Richard M. Donovan

Viral, Nutritional, and Bacterial Safety of Flash-Heated and Pretoria-Pasteurized Breast Milk to Prevent Mother-to-Child Transmission of HIV in Resource-Poor Countries A Pilot Study

Background:Heat-treated breast milk of HIV-positive mothers has potential to reduce vertical transmission. This study compared the impact of flash-heating (FH) and Pretoria pasteurization (PP) on HIV, nutrients, and antimicrobial properties in human milk. Methods:Milk samples were spiked with 1 × 108 copies/mL of clade C HIV-1 and treated with FH and PP. We measured HIV reverse transcriptase (RT) activity before and after heating (n = 5). Heat impact on vitamins A, B6, B12, and C; folate, riboflavin, thiamin, and antimicrobial proteins (lactoferrin and lysozyme) was assessed. Storage safety was evaluated by spiking with Escherichia coli or Staphylococcus aureus. Results:Both methods inactivated ≥3 logs of HIV-1. FH resulted in undetectable RT activity. Neither method caused significant decrease in any vitamin, although reductions in vitamins C and E were noted. Heat decreased immunoreactive lactoferrin (P < 0.05) but not the proportions of lactoferrin and lysozyme surviving digestion. FH seems to retain more antibacterial activity. Both treatments eliminated spiked bacteria. Conclusions:FH may be superior to PP in eliminating all viral activity; both methods retained nutrients and destroyed bacterial contamination. Heat-treated breast milk merits further study as a safe and practical infant feeding option for HIV-positive mothers in developing countries.

Flash-heat inactivation of HIV-1 in human milk: a potential method to reduce postnatal transmission in developing countries.

Background:Up to 40% of all mother-to-child transmission of HIV occurs by means of breast-feeding; yet, in developing countries, infant formula may not be a safe option. The World Health Organization recommends heat-treated breast milk as an infant-feeding alternative. We investigated the ability of a simple method, flash-heat, to inactivate HIV in breast milk from HIV-positive mothers. Methods:Ninety-eight breast milk samples, collected from 84 HIV-positive mothers in a periurban settlement in South Africa, were aliquoted to unheated control and flash-heating. Reverse transcriptase (RT) assays (lower detection limit of 400 HIV copies/mL) were performed to differentiate active versus inactivated cell-free HIV in unheated and flash-heated samples. Results:We found detectable HIV in breast milk samples from 31% (26 of 84) of mothers. After adjusting for covariates, multivariate logistic regression showed a statistically significant negative association between detectable virus in breast milk and maternal CD4+ T-lymphocyte count (P = 0.045) and volume of breast milk expressed (P = 0.01) and a positive association with use of multivitamins (P = 0.03). All flash-heated samples showed undetectable levels of cell-free HIV-1 as detected by the RT assay (P < 0.00001). Conclusions:Flash-heat can inactivate HIV in naturally infected breast milk from HIV-positive women. Field studies are urgently needed to determine the feasibility of in-home flash-heating breast milk to improve infant health while reducing postnatal transmission of HIV in developing countries.

The Gut Mucosal Viral Reservoir in HIV-Infected Patients Is Not the Major Source of Rebound Plasma Viremia following Interruption of Highly Active Antiretroviral Therapy

ABSTRACT Interruption of suppressive highly active antiretroviral therapy (HAART) in HIV-infected patients leads to increased HIV replication and viral rebound in peripheral blood. Effects of therapy interruption on gut-associated lymphoid tissue (GALT) have not been well investigated. We evaluated longitudinal changes in viral replication and emergence of viral variants in the context of T cell homeostasis and gene expression in GALT of three HIV-positive patients who initiated HAART during primary HIV infection but opted to interrupt therapy thereafter. Longitudinal viral sequence analysis revealed that a stable proviral reservoir was established in GALT during primary HIV infection that persisted through early HAART and post-therapy interruption. Proviral variants in GALT and peripheral blood mononuclear cells (PBMCs) displayed low levels of genomic diversity at all times. A rapid increase in viral loads with a modest decline of CD4+ T cells in peripheral blood was observed, while gut mucosal CD4+ T cell loss was severe following HAART interruption. This was accompanied by increased mucosal gene expression regulating interferon (IFN)-mediated antiviral responses and immune activation, a profile similar to those found in HAART-naive HIV-infected patients. Sequence analysis of rebound virus suggested that GALT was not the major contributor to the postinterruption plasma viremia nor were GALT HIV reservoirs rapidly replaced by HIV rebound variants. Our data suggest an early establishment and persistence of viral reservoirs in GALT with minimal diversity. Early detection of and therapy for HIV infection may be beneficial in controlling viral evolution and limiting establishment of diverse viral reservoirs in the mucosal compartment.

Intersubtype BF recombinants of HIV-1 in a population of injecting drug users in Argentina.

Summary:The presence of recombinant intersubtypes of HIV-1 in Argentina has been reported since the mid-1990s. In this study, sequences of a region of the gag, pol, and vpu genes of HIV-1 were analyzed in samples of 21 injection drug users (IDUs) residing in the suburbs of the city of Buenos Aires. Genomic characterization and identification of recombination sites were made comparing the 3 regions with reference isolation sequences of subtypes B, F, C, A, and B/F recombinants: CRF12_BF and non-CRF12_BF sequences. Subtype assignment of the analyzed segments was phylogenetically confirmed. All the samples turned out to be BF recombinants in at least 1 of the 3 studied genes. Twelve samples (57%) had the same pattern as the Argentinean CRF12_BF, whereas in the rest, the pattern differed in at least 1 of the 3 genes. The relation of these fragments to the CRF12_BF was phylogenetically verified. These results indicate the predominance of BF recombinants and the presence of a high percentage of sequences closely related to the CRF12_BF in the IDU population in Argentina and suggest a possible association between viral variants and the transmission route.

Human immunodeficiency virus-specific responses in adult Ugandans: patterns of cross-clade recognition.

ABSTRACT Human immunodeficiency virus (HIV) or AIDS is currently the leading cause of death in Uganda, with at least three HIV clades (subtypes) accounting for most new infections. Whether an effective vaccine formulated on viruses from a single clade will be able to protect against infection from other local clades remains unresolved. We examined the T-cell immune responses from a cohort of HIV-seropositive individuals in Uganda with predominantly clade A and D infections. Surprisingly, we observed similar frequencies of cross-clade T-cell responses to the gag, env, and nef regions. Our data suggest that the level of viral sequence variability between distinct HIV strains does not predict the degree of cross-clade responses. High sequence homologies were also observed between consensus peptides and sequences from viral isolates, supporting the use of consensus amino acid sequences to identify immunogenic regions in studies of large populations.

Antiretroviral therapy is associated with a decrease in unintegrated HIV-1 DNA in pediatric patients

SummaryGood markers for monitoring the efficacy of antiretroviral therapy in children do not currently exist. This study examined the effect of antiretroviral therapy on human immunodeficiency virus (HIV-1) unintegrated DNA (uDNA), integrated DNA (iDNA), percent uDNA, immune complex dissociated (ICD) p24 antigenemia, and plasma viral titer. Seven children were followed at therapy initiation and at ~3− and 10-month intervals. HIV-1 uDNA was detected in all children prior to start of therapy (average percent uDNA, 43%). At 3 months, the percent HIV uDNA decreased in all patients to an average of 18% (p = 0.01) and at 10 months decreased to an average of 1%. In contrast, the amount of HIV iDNA was relatively constant after initiation of therapy. ICD HIV p24 antigen was detected in all patients prior to therapy (average, 538 pg/ml). Over the study period, the ICD p24 antigen level decreased in three patients and remained relatively unchanged in four patients. Plasma cultures of HIV-1 were positive in only one of the seven patients prior to therapy. Among the methods evaluated, measurement of uDNA was the only parameter which reliable decreased after initiation of nucleoside therapy.