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Introduction: Novel point‐of‐care assays which measure urine tenofovir (TFV) concentrations may have a role in improving adherence monitoring for people living with HIV (PLHIV) receiving antiretroviral therapy (ART). However, further studies of their diagnostic accuracy, and whether results are associated with viraemia and drug resistance, are needed to guide their use, particularly in the context of the global dolutegravir rollout. Methods: We conducted a cross‐sectional evaluation among PLHIV receiving first‐line ART containing tenofovir disoproxil fumarate at enrolment into a randomized trial in two South African public sector clinics. We calculated the diagnostic accuracy of the Abbott point‐of‐care immunoassay to detect urine TFV compared to liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). We evaluated the association between point‐of‐care urine TFV results and self‐reported adherence, viraemia ≥1000 copies/ml and HIV drug resistance, among people receiving either efavirenz or dolutegravir‐based ART. Results: Between August 2020 and March 2022, we enrolled 124 participants. The median age was 39 (IQR 34–45) years, 55% were women, 74 (59.7%) were receiving efavirenz and 50 (40.3%) dolutegravir. The sensitivity and specificity of the immunoassay to detect urine TFV ≥1500 ng/ml compared to LC‐MS/MS were 96.1% (95% CI 90.0−98.8) and 95.2% (75.3−100.0), respectively. Urine TFV results were associated with short (p<0.001) and medium‐term (p = 0.036) self‐reported adherence. Overall, 44/124 (35.5%) had viraemia, which was associated with undetectable TFV in those receiving efavirenz (OR 6.01, 1.27−39.0, p = 0.014) and dolutegravir (OR 25.7, 4.20−294.8, p<0.001). However, in those with viraemia while receiving efavirenz, 8/27 (29.6%) had undetectable urine TFV, compared to 11/17 (64.7%) of those receiving dolutegravir. Drug resistance was detected in 23/27 (85.2%) of those receiving efavirenz and only 1/16 (6.3%) of those receiving dolutegravir. There was no association between urine TFV results and drug resistance. Conclusions: Among PLHIV receiving ART, a rapid urine TFV immunoassay can be used to accurately monitor urine TFV levels compared to the gold standard of LC‐MS/MS. Undetectable point‐of‐care urine TFV results were associated with viraemia, particularly among people receiving dolutegravir. Trial registration: Pan‐African Clinical Trials Registry: PACTR202001785886049. [ABSTRACT FROM AUTHOR]

HIV cerebrospinal fluid (CSF) escape, where HIV is suppressed in blood but detectable in CSF, occurs when HIV persists in the CNS despite antiretroviral therapy (ART). To determine the virus producing cell type and whether lowered CSF ART levels are responsible for CSF escape, we collected blood and CSF from 156 neurosymptomatic participants from Durban, South Africa. We observed that 28% of participants with an undetectable HIV blood viral load showed CSF escape. We detected host cell surface markers on the HIV envelope to determine the cellular source of HIV in participants on the first line regimen of efavirenz, emtricitabine, and tenofovir. We confirmed CD26 as a marker which could differentiate between T cells and macrophages and microglia, and quantified CD26 levels on the virion surface, comparing the result to virus from in vitro infected T cells or macrophages. The measured CD26 level was consistent with the presence of T cell produced virus. We found no significant differences in ART concentrations between CSF escape and fully suppressed individuals in CSF or blood, and did not observe a clear association with drug resistance mutations in CSF virus which would allow HIV to replicate. Hence, CSF HIV in the face of ART may at least partly originate in CD4+ T cell populations. Author summary: The brain may be a site where HIV persists despite antiretroviral therapy (ART). Persistence can manifest as cerebrospinal fluid (CSF) escape, where HIV is detectable in the CSF but not the blood in some individuals. The reasons for CSF escape are incompletely understood. Evidence from individuals mostly on second line protease inhibitor-based ART indicates that detectable HIV in this compartment may have acquired drug resistance. In this work we investigated HIV in blood and CSF of 156 participants from Durban, South Africa. We observed a very high prevalence of CSF escape of 28%. We aimed to find the cell type responsible for producing HIV in CSF escape and whether replication occurred because of lower CSF drug levels or because the virus has developed resistance to therapy. We found that at least some of the CSF HIV was produced by T cells, and that drug resistance was not always present. This suggests that at least part of the CSF HIV reservoir may be generated by either an infection mode not requiring drug resistance for viral replication, or by latently infected CD4+ T cells trafficking to and releasing HIV in the CSF without extensive viral replication taking place. [ABSTRACT FROM AUTHOR]

Female children and adults typically generate more efficacious immune responses to vaccines and infections than age-matched males, but also suffer greater immunopathology and autoimmune disease. We here describe, in a cohort of > 170 in utero HIV-infected infants from KwaZulu-Natal, South Africa, fetal immune sex differences resulting in a 1.5–2-fold increased female susceptibility to intrauterine HIV infection. Viruses transmitted to females have lower replicative capacity (p = 0.0005) and are more type I interferon-resistant (p = 0.007) than those transmitted to males. Cord blood cells from females of HIV-uninfected sex-discordant twins are more activated (p = 0.01) and more susceptible to HIV infection in vitro (p = 0.03). Sex differences in outcome include superior maintenance of aviraemia among males (p = 0.007) that is not explained by differential antiretroviral therapy adherence. These data demonstrate sex-specific innate immune selection of HIV associated with increased female susceptibility to in utero infection and enhanced functional cure potential among infected males. Sex differences in the immune response to vaccines and infections have been well described in children and adults. Here the authors describe, in a cohort of 177 HIV-infected infants, innate immune sex differences in fetal life that increase female susceptibility to intrauterine HIV infection and increase the chances of subsequent HIV remission in infected males. [ABSTRACT FROM AUTHOR]

Abstract: A solvent extraction method was developed and validated for the determination of the antimalarial drug, artemether and its active metabolite dihydroartemisinin (DHA) in malaria patient plasma samples. An AB Sciex 4000 triple quadrupole mass spectrometer in the multiple reaction monitoring (MRM) mode was used for detection in the positive ionisation mode. Liquid–liquid extraction was followed by PFP liquid chromatography and tandem mass spectrometry. Stable isotope labelled artemether and DHA was used as internal standards. The calibration range was between 2.00 and 500ng/ml for both artemether and DHA during the original validation and the upper limit was lowered to 200ng/ml during a re-instatement validation, prior to sample analysis. The assay was used to measure artemether and DHA in human plasma samples, which were generated from a safety and efficacy clinical trial in Mbarara, Uganda; as well as for a pharmacokinetic interaction study between the antimalarial combination artemether/lumefantrine and combination antiretroviral therapy including nevirapine in HIV-infected adults. [Copyright &y& Elsevier]