Lymphocyte subsets in human immunodeficiency virus type 1-infected and uninfected children in Nairobi

Common hematological parameters reference intervals for apparently healthy pregnant and non-pregnant women of South Wollo Zone, Amhara Regional State, Northeast Ethiopia

Background

Hematological reference intervals (RIs) are affected by inherent variables like age, sex, genetic background, environment, diet and certain circumstances such as pregnancy signifying the need for population specific values. This study was designed to establish RIs for common hematological parameters of apparently healthy pregnant and non-pregnant women from Northeast Ethiopia.

Method

This community based cross-sectional study recruited 600 pregnant and non-pregnant women in South Wollo Zone, Northeast Ethiopia from June to August 2019. Complete blood count was performed for eligible participants using Mindary BC-3000 plus hematology analyzer. The mean, median, and 2.5^th and 97.5^th percentile reference limits with 90% CI were determined using SPSS version 23.

Result

The established selected 2.5^th–97.5^th percentiles RIs for pregnant women were: WBC: 4.0–13.2x10⁹/L; RBC: 3.45–4.67x10¹²/L; Hgb: 10.1–13.7g/dL; HCT: 33.5–46.5%; MCV: 85-104fL; MCH: 27.5–33.0pg; MCHC: 30.3–33.7g/dL and Platelet count: 132-373x10⁹/L. The respective values for non-pregnant women were 3.6–10.3; 4.44–5.01; 12.4–14.3; 38.4–50.1; 86–102; 27.1–32.4, 30.4–34.1, 173–456. A statistically significant difference between pregnant and non-pregnant women was noted in all hematological parameters except MCHC. The mean and median value of WBC count, MCV, MPV and PDW increased, whereas mean values of HCT and Platelet count decreased as gestational period advances.

Conclusion

The observed difference from other studies signify the necessity for using trimester specific RIs and separate RI for pregnant and non-pregnant women. Thus, we recommend the health facilities in the study area to utilize the currently established RIs for pregnant and non-pregnant women for better care.

Variation of B cell subsets with age in healthy Malawians

Although a number of previous studies have shown that different lymphocyte subsets, including B cells, vary with age, how different B cell subsets vary with age in Malawian population has not been shown before. We recruited Malawian participants of different ages and analyzed their venous blood samples for different B cell subsets. We found that both percentage and absolute counts of B cells varied with age peaking in the 7 to 12 months age group. Proportion of naïve B cells was highest in neonates and decreased with age whereas the percentage of memory B cells was lowest in neonates and increased with age. When we zeroed in on the age band within which the proportion of B cells was highest, both classical and activated memory B cells increased with age and the naïve followed the opposite trend. These results provide additional knowledge in our understanding of the dynamics of B cell subsets in individuals of a specific ethnicity as they age.

Comparison of Lymphocyte Subset Populations in Children From South Africa, US and Europe

Background: Typically, African healthcare providers use immunological reference intervals adopted from Europe and the United States (US). This may be inappropriate in a setting with many differences including exposure to different environmental stimuli and pathogens. We compared immunological reference intervals for children from Europe and the US with South African children to explore whether healthy children living in settings with high rates of infectious diseases have different baseline immunological parameters. Methodology: Blood was taken from 381 HIV-uninfected children aged between 2 weeks and 13 years of age from a Child Wellness Clinic in an informal settlement in Cape Town to establish local hematological and lymphocyte reference intervals for South African children. Flow-cytometry quantified percentage and absolute counts of the B-cells, NK-cells, and T-cells including activated, naïve, and memory subsets. These parameters were compared to three separate studies of healthy children in Europe and the US. Results: Increased activated T-cells, and natural killer cells were seen in the younger age-groups. The main finding across all age-groups was that the ratio of naïve/memory CD4 and CD8 T-cells reached a 1:1 ratio around the first decade of life in healthy South African children, far earlier than in resource-rich countries, where it occurs around the fourth decade of life. Conclusions: This is the largest data set to date describing healthy children from an African environment. These data have been used to create local reference intervals for South African children. The dramatic decline in the naïve/memory ratio of both CD4 and CD8 T-cells alongside increased activation markers may indicate that South African children are exposed to a wider range of environmental pathogens in early life than in resource-rich countries. These marked differences illustrate that reference intervals should be relevant to the population they serve. The implications for the developing pediatric immune system requires further investigation.

Haematological and immunological reference intervals for adult population in the state of Amhara, Ethiopia

OBJECTIVE

Reference intervals (RIs) currently being used in Ethiopia are derived from western populations. Thus, this study aimed to establish locally derived haematological and immunological RIs.

METHOD

The study was conducted in Amhara State, Ethiopia with a total of 967 (55.2% males) participants. 56.9% of males and 43.1% of females were eligible for haematological and immunological RI determination. A non-parametric test was used for the determination of upper (97.5th percentile) and lower (2.5th percentile) reference interval limits with 95% CI. The Harris and Boyd Rule was used to determine the need of partitioning of reference intervals based on gender.

RESULT

The established 95% reference intervals (2.5th-97.5th percentile) were: for WBC: 3-11.2 × 10⁹ /l; for platelet: 90-399 × 10⁹ /l; for RBC: 4-6 × 10¹² /l for males and 3.5-5.6 × 10¹² /l for females; for haemoglobin: (Hgb) 12-18.9 g/dl for males and 10.7-17.5 g/dl for females; for PCV: 35.7-55.3% for males and 32.2-50.1% for females; for CD4: 400-1430 × 10⁹ /l for males and 466-1523 × 10⁹ /l for females; for CD4 percentage: 18-49.1% for males and 21.3-52.9% for females; for MCV: 81-100 fl; for MCH: 25.3-34.6 pg; MCHC: 28.8-36.9%; for RDW: 11.6-15.4% and for MPV: 8-12.3 fl. Males had significantly higher RBC, Hgb and PCV than females. CD4 counts and CD4 percentage were significantly higher in females.

CONCLUSION

The reference intervals established in this study differ from others and thus should be used for the interpretation of laboratory results in diagnosis and safety monitoring in clinical trials in Amhara.

Early versus late BCG vaccination in HIV-1-exposed infants in Uganda: study protocol for a randomized controlled trial

Background

Bacillus Calmette-Guérin (BCG) vaccination may have nonspecific effects, i.e., effects on childhood morbidity and mortality that go beyond its effect on the risk of childhood tuberculosis (TB). Though the available scientific literature is mostly from observational studies, and is fraught with controversy, BCG vaccination at birth may protect infants in high-mortality populations against serious infections other than TB. Yet, other studies indicate that giving BCG later in infancy may modify immune responses to non-TB antigens and potentially enhance immunity, potentially also against tuberculosis (TB). It is unclear whether BCG vaccination very early in life offers adequate protection against TB and other infections among HIV-1-exposed children because even those who remain uninfected with HIV-1 show signs of impaired immunocompetence early in infancy. This study will compare BCG vaccination at birth with BCG vaccination at 14 weeks of age in HIV-1-exposed infants.

Methods

This is an individually randomized controlled trial in 2200 HIV-1-exposed infants. The intervention is BCG vaccination within 24 h of birth while the comparator is BCG given at 14 weeks of age. The study co-primary outcomes are severe illness in the first 14 weeks of life, and production of tumor necrosis factor, interleukin (IL)-1β, IL-6 and interferon-γ in response to mycobacterial and nonmycobacterial antigens. The study is being conducted in three health centers in Uganda.

Discussion

A well-timed BCG vaccination could have important nonspecific effects in HIV-1-exposed infants. This trial could inform the development of appropriate timing of BCG vaccination for HIV-1-exposed infants.

Trial registration

ClinicalTrials.gov, identifier: NCT02606526. Registered on 12 November 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-1881-z) contains supplementary material, which is available to authorized users.

Differences in virologic and immunologic response to antiretroviral therapy among HIV-1-infected infants and children

BACKGROUND

Virologic and immunologic responses to antiretroviral treatment (ART) in infants may differ from older children due to immunologic, clinical, or epidemiologic characteristics.

METHODS

Longitudinal ART responses were modeled and compared in HIV-infected infants and children enrolled in cohorts in Nairobi, Kenya. Participants were enrolled soon after HIV diagnosis, started on ART, and followed for 2 years. Viral load decline was compared between infant and child cohorts using a nonlinear mixed effects model and CD4% reconstitution using a linear mixed effects model.

RESULTS

Among 121 infants, median age at ART was 3.9 months; among 124 children, median age was 4.8 years. At baseline, viral load was higher among infants than children (6.47 vs. 5.91 log10 copies/ml, P < 0.001). Infants were less likely than children to suppress viral load to less than 250 copies/ml following 6 months of ART (32% infants vs. 73% children, P < 0.0001). CD4% was higher at baseline in infants than children (19 vs. 7.3%, P < 0.001). Older children had more rapid CD4% reconstitution than infants, but failed to catch up to infant CD4%.

CONCLUSION

Despite substantially higher CD4% at ART initiation, viral suppression was significantly slower among infants than older children. New strategies are needed to optimize infant outcomes on ART.

Hematological Indices in Malian Children Change Significantly During a Malaria Season and with Increasing Age: Implications for Malaria Epidemiological Studies

Standard hematological indices are commonly used in malaria epidemiological studies to measure anemia prevalence and calculate blood parasite densities. In Africa, few studies have investigated how these indices change during a malaria transmission season and with increasing age. To address these knowledge gaps, we collected blood from 169 healthy Malian children aged 3-12 years before (May 2010) and after (January 2011) a transmission season. Red blood cell (RBC) count, hemoglobin (Hb) level, hematocrit (Ht), white blood cell (WBC) count, and WBC subsets were measured in paired blood samples, and the data were stratified by month (May, January) and age group (3-5, 6-8, and 9-12 years). From May to January, RBC count (4.53-4.70 × 10(6)/μL; P < 0.0001), Hb level (11.5-11.9 g/dL; P < 0.0001), and Ht (37.1-39.2%; P < 0.0001) increased, and WBC count (6.46-5.96 × 10(3)/μL; P = 0.0006) decreased. From May to January, the prevalence of WBC subsets also changed: 35-43% neutrophils, 6.5-7.6% monocytes, and 53-45% lymphocytes (P < 0.001). These seasonal changes were not associated with the number of malaria episodes experienced in the interim or the presence of RBC polymorphisms. In May, Hb (11.2, 11.4, and 11.8 g/dL; P = 0.0013) and Ht (36.5%, 36.7%, and 38.1%; P = 0.0154) increased and WBC count (8.04, 6.43, and 5.76 × 10(3)/μL; P < 0.0001) decreased with age group; similar differences were observed in January. These data suggest that season- and age-based reference values for hematological indices are needed to better estimate anemia prevalence and parasite density in malaria epidemiological studies.

Treatment Failures and Excess Mortality Among HIV-Exposed, Uninfected Children With Pneumonia

BACKGROUND

Human immunodeficiency virus (HIV)-exposed, uninfected (HIV-EU) children are at increased risk of infectious illnesses and mortality compared with children of HIV-negative mothers (HIV-unexposed). However, treatment outcomes for lower respiratory tract infections among HIV-EU children remain poorly defined.

METHODS

We conducted a hospital-based, prospective cohort study of N = 238 children aged 1-23 months with pneumonia, defined by the World Health Organization. Children were recruited within 6 hours of presentation to a tertiary hospital in Botswana. The primary outcome--treatment failure at 48 hours--was assessed by an investigator blinded to HIV exposure status.

RESULTS

Median age was 6.0 months; 55% were male. One hundred fifty-three (64%) children were HIV-unexposed, 64 (27%) were HIV-EU, and 20 (8%) were HIV-infected; the HIV exposure status of 1 child could not be established. Treatment failure at 48 hours occurred in 79 (33%) children, including in 36 (24%) HIV-unexposed, 30 (47%) HIV-EU, and 12 (60%) HIV-infected children. In multivariable analyses, HIV-EU children were more likely to fail treatment at 48 hours (risk ratio [RR]: 1.83, 95% confidence interval [CI]: 1.27-2.64, P = .001) and had higher in-hospital mortality (RR: 4.31, 95% CI: 1.44-12.87, P = .01) than HIV-unexposed children. Differences in outcomes by HIV exposure status were observed only among children under 6 months of age. HIV-EU children more frequently received treatment with a third-generation cephalosporin, but this did not reduce the risk of treatment failure in this group.

CONCLUSIONS

HIV-EU children with pneumonia have higher rates of treatment failure and in-hospital mortality than HIV-unexposed children during the first 6 months of life. Treatment with a third-generation cephalosporins did not improve outcomes among HIV-EU children.

Cost-effectiveness of first-line antiretroviral therapy for HIV-infected African children less than 3 years of age

Background:

The International Maternal, Pediatric, and Adolescent Clinical Trials P1060 trial demonstrated superior outcomes for HIV-infected children less than 3 years old initiating antiretroviral therapy (ART) with lopinavir/ritonavir compared to nevirapine, but lopinavir/ritonavir is four-fold costlier.

Design/methods:

We used the Cost-Effectiveness of Preventing AIDS Complications (CEPAC)-Pediatric model, with published and P1060 data, to project outcomes under three strategies: no ART; first-line nevirapine (with second-line lopinavir/ritonavir); and first-line lopinavir/ritonavir (second-line nevirapine). The base-case examined South African children initiating ART at age 12 months; sensitivity analyses varied all key model parameters. Outcomes included life expectancy, lifetime costs, and incremental cost-effectiveness ratios [ICERs; dollars/year of life saved ($/YLS)]. We considered interventions with ICERs less than 1× per-capita gross domestic product (South Africa: $7500)/YLS as ‘very cost-effective,’ interventions with ICERs below 3× gross domestic product/YLS as ‘cost-effective,’ and interventions leading to longer life expectancy and lower lifetime costs as ‘cost-saving’.

Results:

Projected life expectancy was 2.8 years with no ART. Both ART regimens markedly improved life expectancy and were very cost-effective, compared to no ART. First-line lopinavir/ritonavir led to longer life expectancy (28.8 years) and lower lifetime costs ($41 350/person, from lower second-line costs) than first-line nevirapine (27.6 years, $44 030). First-line lopinavir/ritonavir remained cost-saving or very cost-effective compared to first-line nevirapine unless: liquid lopinavir/ritonavir led to two-fold higher virologic failure rates or 15-fold greater costs than in the base-case, or second-line ART following first-line lopinavir/ritonavir was very ineffective.

Conclusions:

On the basis of P1060 data, first-line lopinavir/ritonavir leads to longer life expectancy and is cost-saving or very cost-effective compared to first-line nevirapine. This supports WHO guidelines, but increasing access to pediatric ART is critical regardless of the regimen used.

Impact of elevated maternal HIV viral load at delivery on T-cell populations in HIV exposed uninfected infants in Mozambique

Background

HIV-uninfected infants born to HIV-infected mothers (HIV-exposed uninfected, HEU) have been described to have immune alterations as compared to unexposed infants. This study sought to characterize T-cell populations after birth in HEU infants and unexposed infants living in a semirural area in southern Mozambique.

Methods

Between August 2008 and June 2009 mother-infant pairs were enrolled at the Manhiça District Hospital at delivery into a prospective observational analysis of immunological and health outcomes in HEU infants. Infants were invited to return at one month of age for a clinical examination, HIV DNA-PCR, and immunophenotypic analyses. The primary analysis sought to assess immunological differences between HEU and unexposed groups, whereas the secondary analysis assessed the impact of maternal HIV RNA viral load in the HEU group. Infants who had a positive HIV DNA-PCR test were not included in the analysis.

Results

At one month of age, the 74 HEU and the 56 unexposed infants had similar median levels of naïve, memory and activated CD8 and CD4 T-cells. Infant naïve and activated CD8 T-cells were found to be associated with maternal HIV-RNA load at delivery. HEU infants born to women with HIV-RNA loads above 5 log₁₀ copies/mL had lower median levels of naïve CD8 T-cells (p = 0.04), and higher median levels of memory CD8 T-cells, (p = 0.014).

Conclusions

This study suggests that exposure to elevated maternal HIV-RNA puts the infant at higher risk of having early T-cell abnormalities. Improving prophylaxis of mother to child HIV programs such that more women have undetectable viral load is crucial to decrease vertical transmission of HIV, but may also be important to reduce the consequences of HIV virus exposure in HEU infants.

The impact of HIV exposure and maternal Mycobacterium tuberculosis infection on infant immune responses to bacille Calmette-Guérin vaccination

Objective:

The objective of this study is to assess the effect of maternal HIV and Mycobacterium tuberculosis (Mtb) infection on cellular responses to bacille Calmette-Guérin (BCG) immunization.

Design:

A mother–infant cohort study.

Methods:

Samples were collected from mother–infant pairs at delivery. Infants were BCG-vaccinated at 6 weeks of age and a repeat blood sample was collected from infants at 16 weeks of age. BCG-specific T-cell proliferation and intracellular cytokine expression were measured by flow cytometry. Secreted cytokines and chemokines in cell culture supernatants were analysed using a Multiplex assay.

Results:

One hundred and nine (47 HIV-exposed and 62 HIV-unexposed) mother–infants pairs were recruited after delivery and followed longitudinally. At birth, proportions of mycobacteria-specific proliferating T cells were not associated with either in-utero HIV exposure or maternal Mtb sensitization. However, in-utero HIV exposure affected infant-specific T-cell subsets [tumour necrosis factor-alpha (TNF-α) single positive proliferating CD4⁺ T cells and interferon-gamma (IFN-γ), TNF-α dual-positive CD4⁺ T cells]. Levels of TNF-α protein in cell culture supernatants were also significantly higher in HIV-exposed infants born to Mtb-sensitized mothers. In the presence of maternal Mtb sensitization, frequencies of maternal and newborn BCG-specific proliferating CD4⁺ T cells were positively correlated. Following BCG vaccination, there was no demonstrable effect of HIV exposure or maternal Mtb infection on infant BCG-specific T-cell proliferative responses or concentrations of secreted cytokines and chemokines.

Conclusion:

Effects of maternal HIV and Mtb infection on infant immune profiles at birth are transient only, and HIV-exposed, noninfected infants have the same potential to respond to and be protected by BCG vaccination as HIV-unexposed infants.

Control lymphocyte subsets: can one country's values serve for another's?

Lymphocyte subsets can be affected by host and environmental factors, yet direct comparisons of their patterns across continents are lacking. This work compares proportions and counts of lymphocyte subsets between healthy children from Thailand, Malawi and the USA. We analyzed subsets of 1,399 healthy children aged between 0 and 15 years: 281 Thai, 397 Malawian and 721American children. Existing data for five subsets were available for all three cohorts (Total T, CD4+ T, CD8+ T, natural killer (NK) and B cells), with data for another six subsets from the Thai and American cohorts (naïve, memory and activated CD4+ and CD8+ T cells). Cellular patterns between cohorts differed mainly in children under two years. Compared to American children, Thai children had higher median numbers of total T cells, CD8+ T cells and NK cells while Malawian children under 18 months, on average, had more CD8+ T cells and B cells. Both Thai and Malawian children had lower median CD4+ T cell percentages and CD4/CD8 ratios than American children. Thai children had more memory and activated CD8+ T cells than American children. Approximately one-fifth of Thai and Malawian HIV-uninfected healthy children aged 0-3 years met WHO-defined CD4+ count criteria for immune-deficiency in HIV-infected children. Healthy children from Thailand, Malawi and the USA have differences in lymphocyte subsets that are likely to be due to differences in ethnicity, exposure to infectious diseases and environmental factors. These results indicate the need for country-specific reference ranges for diagnosis and management of immunologic disorders.

Impact of HIV exposure on health outcomes in HIV-negative infants born to HIV-positive mothers in Sub-Saharan Africa

BACKGROUND

Up to 30% of infants may be HIV-exposed noninfected (ENI) in countries with high HIV prevalence, but the impact of maternal HIV on the child's health remains unclear.

METHODS

One hundred fifty-eight HIV ENI and 160 unexposed (UE) Mozambican infants were evaluated at 1, 3, 9, and 12 months postdelivery. At each visit, a questionnaire was administered, and HIV DNA polymerase chain reaction and hematologic and CD4/CD8 determinations were measured. Linear mixed models were used to evaluate differences in hematologic parameters and T-cell counts between the study groups. All outpatient visits and admissions were registered. ENI infants received cotrimoxazol prophylaxis (CTXP). Negative binomial regression models were estimated to compare incidence rates of outpatient visits and admissions.

RESULTS

Hematocrit was lower in ENI than in UE infants at 1, 3, and 9 months of age (P = 0.024, 0.025, and 0.012, respectively). Percentage of CD4 T cells was 3% lower (95% confidence interval: 0.86 to 5.15; P = 0.006) and percentage of CD8 T cells 1.15 times higher (95% confidence interval: 1.06 to 1.25; P = 0.001) in ENI vs. UE infants. ENI infants had a lower weight-for-age Z score (P = 0.049) but reduced incidence of outpatient visits, overall (P = 0.042), diarrhea (P = 0.001), and respiratory conditions (P = 0.042).

CONCLUSIONS

ENI children were more frequently anemic, had poorer nutritional status, and alterations in some immunologic profiles compared with UE children. CTXP may explain their reduced mild morbidity. These findings may reinforce continuation of CTXP and the need to understand the consequences of maternal HIV exposure in this vulnerable group of children.

Immunology of pediatric HIV infection

Most infants born to human immunodeficiency virus (HIV)-infected women escape HIV infection. Infants evade infection despite an immature immune system and, in the case of breastfeeding, prolonged repetitive exposure. If infants become infected, the course of their infection and response to treatment differs dramatically depending upon the timing (in utero, intrapartum, or during breastfeeding) and potentially the route of their infection. Perinatally acquired HIV infection occurs during a critical window of immune development. HIV's perturbation of this dynamic process may account for the striking age-dependent differences in HIV disease progression. HIV infection also profoundly disrupts the maternal immune system upon which infants rely for protection and immune instruction. Therefore, it is not surprising that infants who escape HIV infection still suffer adverse effects. In this review, we highlight the unique aspects of pediatric HIV transmission and pathogenesis with a focus on mechanisms by which HIV infection during immune ontogeny may allow discovery of key elements for protection and control from HIV.

Establishing the reference range for T lymphocytes subpopulations in adults and children from Brazil

SUMMARY

In Brazil, the existing reference values for T-lymphocytes subsets are based on data originated in other countries. There is no local information on normal variation for these parameters in Brazilian adults and children. We evaluated the normal variation found in blood donors from five large Brazilian cities, in different regions, and in children living in Salvador, and Rio de Janeiro. All samples were processed by flow cytometry. The results were analyzed according to region, gender, and lifestyle of blood donors. A total of 641 adults (63% males), and 280 children (58% males) were involved in the study. The absolute CD3+, and CD4+ cells count were significantly higher for females (adults and children). Higher CD4+ cell count in adults was associated with smoking, while higher CD8+ count was found among female children. Higher counts, for all T-cells subsets, were detected in blood donors from southeast / south regions while those living in the northern region had the lowest values. Individuals from midwestern and northeastern regions had an intermediate count for all these cells subsets. However, these differences did not reach statistical significance. In Brazil, gender and smoking, were the main determinants of differences in T-lymphocytes reference values.

Population specific reference ranges of CD3, CD4 and CD8 lymphocyte subsets among healthy Kenyans

Background

The enumeration of absolute CD4 counts is of primary importance for many medical conditions especially HIV infection where therapeutic initiation depends on the count. These ranges tend to vary across populations. However, these ranges have not been comprehensively established in the Kenyan population. Therefore, this study aimed at establishing the reference ranges for the CD4 and CD8 T-lymphocytes in normal healthy individuals in Kenya.

Methods

A total of 315 individuals of the ages between 16 and 60 years old, in 5 different regions of the country, were recruited into the study. They were screened for diseases that potentially cause lymphocyte homeostasis perturbation. CD4/CD8 Counts were performed by use of a FACSCalibur flow cytometer (Becton-Dickinson, NJ) equipped with automated acquisition and analysis software. Results were analysed according to age, sex and region.

Results

Results were presented as means and ranges (in parenthesis) generated non parametrically as 2.5 and 97.5 percentiles as follows; In general population; CD3 1655 (614-2685 cells/μL ), CD4 920 (343-1493 cells/μL), and CD8 646 (187-1139 cells/μL), while according to sex, females; CD3 1787 (697-2841 cells/μL), CD4 1010 (422-1572 cells/μL), CD8 659 (187-1180 cells/μL); males; CD3 1610 (581-2641 cells/μL), CD4 889(320-1459 cells/μL) and CD8 644 (185-1140 cells/μL). The general reference ranges for CD4/CD8 ratios were as follows; general population 1.57(0.50-2.74), males 1.51(0.49-2.64) and females 1.69(0.55-2.95).

Conclusion

The lymphocyte reference ranges for the Kenyan population are fairly comparable to those established in other African populations. The ranges also differ appreciably from those established in Germany, Italy and Switzerland. Furthermore, the study reported significant differences in the ranges of different population clusters within Kenya, as well us between males and females.

Performance evaluation of the MBio Diagnostics point-of-care CD4 counter

The measurement of the absolute CD4 T-cell count is critical in the initial evaluation and staging of HIV-infected persons, yet access to this technology remains limited in many low resource settings where disease burden is highest. Here we evaluate the performance of a prototype point-of-care device (POC) to quantify CD4 T cells from MBio Diagnostics, Inc. Whole blood samples, both venous and capillary (finger stick), were collected from known HIV-infected participants at the University of California, San Diego Antiviral Research Center, and tested using the MBio system and conventional flow cytometry. A total of 94 venipuncture and 52 capillary samples were processed and statistical analyses included comparison to flow cytometry results. For the venipuncture samples, Bland-Altman analysis resulted in a mean bias of -10 cells/μL (-23 to +3 cells/μL, 95% CI), and limits of agreement (LOA) of -132 and +112 cells/μL. For the capillary samples, Bland-Altman resulted in a mean bias of -4 cells/μL (-31 to +23 cells/μL, 95% CL), and LOA of -195 and +186 cells/μL. For the San Diego study cohort, the prototype MBio system showed negligible quantitative bias relative to flow cytometry. Higher variability was observed in the capillary samples relative to venipuncture, but system precision for both capillary and venipuncture samples was good. There was also close agreement between results from the same participant when tested with two different systems, different operators and different locations. This preliminary evaluation suggests that the MBio CD4 device holds promise as a POC system for quantitation of CD4 T cells in limited-resource settings.

Uninfected but not unaffected: chronic maternal infections during pregnancy, fetal immunity, and susceptibility to postnatal infections

Chronic infections during pregnancy are highly prevalent in some parts of the world. Infections with helminths, Trypanosoma cruzi, Plasmodium spp, and HIV might affect the development of fetal immunity and susceptibility to postnatal infections independently of in-utero transmission of the pathogens. Fetal adaptive immune responses are common in neonates who have been exposed to maternal infection during pregnancy but not infected themselves. Such responses could affect the development of immunity to the homologous pathogens and their control during the first few years of life. Fetal innate and regulatory responses might also affect immunity to unrelated pathogens and responses to vaccines. Strategies to improve child health should integrate the possible clinical implications of in-utero exposure to chronic maternal infections.

Hematologic and immunologic parameters in Zimbabwean infants: a case for using local reference intervals to monitor toxicities in clinical trials

Studies investigating novel therapies in African infants report laboratory adverse events based on reference intervals from white Western infants. However, prior studies have shown that reference intervals differ based on ethnicity and geographic location. We calculated reference intervals for Zimbabwean infants by analyzing the hematologic and immunologic values found in 542 blood samples from 269 HIV-uninfected, black, Zimbabwean infants at 3, 5 and 9 months of age. Substantial proportions of the platelet counts (44%), hemoglobins (19%) and mean corpuscular volumes (41%) were outside published normal ranges. The majority (65%) of hemoglobin values qualified as a United States National Institutes of Health Division of AIDS adverse events. The majority (71%) of CD4% values indicated immunodeficiency by World Health Organization criteria. Hematologic and immunologic reference intervals used to evaluate toxicities in pediatric trials in sub-Saharan Africa need to be reevaluated to account for differences in ethnicity, geographic location, nutrition and socioeconomic status.

Presumptive diagnosis of severe HIV infection to determine the need for antiretroviral therapy in children less than 18 months of age

OBJECTIVE

To develop a new algorithm for the presumptive diagnosis of severe disease associated with human immunodeficiency virus (HIV) infection in children less than 18 months of age for the purpose of identifying children who require antiretroviral therapy (ART).

METHODS

A conditional probability model was constructed and non-virologic parameters in various combinations were tested in a hypothetical cohort of 1000 children aged 6 weeks, 6 months and 12 months to assess the sensitivity, specificity, and positive and negative predictive values of these algorithms for identifying children in need of ART. The modelled parameters consisted of clinical criteria, rapid HIV antibody testing and CD4+ T-lymphocyte (CD4) count.

FINDINGS

In children younger than 18 months, the best-performing screening algorithm, consisting of clinical symptoms plus antibody testing plus CD4 count, showed a sensitivity ranging from 71% to 80% and a specificity ranging from 92% to 99%. Positive and negative predictive values were between 61% and 97% and between 95% and 96%, respectively. In the absence of virologic tests, this alternate algorithm for the presumptive diagnosis of severe HIV disease makes it possible to correctly initiate ART in 91% to 98% of HIV-positive children who are at highest risk of dying.

CONCLUSION

The algorithms presented in this paper have better sensitivity and specificity than clinical parameters, with or without rapid HIV testing, for the presumptive diagnosis of severe disease in HIV-positive children less than 18 months of age. If implemented, they can increase the number of HIV-positive children successfully initiated on ART.

Reference values of lymphocyte subsets in healthy, HIV-negative children in Cameroon

Lymphocyte subset reference values used to monitor infectious diseases, including HIV/AIDS, tuberculosis, malaria, or other immunological disorders in healthy children in Cameroon, are lacking. Values for Caucasian cohorts are already being utilized for clinical decisions but could be inappropriate for African populations. We report here the immunological profile for children aged from birth through 6 years in Cameroon and also compare our values to data from other African and Caucasian populations. In a cohort of 352 healthy children, aged 0 to 6 years, the relative and absolute numbers of T-cell subsets, B cells, and NK lymphocytes were determined from peripheral blood collected in EDTA tubes. Samples were stained with BD Multitest reagents in Trucount tubes and analyzed by using CellQuest-Pro and FlowJo software. We evaluated about 23 different lymphocyte subsets in which the absolute number and percentage values differed significantly (P < 0.05) with age and peaked between 6 and 12 months. B-cell values were higher compared to reported values from developed countries. Differences in activated and differentiated T cells were observed in subjects between 1 and 6 years of age. The absolute CD8(+) T-cell count and the CD4(+)/CD8(+) ratio seem to depend on gender. Normal lymphocyte subsets values among children from Cameroon differ from reported values in Caucasian and some African populations. The differences observed could be due to genetic and environmental factors coupled with the methodology used. These values could be used as initial national reference guidelines as more data are assembled.

Establishment of haematological and immunological reference values for healthy Tanzanian children in Kilimanjaro Region

OBJECTIVE

To determine the normal haematological and immunological reference intervals for healthy Tanzanian children.

METHODS

We analysed data from 655 HIV-seronegative, healthy children from 1 month to 18 years of age from the Kilimanjaro Region of Tanzania for this cross-sectional study. Median and 95% reference ranges were determined for haematological and immunological parameters and analysed by age cohorts, and by gender for adolescents.

RESULTS

Median haemoglobin (Hb) and haematocrit (Hct) for all age groups were higher than established East African reference intervals. Compared to U.S. intervals, reference ranges encompassed lower values for Hb, Hct, mean corpuscular volume, and platelets. Applying the U.S. National Institute of Health Division of AIDS (DAIDS) adverse event grading criteria commonly used in clinical trials to the reference range participants, 128 (21%) of 619 children would be classified as having an adverse event related to Hb level. CD4-positive T-lymphocyte absolute counts declined significantly with increasing age (P < 0.0001). For those aged under five years, CD4-positive T-lymphocyte percentages are lower than established developed country medians.

CONCLUSIONS

Country-specific reference ranges are needed for defining normal laboratory parameters among children in Africa. Knowledge of appropriate reference intervals is critical not only for providing optimal clinical care, but also for enrolling children in medical research. Knowledge of normal CD4-positive T-lymphocyte parameters in this population is especially important for guiding the practice of HIV medicine in Tanzania.

Clinical presentation and outcome of epidemic Kaposi sarcoma in Ugandan children

BACKGROUND

Kaposi sarcoma (KS) is one of the most common pediatric cancers in sub-Saharan Africa. Few data are available about the clinical presentation or response to treatment of children with epidemic (HIV-associated) KS.

METHODS

Medical records of all children with KS and HIV infection referred to the Uganda Cancer Institute in Kampala, Uganda from October 2004 to June 2007 were reviewed. Charts were abstracted for age, sex, location of KS lesions at presentation, biopsy results, CD4 T-cell count and percentage, and KS treatment and outcome.

RESULTS

Seventy-three children with epidemic KS were identified, 37 males and 36 females. The median age was 10.1 years (range 2-18). KS presented with lymph node (LN) involvement in 60% of cases. The median absolute and percentage CD4 T-cells at presentation were 210 cells/microl and 7.4%, respectively. Those children with lymphadenopathic KS were younger (mean difference 3.7 years; P = 0.01) and had higher CD4 T-cell counts (mean difference 242 cells/microl; P = 0.03) than those without LN involvement. Of 32 patients for whom outcome data were available, a complete response to chemotherapy and/or antiretroviral therapy was documented in 20 (62.5%) patients.

CONCLUSIONS

In comparison to cutaneous involvement, LN involvement of epidemic KS occurs at younger ages and at higher CD4 levels. This clinical presentation may reflect recent infection with human herpesvirus 8 followed by a rapid progression to malignancy. Favorable response to treatment was observed in the majority of cases, but prospective studies are needed to determine optimal management.

T-lymphocyte subsets in apparently healthy nigerian children

Population studies showed that there are differences in T-lymphocytes subpopulation of normal children in different regions, and reference values in an area might be different from another. This study compared the values in our population with CDC and WHO reference values. Blood samples from 279 healthy, HIV-negative children <12 years of age were analysed for complete blood count, CD3+, CD4+, CD8+ counts and percentages. Except for CD8%, mean values for all parameters measured significantly decreased with age. CD4+ counts were higher in females than males, P < .05. Using the WHO criteria, 15.9% of subjects had low total lymphocyte count and 20.6% had low CD4 count. Children <3 years had median CD4% lower than WHO normal values. Our median CD4+ counts correlated with CDC values. Values used by WHO in infants are higher than ours. We suggest that our children be assessed using CDC reference values which correlate with ours.

Effectiveness of pediatric antiretroviral therapy in resource-limited settings: a systematic review and meta-analysis

BACKGROUND

Responses to antiretroviral therapy (ART) among human immunodeficiency virus (HIV)-infected children in resource-limited settings have recently been reported, but outcomes vary. We sought to derive pooled estimates of the 12-month rate of virologic suppression (HIV RNA, <400 copies/mL) and gain in CD4 cell percentage (DeltaCD4%) for children initiating ART in resource-limited settings.

METHODS

We conducted a systematic review and meta-analysis of published reports of HIV RNA and CD4 outcomes for treatment-naive children aged 0-17 years old by means of the Medline, EMBASE (Excerpta Medica Database), and LILACS (Latin American and Caribbean Health Sciences Literature) electronic databases and the Cochrane Clinical Trials Register. Pooled estimates of the reported proportion with HIV RNA <400 copies/mL and DeltaCD4% after 12 months of ART were derived using patient-level estimates and fixed- and random-effects models. To approximate intention-to-treat analyses, in sensitivity analyses children with missing 12-month data were assumed to have HIV RNA>400 copies/mL or DeltaCD4% of zero.

RESULTS

In patient-level estimates after 12 months of ART, the pooled proportion with virologic suppression was 70% (95% confidence interval [CI], 67%-73%); the pooled DeltaCD4% was 13.7% (95% CI, 11.8%-15.7%). Results from the fixed- and random-effects models were similar. In approximated intention-to-treat analyses, the pooled estimates decreased to 53% with virologic suppression (95% CI, 50%-55%) and to a DeltaCD4% of 8.5% (95% CI, 5.5%-11.4%).

CONCLUSIONS

Pooled estimates of reported virologic and immunologic benefits after 12 months of ART among HIV-infected children in resource-limited settings are comparable with those observed among children in developed settings. Consistency in reporting on reasons for missing data will aid in the evaluation of ART outcomes in resource-limited settings.

Human immunodeficiency virus (HIV) infection during pregnancy induces CD4 T-cell differentiation and modulates responses to Bacille Calmette-Guérin (BCG) vaccine in HIV-uninfected infants

Human immunodeficiency virus (HIV)-negative infants born to HIV-positive mothers frequently exhibit a range of immunological abnormalities. We tested the hypothesis that HIV during pregnancy affects the ability of CD4 T cells of HIV-negative infants to respond to vaccine challenge by recruiting HIV-negative infants born to HIV-negative and HIV-positive mothers and measuring their responses to Bacille Calmette-Guérin (BCG) vaccine given at birth. At 2 weeks, maternal HIV status did not influence CD4 T-cell counts or differentiation, but by 10 weeks CD4 counts of infants born to HIV-positive mothers fell to a level characteristic of HIV-positive infants. Among the CD4 T-cell populations, markers of differentiation (CCR7⁻ CD45RA⁻ CD27⁻) and senescence (CD57, PD-1) were more common among infants born to HIV-positive mothers than among infants born to HIV-negative mothers. At 2 weeks of age, we assessed the effector response to heat-killed BCG and tuberculin purified protein derivative (PPD) by overnight interferon (IFN)-γ enzyme-linked immunosorbent spot-forming cell assay (ELISpot), but found no measurable effect of maternal HIV status. At 10 weeks, we assessed CD4 T-cell memory by measuring proliferation in response to the same antigens. We observed a bimodal response that allowed infants to be classified as high or low responders and found that fewer infants born to HIV-positive mothers were able to mount a robust proliferative response, suggesting that their reduced CD4 counts and increased differentiation indicated a deficiency in their ability to develop immunological memory.

Lymphocyte subsets in healthy Malawians: implications for immunologic assessment of HIV infection in Africa

Background

CD4⁺T lymphocyte measurements are the most important indicator of mortality in HIV-infected individuals in resource-limited settings. There is currently a lack of comprehensive immunophenotyping data from African populations to guide the immunologic assessment of HIV infection.

Objective

To quantify variation in absolute and relative lymphocyte subsets with age in healthy Malawians.

Methods

Lymphocyte subsets in peripheral blood of 539 healthy HIV-uninfected Malawians stratified by age were enumerated by flow cytometry.

Results

B and T–lymphocyte and T-lymphocyte subset absolute concentrations peaked in early childhood then decreased to adult levels, whereas lymphocyte subset proportions demonstrated much less variation with age. Adult lymphocyte subsets were similar to those in developed countries. In contrast, high B-lymphocyte and CD8⁺T-lymphocyte levels among children under 2 years, relative to those in developed countries, resulted in low CD4⁺T-lymphocyte percentages that varied little between 0 and 5 years (35% to 39%). The CD4⁺T-lymphocyte percentages in 35% of healthy children under 1 year and 18% of children age 1 to 3 years were below the World Health Organization threshold defining immunodeficiency in HIV-infected children in resource-limited settings. Thirteen percent of healthy children under 18 months old had a CD4:CD8T-lymphocyte ratio <1.0, which is commonly associated with HIV infection. All immunologic parameters except absolute natural killer lymphocyte concentration varied significantly with age, and percentage and overall absolute CD4⁺T-lymphocyte counts were higher in females than males.

Conclusion

Although lymphocyte subsets in Malawian adults are similar to those from developed countries, CD4⁺T-lymphocyte percentages in young children are comparatively low. These findings need to be considered when assessing the severity of HIV-related immunodeficiency in African children under 3 years.

Patterns and predictors of CD4 T-cell counts among children born to HIV-infected women in Tanzania

We assessed age-specific CD4 T-cell counts and their determinants among Tanzanian children born to HIV-infected mothers to address a major research gap. A total of 474 HIV-uninfected and 69 HIV-infected children were followed until age of 12 months. Maternal predictors were measured during pregnancy and child predictors at birth and throughout the follow up. Child CD4 T-cell counts were evaluated at the age of 3 months and subsequent 3-month intervals; they decreased linearly among HIV-infected (beta = -8 cells per week; 95% CI -12 to -4; P = 0.0003) and increased linearly among HIV-uninfected children (beta = 4 cells/week; 95% CI 2-7; P = 0.0008). Decreased child counts were predicted by low child anthropometry, maternal HIV stage > or =2, and maternal mid-upper arm circumference <27 cm among HIV-infected children; and by weight-for-height <-2 z-score, maternal HIV stage > or =2, maternal erythrocyte sedimentation rate <81 mm/h and maternal haemoglobin <8.5 g/dl among HIV-uninfected children. The maternal and child predictors described may serve as intervention targets among HIV-exposed children.

Selected hematologic and biochemical measurements in African HIV-infected and uninfected pregnant women and their infants: the HIV Prevention Trials Network 024 protocol

Background

Reference values for hematological and biochemical assays in pregnant women and in newborn infants are based primarily on Caucasian populations. Normative data are limited for populations in sub-Saharan Africa, especially comparing women with and without HIV infection, and comparing infants with and without HIV infection or HIV exposure.

Methods

We determined HIV status and selected hematological and biochemical measurements in women at 20–24 weeks and at 36 weeks gestation, and in infants at birth and 4–6 weeks of age. All were recruited within a randomized clinical trial of antibiotics to prevent chorioamnionitis-associated mother-to-child transmission of HIV (HPTN024). We report nearly complete laboratory data on 2,292 HIV-infected and 367 HIV-uninfected pregnant African women who were representative of the public clinics from which the women were recruited. Nearly all the HIV-infected mothers received nevirapine prophylaxis at the time of labor, as did their infants after birth (always within 72 hours of birth, but typically within just a few hours at the four study sites in Malawi (2 sites), Tanzania, and Zambia.

Results

HIV-infected pregnant women had lower red blood cell counts, hemoglobin, hematocrit, and white blood cell counts than HIV-uninfected women. Platelet and monocyte counts were higher among HIV-infected women at both time points. At the 4–6-week visit, HIV-infected infants had lower hemoglobin, hematocrit and white blood cell counts than uninfected infants. Platelet counts were lower in HIV-infected infants than HIV-uninfected infants, both at birth and at 4–6 weeks of age. At 4–6 weeks, HIV-infected infants had higher alanine aminotransferase measures than uninfected infants.

Conclusion

Normative data in pregnant African women and their newborn infants are needed to guide the large-scale HIV care and treatment programs being scaled up throughout the continent. These laboratory measures will help interpret clinical data and assist in patient monitoring in a sub-Saharan Africa context.

Trial Registration

nicalTrials.gov Identifier NCT00021671.

Performance of clinical algorithms for HIV-1 diagnosis and antiretroviral initiation among HIV-1-exposed children aged less than 18 months in Kenya

BACKGROUND

Ninety percent of HIV-1-infected children live in sub-Saharan Africa. In the absence of diagnosis and antiretroviral therapy, approximately 50% die before 2 years.

METHODS

We evaluated sensitivity and specificity of clinical algorithms for diagnosis of HIV-1 infection and antiretroviral therapy initiation among HIV-1-exposed children aged less than 18 months. Children were identified with routine HIV-1 testing and assessed using 3 sets of criteria: (1) Integrated Management of Childhood Illnesses (IMCI), (2) World Health Organization Presumptive Diagnosis (WHO-PD) for HIV-1 infection, and (3) CD4 T-lymphocyte cell subsets. HIV-1 infection status was determined using DNA polymerase chain reaction testing.

FINDINGS

A total of 1418 children (median age 5.4 months) were screened for HIV-1 antibodies, of whom 144 (10.2%) were seropositive. Of these, 134 (93%) underwent HIV-1 DNA testing and 80 (60%) were found to be HIV-1 infected. Compared with HIV-1 DNA testing, sensitivity and specificity of the IMCI criteria were 19% and 96% and for WHO-PD criteria 43% and 88%, respectively. Inclusion of severe immune deficiency determined by CD4% improved sensitivity of IMCI and WHO-PD criteria to 74% and 84%, respectively; however, specificity declined to 43% and 41%, respectively.

INTERPRETATION

Diagnosis of HIV-1 infection among exposed children less than 18 months in a high-prevalence resource-limited setting remains a challenge, and current recommended algorithms have low sensitivity. This underscores the need for rapid scale-up of viral assays for early infant diagnosis.

The HIV-exposed, uninfected African child

The increasing success of prevention of mother-to-child HIV transmission programmes means that in Africa, very large numbers of HIV-exposed, uninfected (HIV-EU) children are being born. Any health problems that these children may have will thus be of enormous public health importance, but to date have been largely neglected. There is some evidence that HIV-EU African children are at increased risk of mortality, morbidity and slower early growth than their HIV-unexposed counterparts. A likely major cause of this impaired health is less exposure to breast milk as mothers are either less able to breastfeed or stop breastfeeding early to protect their infant from HIV infection. Other contributing factors are parental illness or death resulting in reduced care of the children, increased exposure to other infections and possibly exposure to antiretroviral drugs. A broad approach for psychosocial support of HIV-affected families is needed to improve health of HIV-EU children. High quality programmatic research is needed to determine how to deliver such care.

Human immunodeficiency virus (HIV) type 1 proviral hypermutation correlates with CD4 count in HIV-infected women from Kenya

APOBEC3G is an important innate immune molecule that causes human immunodeficiency virus type 1 (HIV-1) hypermutation, which can result in detrimental viral genome mutations. The Vif protein of wild-type HIV-1 counteracts APOBEC3G activity by targeting it for degradation and inhibiting its incorporation into viral particles. Additional APOBEC cytidine deaminases have been identified, such as APOBEC3F, which has a similar mode of action but different sequence specificity. A relationship between APOBEC3F/G and HIV disease progression has been proposed. During HIV-1 sequence analysis of the vpu/env region of 240 HIV-infected subjects from Nairobi, Kenya, 13 drastically hypermutated proviral sequences were identified. Sequences derived from plasma virus, however, lacked hypermutation, as did proviral vif. When correlates of disease progression were examined, subjects with hypermutated provirus were found to have significantly higher CD4 counts than the other subjects. Furthermore, hypermutation as estimated by elevated adenine content positively correlated with CD4 count for all 240 study subjects. The sequence context of the observed hypermutation was statistically associated with APOBEC3F/G activity. In contrast to previous studies, this study demonstrates that higher CD4 counts correlate with increased hypermutation in the absence of obvious mutations in the APOBEC inhibiting Vif protein. This strongly suggests that host factors, such as APOBEC3F/G, are playing a protective role in these patients, modulating viral hypermutation and host disease progression. These findings support the potential of targeting APOBEC3F/G for therapeutic purposes.

Computed CD4 percentage as a low-cost method for determining pediatric antiretroviral treatment eligibility

Background

The performance of the WHO recommendations for pediatric antiretroviral treatment (ART) in resource poor settings is insufficiently documented in routine care.

Methods

We compared clinical and immunological criteria in 366 children aged 0 to 12 years in Kinshasa and evaluated a simple computation to estimate CD4 percent, based on CD4 count, total white blood cell count and percentage lymphocytes. Kappa (κ) statistic was used to evaluate eligibility criteria and linear regression to determine trends of CD4 percent, count and total lymphocyte count (TLC).

Results

Agreement between clinical and immunological eligibility criteria was poor (κ = 0.26). One third of children clinically eligible for ART were ineligible using immunological criteria; one third of children immunologically eligible were ineligible using clinical criteria. Among children presenting in WHO stage I or II, 54 (32%) were eligible according to immunological criteria. Agreement with CD4 percent was poor for TLC (κ = 0.04), fair for total CD4 count (κ = 0.39) and substantial for CD4 percent computational estimate (κ = 0.71). Among 5 to 12 years old children, total CD4 count was higher in younger age groups (-32 cells/mm³ per year older), CD4 percent was similar across age groups.

Conclusion

Age-specific thresholds for CD4 percent optimally determine pediatric ART eligibility. The use of CD4 percent computational estimate may increase ART access in settings with limited access to CD4 percent assays.

Markers for predicting mortality in untreated HIV-infected children in resource-limited settings: a meta-analysis

OBJECTIVES

To evaluate the prognostic value of selected laboratory and growth markers on the short-term risk of mortality in untreated HIV-infected children in resource-limited settings.

DESIGN

A meta-analysis of individual longitudinal data on children aged 12 months onwards from 10 studies (nine African, one Brazilian in the 3Cs4kids collaboration).

METHODS

The risk of death within 12 months based on age and the most recent measurements of laboratory and growth markers was estimated using Poisson regression models, adjusted for cotrimoxazole prophylaxis use and study effects.

RESULTS

A total of 2510 children contributed 357 deaths during 3769 child-years-at-risk, with 81% follow-up occurring after start of cotrimoxazole. At first measurement, median age was 4.0 years (interquartile range, 2.2-7.0 years), median CD4% was 15% and weight-for-age z-score -1.9. CD4% and CD4 cell count were the strongest predictors of mortality, followed by weight-for-age and haemoglobin. After adjusting for these markers, the effects of total lymphocyte count and BMI-for-age were relatively small. Young children who were both severely malnourished and anaemic had high mortality regardless of CD4 values, particularly those aged 1-2 years. By contrast, high CD4% or CD4 cell count values predicted low mortality level amongst either children older than 5 years or those younger with neither severe malnutrition nor anaemia.

CONCLUSIONS

CD4 measurements are the most important indicator of mortality and wider access to affordable tests is needed in resource-limited settings. Evaluation of antiretroviral initiation in children also needs to consider weight-for-age and haemoglobin. Prevention and treatment of malnutrition and anaemia is integral to HIV paediatric care and could improve survival.

Severe malnutrition with and without HIV-1 infection in hospitalised children in Kampala, Uganda: differences in clinical features, haematological findings and CD4+ cell counts

BACKGROUND

The aim of this study was to describe the clinical features, haematological findings and CD4+ and CD8+ cell counts of severely malnourished children in relation to human immunodeficiency virus (HIV) infection.

METHODS

The study was conducted in the paediatric wards of Mulago hospital, which is Uganda's national referral and teaching hospital. We studied 315 severely malnourished children (presence of oedema and/or weight-for-height: z-score < -3) and have presented our findings. At admission, the CD4+ and CD8+ cells were measured by the flow cytometry and HIV serology was confirmed by Enzyme linked Immunoassay for children >18 months of age, and RNA PCR was performed for those < or =18 months. Complete blood count, including differential counts, was determined using a Beckman Coulter counter.

RESULTS

Among the 315 children, 119 (38%) were female; the median age of these children was 17 months (Interquartile range 12-24 months), and no difference was observed in the HIV status with regard to gender or age. The children showed a high prevalence of infections: pneumonia (68%), diarrhoea (38%), urinary tract infection (26%) and bacteraemia (18%), with no significant difference with regard to the HIV status (HIV-positive versus HIV-negative children). However, the HIV-positive children were more likely to have persistent diarrhoea than the HIV-uninfected severely malnourished children (odds ratio (OR) 2.0, 95% confidence interval (CI) 1.2-3.6). When compared with the HIV-negative children, the HIV-positive children showed a significantly lower median white blood cell count (10700 versus 8700) and lymphocyte count (4033 versus 2687). The CD4+ cell percentages were more likely to be lower in children with non-oedematous malnutrition than in those with oedematous malnutrition even after controlling for the HIV infection. The novel observation of this study is that the CD4+ percentages in both HIV-positive and HIV-negative children without oedema were lower that those in children with oedema. These observations appear to imply that the development of oedema requires a certain degree of immunocompetence, which is an interesting clue to the pathophysiology of oedema in severe malnutrition.

T lymphocytes among HIV-infected and -uninfected infants: CD4/CD8 ratio as a potential tool in diagnosis of infection in infants under the age of 2 years

BACKGROUND: Serologic tests for HIV infection in infants less than 18 months do not differentiate exposure and infection since maternally acquired IgG antibodies may be detected in infants. Thus, the gold standard for diagnosis of HIV-1 infection in infants under the age of 2 years is DNA or reverse transcriptase polymerase chain reaction. There is an urgent need to evaluate alternative and cost effective laboratory methods for early diagnosis of infant HIV-1 infection as well as identifying infected infants who may benefit from cotrimoxazole prophylaxis and/or initiation of highly active antiretroviral therapy. METHODS: Whole blood was collected in EDTA from 137 infants aged 0 to 18 months. DNA polymerase chain reaction was used as the reference standard for diagnosis of HIV-1 infection. T-cell subset profiles were determined by flow cytometry. RESULTS: Seventy-six infants were DNA PCR positive while 61 were negative. The median CD4 counts of PCR negative infants were significantly higher than those of the PCR positive infants, p < 0.001. The median CD4/CD8 ratio and the %CD4 of the PCR positive infants were both significantly lower than those of the negative infants, p < 0.001. The CD4/CD8 ratio had a >98% sensitivity for diagnosis of HIV-1 infection and a specificity of >98%. CONCLUSION: The CD4/CD8 ratio appears useful in identifying HIV-infected infants. The development of lower cost and more robust flow cytometric methods that provide both CD4/CD8 ratio and %CD4 may be cost-effective for HIV-1 diagnosis and identification of infants for cotrimoxazole prophylaxis and/or highly active antiretroviral therapy.

Population-based hematologic and immunologic reference values for a healthy Ugandan population

To assess the validity of the reference values for hematologic and immunologic indices currently used in Africa, we evaluated blood samples from 3,311 human immunodeficiency virus (HIV)-negative Ugandans aged 1 week to 92 years. Erythrocyte, hemoglobin, and hematocrit levels and mean corpuscular volume all significantly increased with age (P < 0.001) and were independent of gender until the age of 13 years, after which the levels were higher in males than in females (P < 0.001). White blood cell, neutrophil, lymphocyte, basophil, and monocyte counts significantly declined with age until the age of 13 years (P < 0.001), with no differences by gender, while platelet counts declined with age (P < 0.001) and showed differences by gender only among adults older than age 24 years. CD4+- and CD8+-cell counts declined with age until the age of 18 years; thereafter, females had higher counts than males. The absolute values for many of these parameters differed from those reported for populations outside Africa, suggesting that it may be necessary to develop tables of reference values for hematologic and immunologic indices specific for the African population. This may be particularly important with regard to CD4+-cell counts among children because significant differences in absolute and percent CD4+-cell counts exist between the values for Western populations and the values for the population evaluated in our study. These differences could influence the decision to initiate antiretroviral therapy among children infected with HIV.

Immunophenotyping of blood lymphocytes at birth, during childhood, and during adulthood in HIV-1-uninfected Ethiopians

To obtain more insight into blood lymphocyte subpopulations of Ethiopians, we studied the immunologic profile of children and neonates and compared these data with those obtained from adults. Peripheral blood mononuclear cells (PBMCs) and cord blood mononuclear cells (CBMCs) were collected from 137 HIV-1-uninfected subjects aged 0 (cord blood) up to 40 years. Lymphocyte subsets (T, B, and NK cells, CD4+ and CD8+ T cells) were determined and T cell activation (CD38 and HLA-DR) and differentiation (CD45RO and CD27) markers were measured on CD4+ and CD8+ T cells. The absolute number and percentage values of most lymphocyte subpopulations differed substantially with age. Neonates and children were found to have significantly higher CD4+ T cell counts compared to adults. The median absolute CD4 count at birth was comparable to those reported for Caucasians. At birth 97% of the CD4+ T cells were naîve and this proportion significantly declined to 14.2% during adulthood. In addition, activation of both CD4+ and CD8+ T cells, as determined by the double expression of HLA-DR and CD38, was observed in children under the age of 16 and adults, but not in neonates. A more differentiated phenotype (CD27-) was observed in adults compared to children for both CD4+ and CD8+ T cells. The immune alterations including the remarkably low CD4 count with highly depleted naîve phenotype and a persistently activated immune system seen in adult Ethiopians are not apparent at birth, but rather develop over time.

Are there gender and race differences in cellular immunity patterns over age in infected and uninfected children born to HIV-infected women?

This study investigated whether age-related patterns of immunologic markers in 1488 uninfected (9789 measurements) and 186 infected (3414 measurements) children differed by gender and race. CD4+, CD8+, and absolute lymphocytes by HIV infection status, gender, and race were assessed using linear mixed-effects natural cubic spline models, allowing for prematurity and maternal CD4+ cell count. In uninfected children, levels of all 3 markers peaked twice in the first few months of life, declining to adult levels by around 8 years of age; uninfected boys and uninfected black children had significantly reduced CD4+ and absolute lymphocyte counts; the gender difference was especially pronounced in black children. Infected children had substantially lower levels and distinctly different patterns; with, e.g., by age 6 months CD4+ cell counts nearly 1200 per mm3 lower than in uninfected infants. Levels also significantly differed by gender and race for infected children, although for gender in the opposite direction. The gender and race differences in CD4+ levels were not explained by a general lymphocytosis nor were they confounded by treatment. These substantial differences in immunologic markers may reflect underlying genetic influence on the cellular immune system and may have implications for clinical decisions about therapeutic management.

A simplified approach to determining P-glycoprotein expression in peripheral blood mononuclear cell subsets

P-glycoprotein (P-gp), encoded by the MDR-1 (multidrug resistance) gene mediates the cellular efflux of several therapeutic agents with the potential of treatment failure. The differential expression of P-gp in many localised tissues and cells of the hematopoietic system implies diverse physiological and pharmacological roles. The exact function of P-gp involved in multidrug resistance remains unclear owing to the numerous discrepancies between different laboratories. The ability to characterise accurately P-gp expression has important clinical implications. However, a complete consensus recommendation regarding methods of P-gp detection has been difficult to reach. With the advancement in immune technology and new commercially available antibodies, we describe a simplified direct immunofluorescent assay capable of detecting surface P-gp expression in peripheral blood mononuclear cells (PBMCs) and subpopulations of lymphocytes in vivo by dual colour flow cytometry. Results were expressed as mean increase in fluorescence (MI) compared to isotypically matched controls. Using this assay, differential basal P-gp expression was found to exist in the following significant hierarchy CD56+ (MI=0.684+/-0.273; n=15)>CD8+ (MI=0.312+/-0.117; n=15)>CD4+ (MI=0.194+/-0.086; n=15). This method is rapid and reproducible and has potential use for in vitro and in vivo application.