Low CD4+ T-lymphocyte values in human immunodeficiency virus-negative adults in Botswana

A Critical Review on the Standardization and Quality Assessment of Nonfunctional Laboratory Tests Frequently Used to Identify Inborn Errors of Immunity

Inborn errors of immunity (IEI), which were previously termed primary immunodeficiency diseases, represent a large and growing heterogeneous group of diseases that are mostly monogenic. In addition to increased susceptibility to infections, other clinical phenotypes have recently been associated with IEI, such as autoimmune disorders, severe allergies, autoinflammatory disorders, benign lymphoproliferative diseases, and malignant manifestations. The IUIS 2019 classification comprises 430 distinct defects that, although rare individually, represent a group affecting a significant number of patients, with an overall prevalence of 1:1,200-2,000 in the general population. Early IEI diagnosis is critical for appropriate therapy and genetic counseling, however, this process is deeply dependent on accurate laboratory tests. Despite the striking importance of laboratory data for clinical immunologists, several IEI-relevant immunoassays still lack standardization, including standardized protocols, reference materials, and external quality assessment programs. Moreover, well-established reference values mostly remain to be determined, especially for early ages, when the most severe conditions manifest and diagnosis is critical for patient survival. In this article, we intend to approach the issue of standardization and quality control of the nonfunctional diagnostic tests used for IEI, focusing on those frequently utilized in clinical practice. Herein, we will focus on discussing the issues of nonfunctional immunoassays (flow cytometry, enzyme-linked immunosorbent assays, and turbidimetry/nephelometry, among others), as defined by the pure quantification of proteins or cell subsets without cell activation or cell culture-based methods.

Assessment of the AQUIOS flow cytometer - An automated sample preparation system for CD4 lymphocyte PanLeucogating enumeration

Background

Flow cytometry has been the approach of choice for enumerating and documenting CD4-cell decline in HIV monitoring. Beckman Coulter has developed a single platform test for CD4+ T-cell lymphocyte count and percentage using PanLeucogating (PLG) technology on the automated AQUIOS flow cytometer (AQUIOS PLG).

Objectives

This study compared the performance of AQUIOS PLG with the Flowcare PLG method and performed a reference interval for comparison with those previously published.

Methods

The study was conducted between November 2014 and March 2015 at 5 different centres located in Canada; Paris, France; Lyon, France; the United States; and South Africa. Two-hundred and forty samples from HIV-positive adult and paediatric patients were used to compare the performances of AQUIOS PLG and Flowcare PLG on a FC500 flow cytometer (Flowcare PLG) in determining CD4+ absolute count and percentage. A reference interval was determined using 155 samples from healthy, non-HIV adults. Workflow was investigated testing 440 samples over 5 days.

Results

Mean absolute and relative count bias between AQUIOS PLG and Flowcare PLG was −41 cells/µL and −7.8%. Upward and downward misclassification at various CD4 thresholds was ≤ 2.4% and ≤ 11.1%. The 95% reference interval (2.5th – 97.5th) for the CD4+ count was 453–1534 cells/µL and the percentage was 30.5% – 63.4%. The workflow showed an average number of HIV samples tested as 17.5 per hour or 122.5 per 8-hour shift for one technician, including passing quality controls.

Conclusion

The AQUIOS PLG merges desirable aspects from conventional flow cytometer systems (high throughput, precision and accuracy, external quality assessment compatibility) with low technical operating skill requirements for automated, single platform systems.

[HIV infection and immigration]

Migrants represent around one third of patients newly diagnosed with HIV in Spain and they constitute a population with higher vulnerability to its negative consequences due to the socio-cultural, economical, working, administrative and legal contexts. Migrants are diagnosed later, which worsens their individual prognosis and facilitates the maintenance of the HIV epidemic. In spite of the different barriers they experience to access healthcare in general, and HIV-related services in particular, access to antiretroviral treatment has been similar to that of the autochthonous population. However, benefits of treatment have been not, with women in general and men from Sub-Saharan Africa exhibiting the worse response to treatment. We need to proactively promote earlier diagnosis of HIV infection, the adoption of preventive measures to avoid new infections, and to deliver accessible, adapted and high-quality health-care.

CD4 Cell Count: Declining Value for Antiretroviral Therapy Eligibility

Antiretroviral therapy (ART) policy for people living with human immunodeficiency virus (HIV) has historically been based on clinical indications, such as opportunistic infections and CD4 cell counts. Studies suggest that CD4 counts early in HIV infection do not predict relevant public health outcomes such as disease progression, mortality, and HIV transmission in people living with HIV. CD4 counts also vary widely within individuals and among populations, leading to imprecise measurements and arbitrary ART initiation. To capture the clinical and preventive benefits of treatment, the global HIV response now focuses on increasing HIV diagnosis and ART coverage. CD4 counts for ART initiation were necessary when medications were expensive and had severe side effects, and when the impact of early ART initiation was unclear. However, current evidence suggests that although CD4 counts may still play a role in guiding clinical care to start prophylaxis for opportunistic infections, CD4 counts should cease to be required for ART initiation.

Establishment of Normal Reference Intervals for CD3(+), CD4(+), CD8(+), and CD4(+) to CD8(+) Ratio of T Lymphocytes in HIV Negative Adults from University of Gondar Hospital, North West Ethiopia

Background. Reference values for the CD3⁺, CD4⁺, CD8⁺, and CD4⁺ to CD8⁺ ratio T lymphocyte subsets are adopted from textbooks. But for appropriate diagnosis, treatment, and follow-up of patients, correct interpretations of the laboratory results from normal reference interval are mandatory. This study was, therefore, planned to establish normal reference interval for T lymphocytes subset count and CD4⁺ to CD8⁺ ratio. Methods. A cross-sectional study was conducted on apparently healthy adult individuals who visited voluntary counseling and HIV testing clinic Gondar University Hospital from April to May, 2013. Whole blood was analyzed using fluorescence-activated cell sorting (BD FACS, San Jose, CA) machine to enumerate the T-cell subpopulations. Results. Out of the total 320 study participants, 161 (50.3%) were men and 159 (49.7%) were women. The normal reference intervals were (655–2,823 cells/μL), (321–1,389 cells/μL), and (220–1,664 cells/μL) for CD3⁺, CD4⁺, and CD8⁺ T lymphocyte subsets, respectively, and CD4⁺ to CD8⁺ ratio was 0.5–2.5. Conclusion. The overall CD3⁺ T lymphocytes reference interval in the current study was wide; low CD4⁺ T lymphocytes, CD4 to CD8 ratio, and high CD8⁺ T lymphocytes values were observed.

Normal CD4 Count Range among Healthy Nigerian Population in Ilorin

BACKGROUND

For the establishment and monitoring of the immune status, CD4 count is critical.

OBJECTIVES

To determine the CD4 count range of apparently healthy Nigerians resident in Ilorin and compare with the national value.

METHODS

An automated blood analyzer was used to determine the full blood count and CD4 count. The percentage of CD4 count was derived by using other variables.

RESULTS

Of the 1205 participants, the reference CD4 count (percentage of CD4) range for adult was 400 to 1288 cells/mm³ (19%-48%) and for children was 582 to 3652 cells/mm³ (17%-50%). CD4 count and percentage of CD4 were significantly ( P = .001) higher in females than in males, and the CD4 count declined significantly with increasing age ( r = -.174, P ≤ .0001). The percentage of CD4 count shows less variation with age ( r = -.051, P = .076). Adult residents of Ilorin had significantly lower absolute mean CD4 count (808 ± 260) than that of the national reference values of 847.0 ± 307.0 cells/mm³ ( P = .001).

CONCLUSION

We therefore advocate the use of CD4 count range derived in this study is lower than that of the national reference values.

Normal laboratory reference intervals among healthy adults screened for a HIV pre-exposure prophylaxis clinical trial in Botswana

INTRODUCTION

Accurate clinical laboratory reference values derived from a local or regional population base are required to correctly interpret laboratory results. In Botswana, most reference intervals used to date are not standardized across clinical laboratories and are based on values derived from populations in the United States or Western Europe.

METHODS

We measured 14 hematologic and biochemical parameters of healthy young adults screened for participation in the Botswana HIV Pre-exposure Prophylaxis Study using tenofovir disoproxil fumarate and emtricitabine (TDF/FTC) (TDF2 Study). Reference intervals were calculated using standard methods, stratified by gender, and compared with the site-derived reference values used for the TDF2 study (BOTUSA ranges), the Division of AIDS (DAIDS) Grading Table for Adverse Events, the Botswana public health laboratories, and other regional references.

RESULTS

Out of 2533 screened participants, 1786 met eligibility criteria for participation in study and were included in the analysis. Our reference values were comparable to those of the Botswana public health system except for amylase, blood urea nitrogen (BUN), phosphate, total and direct bilirubin. Compared to our reference values, BOTUSA reference ranges would have classified participants as out of range for some analytes, with amylase (50.8%) and creatinine (32.0%) producing the highest out of range values. Applying the DAIDS toxicity grading system to the values would have resulted in 45 and 18 participants as having severe or life threatening values for amylase and hemoglobin, respectively.

CONCLUSION

Our reference values illustrate the differences in hematological and biochemical analyte ranges between African and Western populations. Thus, the use of western-derived reference laboratory values to screen a group of Batswana adults resulted in many healthy people being classified as having out-of-range blood analytes. The need to establish accurate local or regional reference values is apparent and we hope our results can be used to that end in Botswana.

Population-based CD4 counts in a rural area in South Africa with high HIV prevalence and high antiretroviral treatment coverage

Background

Little is known about the variability of CD4 counts in the general population of sub-Saharan Africa countries affected by the HIV epidemic. We investigated factors associated with CD4 counts in a rural area in South Africa with high HIV prevalence and high antiretroviral treatment (ART) coverage.

Methods

CD4 counts, health status, body mass index (BMI), demographic characteristics and HIV status were assessed in 4990 adult resident participants of a demographic surveillance in rural KwaZulu-Natal in South Africa; antiretroviral treatment duration was obtained from a linked clinical database. Multivariable regression analysis, overall and stratified by HIV status, was performed with CD4 count levels as outcome.

Results

Median CD4 counts were significantly higher in women than in men overall (714 vs. 630 cells/µl, p<0.0001), both in HIV-uninfected (833 vs. 683 cells/µl, p<0.0001) and HIV-infected adults (384.5 vs. 333 cells/µl, p<0.0001). In multivariable regression analysis, women had 19.4% (95% confidence interval (CI) 16.1–22.9) higher CD4 counts than men, controlling for age, HIV status, urban/rural residence, household wealth, education, BMI, self-reported tuberculosis, high blood pressure, other chronic illnesses and sample processing delay. At ART initiation, HIV-infected adults had 21.7% (95% CI 14.6–28.2) lower CD4 counts than treatment-naive individuals; CD4 counts were estimated to increase by 9.2% (95% CI 6.2–12.4) per year of treatment.

Conclusions

CD4 counts are primarily determined by sex in HIV-uninfected adults, and by sex, age and duration of antiretroviral treatment in HIV-infected adults. Lower CD4 counts at ART initiation in men could be a consequence of lower CD4 cell counts before HIV acquisition.

Comparison of two methodologies for CD4⁺ T lymphocytes relative counting on immune monitoring of patients with human immunodeficiency virus

Considering that counting the percentage of CD4 T lymphocytes can add prognostic information regarding patients infected with HIV, the aim of this study was to evaluate the percentage values of CD4+ T lymphocytes from 81 patients determined by flow cytometry and estimated by flow cytometry in conjunction with a hematology counter. Means were compared through the Student's t-test. Pearson's correlation was determined, and the agreement between results was tested by Bland-Altman. The level of significance was P < 0.05. It was found a significantly higher mean difference between the relative values of CD4+ T lymphocytes to the hematologic counter (P < 0.05), for all strata studied. Positive and significant correlations (P < 0.01) were found between the strata CD4 < 200 cells/mL (r = 0.93), between 200 and 500 cells/mL (r = 0.65), and >500 cells/mL (r = 0.81). The limits of agreement were 1.0 ± 3.8% for the stratum of CD4 < 200 cells/mL, approximately 2.2 ± 13.5% for the stratum of CD4 between 200 and 500 cells/mL, and approximately 6.2 ± 20.4% for the stratum > 500 cells/mL. The differences in the percentages of CD4+ T lymphocytes obtained by different methodologies could lead to conflict when used in clinical decisions related to the treatment and care of people infected with HIV.

CD4- and CD3-T lymphocyte reference values of immunocompetent urban and rural subjects in an African nation

Studies on the reference values of CD4 and CD3 T cells in healthy individuals have continued to gain significance because of the importance of these immunological markers in the initiation of combination antiretroviral therapy (cART). The aim of the present study was to determine and compare the reference values of CD4 and CD3 T cells in urban and rural Nigerians who were human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) negative. After ethical clearance and informed consent, 1123 subjects who met the inclusion criteria [mean age = 24.4 (± 11.2) years] were recruited in this study. Blood samples were analysed using the BD FACScount cytometer according to the manufacturer's instructions. Of the overall 1123 subjects, reference means of CD4, CD3 and CD4/CD3 ratio were 1030 ± 367, 1757 ± 609 cells/μl and 0.59 ± 0.08, respectively. Five hundred and fifty-one (49.1%) were an urban population with the mean CD4, CD3 and CD4/CD3 T cell ratio of 1032 ± 369, 1761 ± 612 cells/μl and 0.59 (±0.08), respectively. The remaining 572 (50.9%) were of a rural population with the mean CD4, CD3 and CD4/CD3 T cell ratio of 1028 ± 459, 1753 ± 958 cells/μl and 0.59 ± 0.13, respectively. Subjects with higher CD4 and CD3 T cells were more likely to be female than male (P < 0.05). There was no significant difference between the T cell values of the two populations (P > 0.05). Our findings provide new insight in the CD4 and CD3 T cell reference values of Nigerians.

Hematoimmunological profile at gilgel gibe field research center, southwest ethiopia

BACKGROUND

Health and disease can only be distinguished by accurate and reliable reference values of a particular laboratory test. In interpreting laboratory test results, usually the reported values are compared with established reference values from developed countries. Now it is a fact that there is considerable variation in hematology reference intervals by several variables. However, such data at a population level are scanty in the Ethiopian situation. Therefore, this study was conducted to determine the hematological and immunological values in a community setting.

METHODS

A population-based cross-sectional study was conducted in Gilgel Gibe Field Research Center (GGFRC) from late September 2008 to end of January 2009. A tsample of 1,965 individuals was included in the study. Blood sample was collected by vacutainer tube and transported to Jimma University Specialized Hospital laboratory. Data were entered in to EpiData and analyzed using SPSS for Windows version 16.0 and STATA 11.

RESULTS

A total of 1965 (955 men and 1010 women) individuals were studied. The mean red blood cell count for men and women was 4.55 × 10(12)/L and 4.34 × 10(12)/L (95 percentile range between 2.9 and 5.7 × 10(12)/L) and 4.34 ×10(12)/L (95 percentile range between 2.8 and 5.2 × 10(12)/L), respectively. On the other hand, the red blood cell count of 95% of the men and women lied between 2.9-5.7 × 10(12) cells/L and 2.8-5.2 × 10(12) cells /L, respectively. The mean hemoglobin value for men was 13.6 gm/dl and for women 12.7 gm/dl. The mean corpuscular volume for men and women was 90.2 fl and 90.8 fl, respectively. The mean platelet value for men was 229.1 ×10(9) cells/L and for women 241.3 ×10(9) cells/L. The mean white blood cells count for men and women was 6.08 ×10(9) cells/L and 6.12 ×10(9) cells/L, respectively. The mean CD4 value was 809 cell/µl for men and 868 cell /µl for women. Forty two percent of the study participants had O blood group.

CONCLUSION

The hematologic and immunologic profile of the studied population in Southwest Ethiopia is different from the reports from other countries and the standards described in western literature. We recommend conducting similar nationwide study to determine the immunological and hematological reference values of the Ethiopian population as a whole.

Immunohaematological reference values for HIV-negative healthy adults in Botswana

Background

Clinical laboratories in Botswana have relied entirely on the reference intervals for normal immunohaematological values provided by manufacturers’ kits and textbooks.

Objectives

The aim of this study was to determine the means, medians, 2.5th and 97.5th percentile reference intervals, for normal immunohaematological values in healthy adults in Botswana.

Method

A total of 261 healthy participants comprising 126 men (48%) and 135 (52%) women were enrolled in the southern part of Botswana, and immunological and haematological laboratory parameters were measured.

Results

The mean age was 28.8 (95% Confidence Interval [CI] 27.7–29.8) years, with a median of 27 years and a range 18–66 years. The mean haemoglobin level was significantly lower for women (12.4 g/dL; 95% CI 12.1% – 12.7%) than men (15.1 g/dL; 95% CI 14.9% – 15.3%). The women’s haemoglobin reference values (9.0 g/dL – 15.0 g/dL) levels were lower than observed in predominantly White populations (12.0 g/dL – 16.0 g/dL), but comparable with regional consensus reference intervals (9.5 g/dL – 15.8 g/dL) recently defined for East and Southern Africa.

Conclusion

The established values provide an important tool for patient management and could influence decisions on inclusion of participants and adverse events in clinical trials conducted locally.

Establishment of reference CD4+ T cell values for adult Indian population

BACKGROUND

CD4+ T lymphocyte counts are the most important indicator of disease progression and success of antiretroviral treatment in HIV infection in resource limited settings. The nationwide reference range of CD4+ T lymphocytes was not available in India. This study was conducted to determine reference values of absolute CD4+ T cell counts and percentages for adult Indian population.

METHODS

A multicentric study was conducted involving eight sites across the country. A total of 1206 (approximately 150 per/centre) healthy participants were enrolled in the study. The ratio of male (N = 645) to female (N = 561) of 1.14:1. The healthy status of the participants was assessed by a pre-decided questionnaire. At all centers the CD4+ T cell count, percentages and absolute CD3+ T cell count and percentages were estimated using a single platform strategy and lyse no wash technique. The data was analyzed using the Statistical Package for the Social Scientist (SPSS), version 15) and Prism software version 5.

RESULTS

The absolute CD4+ T cell counts and percentages in female participants were significantly higher than the values obtained in male participants indicating the true difference in the CD4+ T cell subsets. The reference range for absolute CD4 count for Indian male population was 381-1565 cells/μL and for female population was 447-1846 cells/μL. The reference range for CD4% was 25-49% for male and 27-54% for female population. The reference values for CD3 counts were 776-2785 cells/μL for Indian male population and 826-2997 cells/μL for female population.

CONCLUSION

The study used stringent procedures for controlling the technical variation in the CD4 counts across the sites and thus could establish the robust national reference ranges for CD4 counts and percentages. These ranges will be helpful in staging the disease progression and monitoring antiretroviral therapy in HIV infection in India.

Normal Range of CD4 Cell Counts and Temporal Changes in Two HIVNegative Malawian Populations

Longitudinal studies were carried out to determine trends in CD4 cell counts over a four year period in healthy HIV-negative adults in a rural (134 individuals) and an urban (80 individuals) site in Malawi, using TruCountTM and FACScountTM platforms. At baseline, median counts and 95% ranges were 890 (359-1954) cells per microlitre (μl) and 725 (114-1074) cells/μl respectively. 1.5% and 6% respectively had baseline counts below 350 cells/μl and 1.5% and 2.5% below 250 cells per μl. Transient dips to below 250 cells/μl were observed in seven individuals, with two individuals having persistently low CD4 counts over more than one year. Women and individuals from the urban site were significantly more likely to have "low CD4 count" (< 500 cells/μl) even when adjusted for other factors. In common with neighbouring countries, HIV-negative populations in Malawi have CD4 counts considerably lower than European reference ranges, and healthy individuals may have persistently or transiently low counts. Within Malawi, ranges differ according to the selected population.

A review on peripheral blood CD4+ T lymphocyte counts in healthy adult Indians

The CD4+ T lymphocytes are the crucial cells in the cascade of events in forming immune response to the foreign antigen and hence monitoring the CD4+ T cell counts to understand the extent of immune deficiency is a common practice. CD4+ T cells are also the primary target cells for human immunodeficiency virus (HIV). Hence CD4+ T lymphocyte count is the most important marker of immune dysfunction in HIV disease progression. The estimation of CD4+ T cell counts is used to decide the initiation of anti retroviral therapy (ART), to monitor the efficacy of ART and to start treatment for opportunistic infections (OIs). To develop the threshold levels of CD4+ T cell counts, data from western countries are being used in India. The CD4+ T cell counts are known to be influenced by race and environmental factors. Hence it is important to establish the reference ranges for the CD4+ T cell counts in the target population to understand the immune dysfunction. The information on the lower limits of the CD4+ T cells count is necessary to decide the initiation and monitoring of ART. The published data on the CD4+ T cells count in healthy Indian adult population have been reviewed, analyzed and discussed in this review article. The requirement of establishment of reference ranges in Indian population is discussed.

Antiretroviral therapy for tuberculosis control in nine African countries

HIV has increased the incidence of tuberculosis (TB) by up to sevenfold in African countries, but antiretroviral therapy (ART) reduces the incidence of AIDS-related TB. We use a mathematical model to investigate the short-term and long-term impacts of ART on the incidence of TB, assuming that people are tested for HIV once a year, on average, and start ART at a fixed time after HIV seroconversion or at a fixed CD4(+) cell count. We fit the model to trend data on HIV prevalence and TB incidence in nine countries in sub-Saharan Africa. If HIV-positive people start ART within 5 y of seroconversion, the incidence of AIDS-related TB in 2015 will be reduced by 48% (range: 37-55%). Long-term reductions depend sensitively on the delay to starting ART. If treatment is started 5, 2, or 1 y after HIV seroconversion, or as soon as people test positive, the incidence in 2050 will be reduced by 66% (range: 57-80%), 95% (range: 93-96%), 97.7% (range: 96.9-98.2%) and 98.4% (range: 97.8-98.9%), respectively. In the countries considered here, early ART could avert 0.71 ± 0.36 [95% confidence interval (CI)] million of 3.4 million cases of TB between 2010 and 2015 and 5.8 ± 2.9 (95% CI) million of 15 million cases between 2015 and 2050. As more countries provide ART at higher CD4(+) cell counts, the impact on TB should be investigated to test the predictions of this model.

Frequency of long-term nonprogressors in HIV-1 seroconverters From Rakai Uganda

OBJECTIVE

Studies on long-term nonprogressors (LTNP) have been conducted in the USA and Europe. This study examined the frequency of LTNPs and HIV controllers among 637 HIV-1 seroconverters in rural Uganda.

DESIGN AND METHODS

LTNPs were defined as being infected for more than 7 years with a CD4 T-cell count above 600 cells per microliter, and HIV controllers as having undetectable viral loads on 3 separate occasions without antiretroviral treatment. HIV-1 viral load and subtype distribution between LTNP and non-LTNP populations were determined.

RESULTS

Of the HIV seroconverters, 9.1% (58/637) were LTNPs and 1.4% (9/637) were HIV controllers. LTNPs had a significantly lower viral load at set point than non-LTNP participants (P < 0.001). The Kaplan-Meier joint probability of surviving to 7 years with a CD4 count >600 was 19.2%. Individuals who survived 7 years had a significantly higher frequency of HIV-1 subtype A (P < 0.05), but seroconverters infected with HIV-1A did not have a significantly higher probability of becoming an LTNP.

CONCLUSIONS

The frequency of LTNPs appears to be relatively high in Uganda and it may be important to take this into account when designing studies of viral pathogenesis and performing HIV vaccine trials in sub-Saharan Africa.

Immunohaematological reference values in human immunodeficiency virus-negative adolescent and adults in rural northern Tanzania

Background

The amount of CD4 T cells is used for monitoring HIV progression and improvement, and to make decisions to start antiretroviral therapy and prophylactic drugs for opportunistic infections. The aim of this study was to determine normal reference values for CD4 T cells, lymphocytes, leucocytes and haemoglobin level in healthy, HIV negative adolescents and adults in rural northern Tanzania.

Methods

A cross sectional study was conducted from September 2006 to March 2007 in rural northern Tanzania. Participants were recruited from voluntary HIV counselling and testing clinics. Patients were counselled for HIV test and those who consented were tested for HIV. Clinical screening was done, and blood samples were collected for CD4 T cell counts and complete blood cell counts.

Results

We enrolled 102 participants, forty two (41.2%) males and 60 (58.8%) females. The mean age was 32.6 ± 95% CI 30.2–35.0. The mean absolute CD4 T cell count was 745.8 ± 95% CI 695.5–796.3, absolute CD8 T cells 504.6 ± 95% CI 461.7–547.5, absolute leukocyte count 5.1 ± 95% CI 4.8–5.4, absolute lymphocyte count 1.8 ± 95% CI 1.7–1.9, and haemoglobin level 13.2 ± 95% CI 12.7–13.7. Females had significantly higher mean absolute CD4 T cell count (p = 0.008), mean absolute CD8 T cell count (p = 0.009) and significantly lower mean haemoglobin level than males (p = 0.003)

Conclusion

Immunohaematological values found in this study were different from standard values for western countries. Females had significantly higher mean CD4 T cell counts and lower mean haemoglobin levels than males. This raises the issue of the appropriateness of the present reference values and guidelines for monitoring HIV/AIDS patients in Tanzania.

Reference ranges for the clinical laboratory derived from a rural population in Kericho, Kenya

The conduct of Phase I/II HIV vaccine trials internationally necessitates the development of region-specific clinical reference ranges for trial enrollment and participant monitoring. A population based cohort of adults in Kericho, Kenya, a potential vaccine trial site, allowed development of clinical laboratory reference ranges. Lymphocyte immunophenotyping was performed on 1293 HIV seronegative study participants. Hematology and clinical chemistry were performed on up to 1541 cohort enrollees. The ratio of males to females was 1.9:1. Means, medians and 95% reference ranges were calculated and compared with those from other nations. The median CD4+ T cell count for the group was 810 cells/microl. There were significant gender differences for both red and white blood cell parameters. Kenyan subjects had lower median hemoglobin concentrations (9.5 g/dL; range 6.7-11.1) and neutrophil counts (1850 cells/microl; range 914-4715) compared to North Americans. Kenyan clinical chemistry reference ranges were comparable to those from the USA, with the exception of the upper limits for bilirubin and blood urea nitrogen, which were 2.3-fold higher and 1.5-fold lower, respectively. This study is the first to assess clinical reference ranges for a highland community in Kenya and highlights the need to define clinical laboratory ranges from the national community not only for clinical research but also care and treatment.

Reference ranges for the clinical laboratory derived from a rural population in Kericho, Kenya

The conduct of Phase I/II HIV vaccine trials internationally necessitates the development of region-specific clinical reference ranges for trial enrolment and participant monitoring. A population based cohort of adults in Kericho, Kenya, a potential vaccine trial site, allowed development of clinical laboratory reference ranges. Lymphocyte immunophenotyping was performed on 1293 HIV seronegative study participants. Hematology and clinical chemistry were performed on up to 1541 cohort enrollees. The ratio of males to females was 1.9∶1. Means, medians and 95% reference ranges were calculated and compared with those from other nations. The median CD4+ T cell count for the group was 810 cells/µl. There were significant gender differences for both red and white blood cell parameters. Kenyan subjects had lower median hemoglobin concentrations (9.5 g/dL; range 6.7–11.1) and neutrophil counts (1850 cells/µl; range 914–4715) compared to North Americans. Kenyan clinical chemistry reference ranges were comparable to those from the USA, with the exception of the upper limits for bilirubin and blood urea nitrogen, which were 2.3-fold higher and 1.5-fold lower, respectively. This study is the first to assess clinical reference ranges for a highland community in Kenya and highlights the need to define clinical laboratory ranges from the national community not only for clinical research but also care and treatment.

Clinical applications and availability of CD4+ T cell count testing in sub-Saharan Africa

The absolute CD4+ T cell count in adults and CD4+ T cell percentage of lymphocytes (CD4%) in pediatrics compliment clinical history and physical examination to inform decisions about initiating antiretroviral therapy (ART). In addition, these immunologic markers predict host susceptibility to specific opportunistic infections, selected drug toxicities, and mortality. These benefits argue strongly for the availability of CD4+ T cell testing capacity in all settings where HIV infection is treated. Several currently available flow cytometry-based devices, and novel CD4+ T cell enumeration techniques such as the panleucogating CD4 are especially suitable for resource-constrained settings. At this time, unfortunately, the landscape of HIV care in sub-Saharan Africa is a mosaic characterized by large areas where CD4+ T cell testing capacity is limited or unavailable, and small, but growing, pockets where the capacity exists. Routine HIV quantification is currently unaffordable and unsustainable in the great majority of the region; therefore, a reliance on CD4+ T cell testing is inevitable for now. To this end, correcting the disparities in CD4+ T cell testing capacity and defining the minimum laboratory requirements for the safe use of antiretroviral drugs through well-designed clinical studies are some of the most urgent priorities of the ongoing global scale-up of ART.

Factors associated with CD4 lymphocyte counts in HIV-negative Senegalese individuals

CD4+ lymphocytes are a primary target of the human immunodeficiency virus (HIV), and CD4 counts are one of the factors used to measure disease progression in HIV-positive individuals. CD4 counts vary in uninfected individuals and across populations due to a variety of demographic, environmental, immunological and genetic factors that probably persist throughout the course of HIV infection. This study sought to determine reference levels and identify factors that influence lymphocyte counts in 681 HIV-uninfected adults in Senegal, where residents are exposed to a variety of infectious diseases and other conditions that may affect CD4 counts. Lymphocyte counts were assessed in commercial sex workers, symptomatic men and women presenting to the University of Dakar infectious disease clinic for out-patient care and women seeking family planning services. CD4 and CD3 lymphocyte counts differed between the four study groups (P < 0.01). Men had the lowest mean CD4 count (711.6 cells/microl), while commercial sex workers had the highest levels (966.0 cells/microl). After adjustment for age and other behavioural and clinical factors, the difference in CD4 counts between the three groups of women did not remain. However, both gender and smoking were associated independently with CD4 counts, as men maintained lower mean CD4 counts (beta = -156.4 cells/microl, P < 0.01) and smokers had higher mean CD4 counts (beta = 124.0 cells/microl, P < 0.01) than non-smokers in multivariable analyses. This study is the first to explore factors that may influence CD4 levels in Senegal and to estimate baseline CD4 levels among HIV-negatives, information that may guide clinicians in interpreting CD4 counts.

Characterization of drug Resistance in Antiretroviral-Treated Patients Infected with HIV-1 CRF02_AG and AGK Subtypes in Mali and Burkina Faso

Background

In a multicentred cohort of patients on antiretroviral therapy (ART) in Burkina Faso and Mali, we analysed the prevalence of HIV drug resistance mutations in patients failing a modified directly observed therapy (mDOT) protocol.

Methods

Patients on ART >6 months and with viral load (VL) >500 copies/ml were enrolled in a mDOT protocol. Genotypic resistance testing was performed on pre- and post-mDOT plasma samples of patients who still had VL >500 copies/ml after mDOT.

Results

Eight hundred and one patients from seven sites participated in the study. One hundred and thirteen patients (14.1%) had VL >500 copies/ml. Most patients were treated with lamivudine along with zidovudine or stavudine and efavirenz or nevirapine. Genotypes were available for 46 patients. The predominant HIV-1 subtypes were CRF02_AG in 26 (56.5%) and AGK/K/AK in 12 (26.1%) patients. The prevalence of drug resistance mutations by class were as follows for nucleoside reverse transcriptase inhibitors: 184I/V (82.6%), 215Y/F (32.6%), 219E/Q (19.6%), 70R (19.6%), 67N (21.7%), 41L (15.2%) and 151M(2.2%). For non-nucleoside reverse transcriptase inhibitors the prevalence was: 103N (50%) and 181C/I (19.6%). Phylogenetic analysis showed that, although the genetic distances were small among isolates, there was no clustering of a particular subtype in a specific region and that the high prevalence of AGK subtype in our drug-resistant population was not due to a circulating resistant strain.

Conclusion

Although CRF02_AG is the dominant clade in the Burkina Faso/Mali region, isolates with subtype K reverse transcriptase were frequent in our cohort. Drug resistance mutation pathways in subtype K reverse transcriptase need to be further evaluated in a larger cohort of non-B HIV-infected individuals.

Effects of HIV type 1 infection on hematopoiesis in Botswana

Clinical observations suggest that HIV-1 infection causes higher anemia rates in patients in southern Africa than in those in the United States. To explore this difference we performed a cross-sectional exploratory study on the effect of HIV-1 infection on hematopoiesis in Botswana by examining hematological presentation, HIV disease state, hematopoietic progenitor cell number, and circulating viral levels in HIV-infected patients and HIV-uninfected controls. We found significant associations between CD34(+) and CD4(+) cell counts in HIV-positive patients. Significant relationships were also seen between the CD34(+) CD4(+) cell population and hemoglobin levels, as well as colony-forming ability. These associations, however, were not seen in uninfected controls. Circulating viral p24 levels were found to correlate significantly with CD34(+) cell count, CD34(+) CD4(+) cell count, and colony-forming ability. These results demonstrate a direct association between HIV-1 infection in southern Africa and hematopoietic progenitor cell health.

Normal CD4+ T Lymphocyte Levels in HIV Seronegative Individuals in the Manya/Yilo Krobo Communities in the Eastern Region of Ghana

The goal of this study was to determine the normal levels of CD4+ T lymphocytes in healthy individuals who were HIV seronegative in the Manya and Yilo Krobo Districts of Ghana's Eastern Region. This enabled comparisons with normal CD4 count ranges established by the World Health Organization (WHO). The study population consisted of 249 HIV-seronegative clients from a mobile free Voluntary Counseling and Testing (VCT) service in communities of the two districts during a one-month period. The mean CD4 count of these individuals was 1067 cells/microl with women demonstrating higher baseline CD4 counts than men. This study found a WHO comparable HIV seronegative baseline CD4 count as well as gender-based differences in the CD4 count and CD4/CD8 ratio. Establishment of the adult baseline for the country provides important demographic data and indicates the appropriateness of current global treatment guidelines with regards to CD4 levels in Ghana.