Laboratory-based performance evaluation of PIMA CD4+ T-lymphocyte count point-of-care by lay-counselors in Kenya.

BACKGROUND: CD4+ T-lymphocyte count testing at the point-of-care (POC) may improve linkage to care of persons diagnosed with HIV-1 infection, but the accuracy of POC devices when operated by lay-counselors in the era of task-shifting is unknown. We examined the accuracy of Alere's Pima™ POC device on both capillary and venous blood when performed by lay-counselors and laboratory technicians. METHODS: In Phase I, we compared the perfomance of POC against FACSCalibur™ for 280 venous specimens by laboratory technicians. In Phase II we compared POC performance by lay-counselors versus laboratory technicians using 147 paired capillary and venous specimens, and compared these to FACSCalibur™. Statistical analyses included Bland-Altman analyses, concordance correlation coefficient, sensitivity, and specificity at treatment eligibility thresholds of 200, 350, and 500cells/µl. RESULTS: Phase I: POC sensitivity and specificity were 93.0% and 84.1% at 500cells/µl, respectively. Phase II: Good agreement was observed for venous POC results from both lay-counselors (concordance correlation coefficient (CCC)=0.873, bias -86.4cells/µl) and laboratory technicians (CCC=0.920, bias -65.7cells/µl). Capillary POC had good correlation: lay-counselors (CCC=0.902, bias -71.2cells/µl), laboratory technicians (CCC=0.918, bias -63.0cells/µl). Misclassification at the 500 cells/µl threshold for venous blood was 13.6% and 10.2% for lay-counselors and laboratory technicians and 12.2% for capillary blood in both groups. POC tended to under-classify the CD4 values with increasingly negative bias at higher CD4 values. CONCLUSIONS: Pima™ results were comparable to FACSCalibur™ for both venous and capillary specimens when operated by lay-counselors. POC CD4 testing has the potential to improve linkage to HIV care without burdening laboratory technicians in resource-limited settings.

Establishment of reference intervals during normal pregnancy through six months postpartum in western Kenya.

BACKGROUND: Pregnancy is associated with changes in hematological and biochemistry values, yet there are no African reference intervals for clinical management of pregnant women. We sought to 1) develop laboratory reference intervals during pregnancy and up to 24 weeks postpartum and 2) determine the proportion of women in a previous clinical trial who would be misclassified as having out-of-range values using reference intervals from a United States (U.S.) population. METHODS AND FINDINGS: This was a longitudinal sub-study of 120 clinically healthy, HIV-uninfected, self-selected pregnant women seeking antenatal care services at either of two public hospitals in western Kenya. Blood specimens were obtained from consented women at gestational ages 28 and 36 weeks and at 2, 6, 14 and 24 weeks postpartum. Median and 95% reference intervals were calculated for immune-hematological and biochemistry parameters and compared to reference intervals from a Kenyan and United States (U.S.) population, using Wilcoxon tests. Differences with p≤0.05 were considered significant. Some hematological parameters, including hemoglobin and neutrophils showed significant variations compared to reference intervals for non-pregnant women. Hemoglobin values were significantly lower during pregnancy but were comparable to the values in non-pregnant women by 6 weeks postpartum. CD4, CD8 and platelets were significantly elevated in early postpartum but declined gradually, reaching normal levels by 24 weeks postpartum. Using the new hemoglobin reference levels from this study to estimate prevalence of 'out of range' values in a prior Kisumu research cohort of pregnant/postpartum women, resulted in 0% out of range values, in contrast to 96.3% using US non-pregnant reference values. CONCLUSION: There were substantial differences in U.S. and Kenyan values for immune-hematological parameters among pregnant/postpartum women, specifically in red blood cell parameters in late pregnancy and 2 weeks postpartum. Use of U.S. reference intervals markedly increases likelihood of out of range values, highlighting the need for suitable locally developed reference intervals.

Clinical Evaluation of the BD FACSPresto™ Near-Patient CD4 Counter in Kenya.

BACKGROUND: The BD FACSPresto™ Near-Patient CD4 Counter was developed to expand HIV/AIDS management in resource-limited settings. It measures absolute CD4 counts (AbsCD4), percent CD4 (%CD4), and hemoglobin (Hb) from a single drop of capillary or venous blood in approximately 23 minutes, with throughput of 10 samples per hour. We assessed the performance of the BD FACSPresto system, evaluating accuracy, stability, linearity, precision, and reference intervals using capillary and venous blood at KEMRI/CDC HIV-research laboratory, Kisumu, Kenya, and precision and linearity at BD Biosciences, California, USA. METHODS: For accuracy, venous samples were tested using the BD FACSCalibur™ instrument with BD Tritest™ CD3/CD4/CD45 reagent, BD Trucount™ tubes, and BD Multiset™ software for AbsCD4 and %CD4, and the Sysmex™ KX-21N for Hb. Stability studies evaluated duration of staining (18-120-minute incubation), and effects of venous blood storage <6-24 hours post-draw. A normal cohort was tested for reference intervals. Precision covered multiple days, operators, and instruments. Linearity required mixing two pools of samples, to obtain evenly spaced concentrations for AbsCD4, total lymphocytes, and Hb. RESULTS: AbsCD4 and %CD4 venous/capillary (N = 189/ N = 162) accuracy results gave Deming regression slopes within 0.97-1.03 and R2 ≥0.96. For Hb, Deming regression results were R2 ≥0.94 and slope ≥0.94 for both venous and capillary samples. Stability varied within 10% 2 hours after staining and for venous blood stored less than 24 hours. Reference intervals results showed that gender-but not age-differences were statistically significant (p<0.05). Precision results had <3.5% coefficient of variation for AbsCD4, %CD4, and Hb, except for low AbsCD4 samples (<6.8%). Linearity was 42-4,897 cells/µL for AbsCD4, 182-11,704 cells/µL for total lymphocytes, and 2-24 g/dL for Hb. CONCLUSIONS: The BD FACSPresto system provides accurate, precise clinical results for capillary or venous blood samples and is suitable for near-patient CD4 testing. TRIAL REGISTRATION: ClinicalTrials.gov NCT02396355.

Anemia and Red Blood Cell Abnormalities in HIV-Infected and HIV-Exposed Breastfed Infants: A Secondary Analysis of the Kisumu Breastfeeding Study.

BACKGROUND: Anemia results in increased morbidity and mortality, underscoring the need to better understand its pathophysiology amongst HIV-exposed and infected children in sub-Saharan Africa, the region where most infant HIV exposure and infections occur. METHODS: This analysis used samples obtained from children in the Kisumu Breastfeeding Study (KiBS). KiBS was a longitudinal phase IIB, open-label, one-arm clinical trial, designed to investigate the safety, tolerability and effectiveness of a maternal triple-antiretroviral (ARV) regimen for prevention of mother-to-child transmission (PMTCT) of HIV, during late pregnancy and early infancy while breastfeeding. Blood samples from 482 children were obtained at birth, 2, 6, 10 and 14 weeks and 6, 9, 12, 18 and 24 months. Severity of anemia was graded using the NIH Division of AIDS (DAIDS) toxicity tables. We describe the proportion of children with anemia and anomalies in red blood cell parameters at various time points over 24 months and compare rates of anemia between HIV-infected and HIV-uninfected children and by mothers' ARV regimen and infant malaria infection. RESULTS: The proportion of children with anemia significantly increased after the breastfeeding period in both HIV-infected and HIV-uninfected children with higher proportion among HIV-infected children compared to HIV-uninfected children (RR: 1.72; CI: 1.22-2.44, p = 0.002). Maternal triple-antiretroviral regimen was not associated with infant anemia (p = 0.11). There was no significant difference in mean hemoglobin between HIV-uninfected children with and without malaria at each time point except at 24 months. CONCLUSION: A relatively lower proportion of children with severe anemia during the breastfeeding period suggest that exposure to mother's triple antiretroviral combinations through breast milk, posed minimal risk of hematologic toxicity.

Neutropenia in HIV-Infected Kenyan Women Receiving Triple Antiretroviral Prophylaxis to Prevent Mother-to-Child HIV Transmission Is Not Associated with Serious Clinical Sequelae.

BACKGROUND: Absolute neutrophil counts (ANCs) are lower in East African adults. To assess the impact of lower ANCs, we reviewed data from HIV-infected Kenyan women receiving antiretroviral therapy antepartum and postpartum. METHODS: The Kisumu Breastfeeding Study (KiBS) participants received an antiretroviral regimen from 34 weeks' gestation through 6 months postpartum. Measured ANCs and subsequent illnesses were reviewed. Adverse events (AEs) potentially attributable to neutropenia were identified, and ANCs were graded using the 2004 Division of AIDS table for Grading the Severity of AEs. RESULTS: Among 478 women with ≥1 postpartum ANC measured, 298 (62.1%) women met criteria for an AE (<1.3 × 10(9) cells/L). Of those, 38 (12.5%) women experienced a nonlife-threatening illness potentially attributable to neutropenia. CONCLUSION: More than half of KiBS women met criteria for neutropenia. The mild clinical experience of most participants with low ANCs supports that these values might be typical for this population and may not result in adverse clinical sequelae.

Nevirapine-associated hepatotoxicity and rash among HIV-infected pregnant women in Kenya.

BACKGROUND: Few studies have evaluated the risk of nevirapine (NVP)-associated hepatotoxicity among HIV-infected pregnant women with a CD4 count ≥250 cells/mm(3). METHODS: We enrolled HIV-infected pregnant Kenyan women who initiated triple antiretroviral therapy (ART) at 34 weeks gestation. We compared the rates of severe hepatotoxicity (grades 3-4 hepatotoxicity) and rash-associated hepatotoxicity (rash with ≥grade 2 hepatotoxicity) with NVP and nelfinavir (NFV), respectively. RESULTS: We initiated triple ART in 522 pregnant women; severe hepatotoxicity and rash-associated hepatotoxicity occurred in 14 (3%) and 9 (2%) women, respectively. Women who initiated NVP had higher rates of severe hepatotoxicity (5% vs 1%; P = .03) and rash-associated hepatotoxicity (4% vs 0%; P = .003) when compared with NFV. Among women who initiated NVP (n = 254), a baseline CD4 count ≥250 cells/mm(3) was not associated with severe hepatotoxicity (5% vs 3%; P = .52) or rash-associated hepatotoxicity (4% vs 3%; P = .69). CONCLUSION: Nevirapine use but not CD4 count ≥250 cells/mm(3) was associated with hepatotoxicity.