1%-50.3%); however, a significant proportion had STI coinfection (71 of 163 [43.6%]; 95% CI, 35.8%-51.5%). The predominant STI etiology was Chlamydia trachomatis (73 [20.2%]; 95% CI, 16.4%-24.7%). An abnormal speculum finding had poor predictive value for STIs, and Gram stain microscopy showed yeast in only 37.2% of vaginal smears from women with CA symptoms. CONCLUSIONS: Bacterial vaginosis is the predominant cause of VDS in South Africa; however, STI coinfection is common. Clinical findings are poorly predictive of STI etiologies or candidiasis; therefore, a rapid and accurate STI point-of-care test would be useful in optimizing VDS management.

Normalization of B Cell Subsets but Not T Follicular Helper Phenotypes in Infants With Very Early Antiretroviral Treatment.

Introduction: Infant HIV-1-infection is associated with high morbidity and mortality if antiretroviral treatment (ART) is not initiated promptly. We characterized development of circulating T follicular helper cells (cTfh) and their relationship to naïve/memory B cell subsets in a cohort of neonates initiating ART within the first week of life. Methods: Infants were diagnosed within 48 hours of birth and started ART as soon as possible. The frequency and phenotype of cTfh and B cells were analyzed at enrollment (birth -19 days) and at 4, 12, and 72 weeks of age in blood of 27 HIV-1-intrauterine-infected and 25 HIV-1 exposed uninfected (HEU) infants as part of a study in Johannesburg, South Africa. cTfh cells were divided into Tfh1, Tfh2, and Tfh17 subsets. B cell phenotypes were defined as naïve, resting memory, activated memory and tissue-like memory cells. Results: HIV-1-infected infants had higher frequencies of cTfh cells than HEU infants up to 12 weeks of age and these cTfh cells were polarized toward the Tfh1 subset. Higher frequencies of Tfh1 and lower frequencies of Tfh2 and Tfh17 correlated with lower CD4+ T cell percentages. Lower frequencies of resting memory, with corresponding higher frequencies of activated memory B cells, were observed with HIV-1 infection. Importantly, dysregulations in B cell, but not cTfh cell, subsets were normalized by 72 weeks. Conclusion: Very early ART initiation in HIV-1-infected infants normalizes B cell subsets but does not fully normalize perturbations in cTfh cell subsets which remain Tfh1 polarized at 72 weeks. It remains to be determined if very early ART improves vaccine antibody responses despite the cTfh and B cell perturbations observed over the time course of this study.

The impact of bone marrow stromal antigen-2 (BST2) gene variants on HIV-1 control in black South African individuals.

Bone marrow stromal cell antigen 2 (BST2 or tetherin) is a host-encoded, interferon-inducible antiviral restriction factor which blocks the release of enveloped viruses. Few studies have assessed the role of BST2 polymorphisms on HIV-1 acquisition or disease progression in sub-Saharan Africa. This study investigated the frequency of four HIV-1-associated BST2 variants rs3217318, rs12609479, rs10415893 and rs113189798 in uninfected and HIV-1 infected black South Africans. Homozygosity for the rs12609479-A minor allele, previously associated with decreased HIV-1 acquisition risk, was underrepresented in HIV-1 uninfected black South Africans (2%) compared to reference African (9%) and in particular European populations (61%) (p = .047 and p < .0001, respectively). To determine if any of these gene variants influenced HIV-1 control in the absence of antiretroviral treatment (ART), we compared HIV-1 infected ART-naïve progressors [n = 72] and controllers [n = 71], the latter includes elite controllers [EC: n = 23; VL < 50 RNA copies/ml]. Heterozygosity for the rs12609479 SNP (G/A) was enriched in progressors compared to ECs (47.2% vs 21.7%, OR = 3.50 [1.16-10.59], p = .03), while rs113189798 heterozygosity (A/G) showed a strong trend of overrepresentation in ECs compared to progressors (47.8% vs 26.4%, OR = 0.39 [0.14-1.04], p = .07). Heterozygosity for the promoter indel rs3217318 (i19/Δ19) was associated with a faster rate of CD4+ T-cell decline in progressors (p = .0134). Carriage of the rs3217318 (i19/Δ19), rs12609479 (G/G), rs10415893(G/A) and rs113189798 (A/G) combined genotype, denoted as i19Δ19 GG GA AG, was associated with significantly higher CD4+ T-cell counts in progressors (p = .03), a finding predominantly driven by the _GG_AG combination. Our data suggest that the possession of select BST2 genotype combinations may be implicated in HIV-1 disease progression and natural spontaneous control.

LRP/LR Antibody Mediated Rescuing of Amyloid-ß-Induced Cytotoxicity is Dependent on PrPc in Alzheimer's Disease.

The neuronal perturbations in Alzheimer's disease are attributed to the formation of extracellular amyloid-ß (Aß) neuritic plaques, composed predominantly of the neurotoxic Aß42 isoform. Although the plaques have demonstrated a role in synaptic dysfunction, neuronal cytotoxicity has been attributed to soluble Aß42 oligomers. The 37kDa/67kDa laminin receptor has been implicated in Aß42 shedding and Aß42-induced neuronal cytotoxicity, as well as internalization of this neurotoxic peptide. As the cellular prion protein binds to both LRP/LR and Aß42, the mechanism underlying this cytotoxicity may be indirectly due to the PrPc-Aß42 interaction with LRP/LR. The effects of this interaction were investigated by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assays. PrPc overexpression significantly enhanced Aß42 cytotoxicity in vitro, while PrP-/-  cells were more resistant to the cytotoxic effects of Aß42 and exhibited significantly less cell death than PrPc expressing N2a cells. Although anti-LRP/LR specific antibody IgG1-iS18 significantly enhanced cell viability in both pSFV1-huPrP1-253 transfected and non-transfected cells treated with exogenous Aß42, it failed to have any cell rescuing effect in PrP-/-  HpL3-4 cells. These results suggest that LRP/LR plays a significant role in Aß42-PrPc mediated cytotoxicity and that anti-LRP/LR specific antibodies may serve as potential therapeutic tools for Alzheimer's disease.