Diane Valéa

Human Milk-Derived B Cells: A Highly Activated Switched Memory Cell Population Primed to Secrete Antibodies

While secretory Abs have been extensively explored in human breast milk, the existence, features, and functions of B lymphocytes remain largely unexplored in this compartment. We analyzed breast milk and blood lymphocytes from 21 lactating women, including 12 HIV-1-infected mothers. Breast milk B cells displayed a phenotype of class-switched memory B cells, with few IgD+ memory and naive B cells. We observed that breast milk B lymphocytes bore a unique profile of adhesion molecules (CD44+, CD62L−, α4β7+/−, α4β1+). Higher percentages of activated B cells (CD38+), large-sized B cells, plasmablasts, and plasma cells (CD19+, CD20low/−, CD27high, CD138+) were found as compared with blood. This indicates that a significant proportion of breast milk B cells underwent terminal plasma cell differentiation. We also observed a higher frequency of cells secreting Ig spontaneously in breast milk. Among these cells, IgG-secreting cells predominated over IgA-secreting cells as measured by Ig ELISPOT assays. Specific Ab-secreting cells were investigated following polyclonal activation using the CD40L ligation. Finally, the detection of anti-HIV-1-secreting cells demonstrates the existence of B cells specific to HIV-1 Ag in breast milk from HIV-1-infected women. Breast milk B cells display a phenotype strikingly different from blood, are primed to secrete Abs, and have a mucosal homing profile similar to B cells located in gut-associated lymphoid tissue.

Comparison of the Generic HIV Viral Load assay with the Amplicor HIV-1 monitor v1.5 and Nuclisens HIV-1 EasyQ v1.2 techniques for plasma HIV-1 RNA quantitation of non-B subtypes: the Kesho Bora preparatory study

The implementation of cost effective HIV-1 RNA quantitation assays in resource-poor settings is of paramount importance for monitoring HV-1 infection. A study comparing the analytical performance of three HIV-1 RNA assays (Generic HIV Viral Load, Amplicor v1.5 and Nuclisens EasyQ v1.2) was performed on 160 plasma samples from 160 consecutive antiretroviral treatment naive HIV-1-infected pregnant women assessed for eligibility in the Kesho Bora trial aimed at prevention of mother-to-child transmission of HIV-1 in three African countries (Burkina Faso, Kenya and South Africa). Correlation and agreement of results of the three assays were assessed for plasma HIV-1 RNA quantitation in specimens harbouring mainly sub-subtype A1, subtype C, and circulating recombinant form (CRF) 02_AG and CRF06_cpx. Good degrees of correlation and agreement were observed between these HIV-1 RNA assays. However, nine (9/160, 5.6%) strains detectable with the Generic HIV Viral Load assay were not detected by either the Amplicor (n=7) or EasyQ (n=2) test. One strain (0.6%) was missed with the Generic HIV Viral Load assay. Further, concordantly positive plasma samples harbouring CRF02_AG and CRF06_cpx yielded significantly higher HIV-1 RNA concentrations when tested by Generic HIV Viral Load, as compared to Amplicor v1.5 (mean differences, +0.33 and +0.67 log(10) copies/ml; P=0.0004 and P=0.002, respectively). The Generic HIV Viral Load assay accurately quantified the majority of the non-B HIV-1 subtypes assessed in this study. Due to its low cost (approximately 10 US

Dried blood spot HIV-1 RNA quantification using open real-time systems in South Africa and Burkina Faso.

/test), this assay performed with open real-time PCR instruments is now used routinely in the Kesho Bora trial and may be recommended in other African settings.

Effect of Perinatal Zidovudine Prophylaxis on the Evolution of Cell-Free HIV-1 RNA in Breast Milk and on Postnatal Transmission

There is an urgent need to assess the accuracy/feasibility of using dried blood spots (DBS) for monitoring of HIV-1 viral load in resource-limited settings. A total of 892 DBS from HIV-1-positive pregnant women and their neonates enrolled in the Kesho Bora prevention of mother-to-child transmission trial conducted in Durban (South Africa) and Bobo-Dioulasso (Burkina Faso) between May 2005 and July 2008 were tested for HIV-1 RNA. The combination Nuclisens extraction method (BioMérieux)/Generic HIV Viral Load assay (Biocentric) was performed using one DBS (in Durban) versus 2 DBS (in Bobo-Dioulasso) on 2 distinct open real-time polymerase chain reaction instruments. DBS HIV-1 RNA results were compared with plasma HIV-1 RNA and HIV serology results used as the gold standards. The limits of detection of assays on DBS were 3100 and 1550 copies per milliliter in Durban and Bobo-Dioulasso, respectively. DBS HIV-1 RNA values correlated significantly with plasma levels (n = 327; R = 0.7351) and were uniformly distributed according to duration of DBS storage at −20°C (median duration, 280 days). For early infant diagnosis, the sensitivity and specificity were 100% (95% confidence interval: 97.2 to 100.0 and 96.5 to 100.0, respectively). HIV-1 viral load kinetics in DNase-pretreated DBS were similar to those obtained in plasma specimens among 13 patients receiving antiretroviral treatment. HIV-1 RNA findings from serial infant DBS collected prospectively (n = 164) showed 100% concordance with HIV serology at 18 months of life. Our findings strongly advocate the implementation of DBS HIV-1 RNA testing in remote areas from low-income and middle-income countries.

CD4 + T cells spontaneously producing human immunodeficiency virus type I in breast milk from women with or without antiretroviral drugs

Perinatal zidovudine (ZDV) prophylaxis decreases rates of perinatal transmission of human immunodeficiency virus type 1 (HIV-1). Its relationship with levels of HIV-1 RNA in breast milk and postnatal transmission in breast-fed African children is unknown. At day 8 after delivery, levels of HIV-1 RNA in breast milk from 28 women who transmitted HIV-1 (Ts) postnatally and from 130 women who did not transmit HIV-1 (NTs) were lower for women receiving ZDV than for women receiving placebo. Levels of HIV-1 RNA in breast milk remained low over time in NTs but increased by 8-16-fold in Ts treated with ZDV from baseline to days 45/90 after delivery. Levels of HIV-1 RNA in breast milk at day 8 after delivery and the increase in levels of HIV-1 RNA in breast milk from day 8 to days 45/90 after delivery were independently associated with postnatal transmission. An increase in the levels of HIV-1 RNA in breast milk from day 8 to 45 after delivery was associated with maternal ZDV prophylaxis. The rebound in levels of HIV-1 RNA in breast milk after discontinuation of maternal antiretrovirals needs to be further explored--it may justify prolonging antiretroviral prophylaxis during the entire breast-feeding period.

Maternal HIV-1 Disease Progression 18–24 Months Postdelivery According to Antiretroviral Prophylaxis Regimen (Triple-Antiretroviral Prophylaxis During Pregnancy and Breastfeeding vs Zidovudine/Single-Dose Nevirapine Prophylaxis): The Kesho Bora Randomized Controlled Trial

BackgroundTransmission of human immunodeficiency virus type 1 (HIV-1) through breast-feeding may involve both cell-free and cell-associated virus. This latter viral reservoir remains, however, to be fully explored. CD4+ T cell-associated virus production in breast milk was therefore investigated.MethodsThe ex vivo spontaneous production of HIV-1 antigen and HIV-1 RNA by CD4+ T cells was measured in paired blood and breast milk samples from 15 HIV-1 infected women treated or not with antiretroviral drugs. Spontaneous antigen secreting cells (HIV-1-AgSCs) from breast milk and blood were enumerated by an ELISpot assay, and cell-associated HIV-1 RNA was quantified by real-time PCR in supernatants of CD4+ T cells cultured for 18 hours without addition of polyclonal activators.ResultsAmong the CD4+ T cells present in breast milk, memory cells expressing high levels of cell-surface activation markers were predominant. Spontaneous HIV-1-AgSCs were detected and enumerated in the breast milk of all 15 women, with a median number of 13.0 and 9.5 HIV-1- AgSCs/106 CD4+ T cells in aviremic (n = 7) and viremic (n = 8) women, respectively. Cell- associated HIV-1 RNA was detected in cell-free supernatants from 4/7 aviremic and 5/8 viremic individuals at median levels of 190 and 245 copies/ml, respectively.ConclusionsActivated CD4+ T cells producing HIV-1 are detected in the breast milk of untreated individuals as well as those receiving highly active antiretroviral therapy. This finding strongly suggests that HIV-1 replication occurs in latently infected CD4+ T cells that, upon spontaneous activation, revert to productively infected cells. These cells might be responsible for a residual breast milk transmission despite maternal highly active antiretroviral therapy.

In-house HIV-1 RNA real-time RT-PCR assays: principle, available tests and usefulness in developing countries

BACKGROUND Antiretroviral (ARV) prophylaxis effectively reduces mother-to-child transmission of human immunodeficiency virus type 1 (HIV). However, it is unclear whether stopping ARVs after breastfeeding cessation affects maternal HIV disease progression. We assessed 18-24-month postpartum disease progression risk among women in a randomized trial assessing efficacy and safety of prophylactic maternal ARVs. METHODS From 2005 to 2008, HIV-infected pregnant women with CD4(+) counts of 200-500/mm(3) were randomized to receive either triple ARV (zidovudine, lamivudine, and lopinavir/ritonavir during pregnancy and breastfeeding) or AZT/sdNVP (zidovudine until delivery with single-dose nevirapine without postpartum prophylaxis). Maternal disease progression was defined as the combined endpoint of death, World Health Organization clinical stage 4 disease, or CD4(+) counts of <200/mm(3). RESULTS Among 824 randomized women, 789 had at least 1 study visit after cessation of ARV prophylaxis. Following delivery, progression risk up to 24 months postpartum in the triple ARV arm was significantly lower than in the AZT/sdNVP arm (15.7% vs 28.3%; P = .001), but the risks of progression after cessation of ARV prophylaxis (rather than after delivery) were not different (15.0% vs 13.8% 18 months after ARV cessation). Among women with CD4(+) counts of 200-349/mm(3) at enrollment, 24.0% (95% confidence interval [CI], 15.7-35.5) progressed with triple ARV, and 23.0% (95% CI, 17.8-29.5) progressed with AZT/sdNVP, whereas few women in either arm (<5%) with initial CD4(+) counts of ≥350/mm(3) progressed. CONCLUSIONS Interrupting prolonged triple ARV prophylaxis had no effect on HIV progression following cessation (compared with AZT/sdNVP). However, women on triple ARV prophylaxis had lower progression risk during the time on triple ARV. Given the high rate of progression among women with CD4(+) cells of <350/mm(3), ARVs should not be discontinued in this group. CLINICAL TRIALS REGISTRATION ISRCTN71468410.

Detection of a large T-cell reservoir able to replicate HIV-1 actively in breast milk

The principle of currently available licensed HIV-1 RNA assays is based on real-time technologies that continuously monitor the fluorescence emitted by the amplification products. Besides these assays, in-house quantitative (q) real-time reverse transcription (RT)-PCR (RT-qPCR) tests have been developed and evaluated particularly in developing countries, for two main reasons. First, affordable and generalized access to HIV-1 RNA viral load is urgently needed in the context of expected universal access to prevention and antiretroviral treatment programs in these settings. Second, since many non-B subtypes, circulating recombinant forms and unique recombinant forms circulate in these areas, in-house HIV-1 RNA RT-qPCR assays are ideal academic tools to thoroughly evaluate the impact of HIV-1 genetic diversity on the accuracy of HIV-1 RNA quantification, as compared with licensed techniques. To date, at least 15 distinct in-house assays have been designed. They differ by their chemistry and the HIV-1 target sequence (located in gag, Pol-IN or LTR gene). Analytical performances of the tests that have been extensively evaluated appear at least as good as (or even better than) those of approved assays, with regard to HIV-1 strain diversity. Their clinical usefulness has been clearly demonstrated for early diagnosis of pediatric HIV-1 infection and monitoring of highly active antiretroviral therapy efficacy. The LTR-based HIV-1 RNA RT-qPCR assay has been evaluated by several groups under the auspices of the Agence Nationale de Recherches sur le SIDA et les hépatites virales B et C. It exists now as a complete standardized commercial test.

Low Prevalence Rate of Indeterminate Serological Human Immunodeficiency Virus Results among Pregnant Women from Burkina Faso, West Africa

In breast milk and paired blood samples of nine HIV-1-infected lactating women, we undertook a study to detect a CD4 T-cell reservoir and to investigate its capacity to enter viral production after activation. Breast milk-infected CD4 T cells have a greater capacity to produce viral particles actively than blood CD4 T cells. This observation may explain the apparent paradox of a transmissible viral infection from a body fluid with a low viral concentration.

P07-11 LB. Impact of highly active antiretroviral therapy on cell-free and cell-associated HIV-1 in cervicovaginal secretions and blood

ABSTRACT Rapid human immunodeficiency virus (HIV) antibody tests have been adopted into national guidelines for HIV testing in many countries in sub-Saharan Africa. One goal of HIV rapid testing is to minimize the occurrence of indeterminate results. From January 2005 to December 2007, plasma (or serum) samples from pregnant women in Bobo-Dioulasso (Burkina Faso, West Africa) were screened for HIV by using two rapid tests (the Determine HIV1/2 test [Abbott] and Genie II HIV-1/HIV-2 [Bio-Rad]) through a sequential algorithm prior to enrollment of HIV-1-infected women in a prevention of mother-to-child transmission (PMTCT) trial (WHO/ANRS 1289 Kesho Bora trial). Samples exhibiting indeterminate results (Determine positive and Genie II negative) were further tested with a fourth-generation HIV enzyme immunoassay (EIA) (Murex HIV Ag/Ab combination in 2005 and 2006 and Vironostika HIV Uni-Form II Ag/Ab in 2007). If positive, they were finally assessed for HIV-1 RNA (Generic HIV-1 RNA viral load assay; Biocentric). From a total of 44,653 samples tested, 597 (1.3%) showed indeterminate results. Of these, 367 could be analyzed by EIA. Only 15 (15/367, 4.1%) samples were found EIA reactive. Of these, 11 could be tested for HIV-1 RNA. All were HIV-1 RNA negative. In our clinical practice, pregnant women with such indeterminate results are now reassured during posttest counseling that they are very unlikely to be infected with HIV-1. As a consequence, such women with indeterminate results can reliably be considered negative when urgent clinical decisions (such as providing PMTCT prophylaxis) need to be taken.