Establishment of reference values of CD4 and CD8 lymphocyte subsets in healthy Nigerian adults

Reference Intervals for Absolute and Percentage CD4+ T Lymphocytes among an Apparently Healthy Population in Addis Ababa, Ethiopia

Background

Reference intervals for clinical laboratory parameters differ based on several factors, including age, sex, genetic variation, and geographic location. This variation influences clinical decisions and treatment monitoring. Currently, Ethiopia has used adopted reference intervals from manufacturer values derived from non-Africans. Therefore, the aim this study was to determine reference intervals for absolute and percentage CD4⁺ T cells for an apparently healthy population in Addis Ababa, Ethiopia.

Methods

A community-based cross-sectional study was conducted on 361 apparently healthy people in four subcities in Addis Ababa from January to June 2019. Sociodemographic and clinical data were collected using a structured questionnaire after informed consent had been obtained. Blood samples were collected and CD4⁺ T-lymphocyte enumeration performed using a BD FACSPresto near-patient CD4 counter. Data were entered and analyzed using SPSS 20. Reference intervals were determined by a nonparametric test estimating percentiles 2.5 (lower limit) and 97.5 (upper limit) with 95% CIs. P<0.05 was considered statistically significant.

Results

A total of 337 (183 female and 154 male) healthy participants of median age 28 (IQR 17–35) years were included in the final analysis. Medians of absolute and percentage CD4⁺ T-cell counts (932.0 and 42.9, respectively) of female participants were significantly higher than male participants (802.5 and 38.7, respectively; P<0.05). Reference intervals for absolute CD4⁺ T-cell count and percentages in males were 483.8–1,310 cells/µL and 18.1–57.3 and in females 447.8–1,479.8 cells/µL and 25.6–58.9, respectively.

Conclusion

The CD4⁺ T-count reference intervals established in this study showed some inconsistency from the manufacturer’s provided values and other studies and also revealed sex differences, necessitating sex-specific locally established reference intervals.

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.

Age-related differences in T cell subsets in a nationally representative sample of people over age 55: Findings from the Health and Retirement Study

Though T cell immunosenescence is a major risk factor for age-related diseases, susceptibility to infections, and responses to vaccines, differences in T cells subset counts and representation by age and sex have not been determined for a large sample representative of the national population of the US. We evaluated the counts of T cell subsets including total, CD4+ and CD8+ T cells, and their naïve (Tn), effector memory (Tem) and effector subsets, in the context of age, sex and exposure to cytomegalovirus (CMV) infection among 8,848 Health and Retirement Study (HRS) participants, a nationally representative study of adults over 55 years. Total T cells (CD3+) and CD4+ cells declined markedly with age; CD8+ T cells declined somewhat less. While CD4+ T cell declines with age occurred for both CMV seropositive and CMV seronegative groups, total T cells and CD8+ cells were both substantially higher among the CMV seropositive group. Numbers of Tn CD4+ and CD8+ cells were strongly and inversely related to age, were better conserved among women, and were independent of CMV seropositivity. By contrast, accumulation of the CD8+ and CD4+ Tem and effector subsets was CMV-associated. This is the first study to provide counts of T cell subsets by age and sex in a national sample of older US adults over the age of 55 years. Understanding T cell changes with age and sex is an important first step in determining strategies to reduce its impact on age-related diseases and susceptibility to infection.

Characteristics of and reference ranges for peripheral blood lymphocytes and CD4 T cell subsets in healthy adults in Shanxi Province, North China

Objective

To guide clinical decision making, race-, age- and gender-specific reference ranges for lymphocytes and CD4+ T-cell subsets are required.

Methods

Single platform flow cytometry to determine reference intervals for lymphocyte subpopulations and CD4+ T-cell subsets in 196 healthy Han Chinese adults.

Results

The frequencies and absolute numbers of B cells were slightly lower in Han Chinese individuals of the Shanxi region than in individuals from Hong Kong, Germany and Singapore, while percentages and absolute numbers of NK cells were slightly higher compared with individuals from Hong Kong. CD4+/CD8+ T-cell ratios, CD4+ T cell percentages and Th2 cell counts were higher, while frequencies and numbers of CD8+ T cells, numbers of NK cells and percentages of Th1 cells were lower, in females compared with males. CD4+ T cell percentages, CD4+/CD8+ T-cell ratios, numbers of CD8+ T cells and Treg cells, and Th17/Treg cell ratios differed by age.

Conclusion

We established lymphocyte and CD4+ T-cell subset reference intervals for healthy Han Chinese adults of the Shanxi region. Ethnicity, gender and age affected lymphocyte subset composition.

A mechanistic model for long-term immunological outcomes in South African HIV-infected children and adults receiving ART

Long-term effects of the growing population of HIV-treated people in Southern Africa on individuals and the public health sector at large are not yet understood. This study proposes a novel ‘ratio’ model that relates CD4+ T-cell counts of HIV-infected individuals to the CD4+ count reference values from healthy populations. We use mixed-effects regression to fit the model to data from 1616 children (median age 4.3 years at ART initiation) and 14,542 adults (median age 36 years at ART initiation). We found that the scaled carrying capacity, maximum CD4+ count relative to an HIV-negative individual of similar age, and baseline scaled CD4+ counts were closer to healthy values in children than in adults. Post-ART initiation, CD4+ growth rate was inversely correlated with baseline CD4+ T-cell counts, and consequently higher in adults than children. Our results highlight the impacts of age on dynamics of the immune system of healthy and HIV-infected individuals.

The human immunodeficiency virus (HIV) remains an ongoing global pandemic. There is currently no cure for HIV, but antiretroviral therapies can keep the virus in check and allow individuals with HIV to live longer, healthier lives. These drugs work in two ways. They block the ability of the virus to multiply and they allow numbers of an important type of infection-fighting cell called CD4+ T cells to rebound.

As more patients with HIV survive and transition from one life stage to the next, it is critical to understand how long-term antiretroviral therapies will affect normal age-related changes in their immune systems. The health of an immune system can be evaluated by looking at the number of CD4+ T cells an individual has, though this will vary by age and location. Clinicians use the same metrics to assess the immune health of individuals with HIV, however, as they age, it becomes a challenge to identify if a patient’s immune system recovers normally or insufficiently. Thus, learning more about age-related differences in CD4+ T cells in people living with HIV may help improve their care.

Using data from 1,616 children and 14,542 adults from South Africa, Ujeneza et al. created a simple mathematical model that can compare the immune system of person with HIV with the immune system of a similarly aged healthy individual. The model shows that among individuals with HIV receiving antiretroviral therapies, children have CD4+ T-cell numbers that are closest to the numbers seen in healthy individuals of the same age. This suggests that children may be more able to recover immune system function than adults after beginning treatment. Children also start antiretroviral therapies before their immune system has been severely damaged, while adults tend to start treatment much later when they have fewer CD4+ T cells left.

Ujeneza et al. show that the fewer CD4+ T cells a person has when they start treatment, the faster the number of these cells grows after starting treatment. This suggests that the more damaged the immune system is, the harder it works to recover. This reinforces the need to identify people infected with HIV as soon as possible through testing and to begin treatment promptly. The new model may help clinicians and policy makers develop screening and treatment protocols tailored to the specific needs of children and adults living with HIV.

Establishment of reference range of CD4 T-lymphocyte in healthy Nepalese adults

Objective

CD4 T lymphocytes are the most widely used cellular markers to assess the course of HIV infection, clinical staging and, monitoring the effect of antiretroviral therapy. The regional reference range for Eastern, Central and Western development region of Nepal had already been established whereas the same was still lacking in Mid-western and Far-western development region. The objective of this study was to establish reference range of CD4 T lymphocyte in the remaining two development regions and finally the national reference range using data from previous study.

Results

The average values (mean ± SD) of CD4 and CD3 T cell in present study was (819 ± 294) cells/μl and (1546 ± 532) cells/μl, respectively. The absolute CD4 T cell (914 ± 303) and CD3 T cell (1671 ± 560) count in female were significantly higher than those from male, CD4 (757 ± 270) and CD3 (1465 ± 499) (p value-0.000). National reference value of CD4 was determined to be (798 ± 335) cells/μl for healthy Nepalese adults.

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.

Establishment of normative ranges of the healthy human immune system with comprehensive polychromatic flow cytometry profiling

Existing normative flow cytometry data have several limitations including small sample sizes, incompletely described study populations, variable flow cytometry methodology, and limited depth for defining lymphocyte subpopulations. To overcome these issues, we defined high-dimensional flow cytometry reference ranges for the healthy human immune system using Human Immunology Project Consortium methodologies after carefully screening 127 subjects deemed healthy through clinical and laboratory testing. We enrolled subjects in the following age cohorts: 18–29 years, 30–39, 40–49, and 50–66 and enrolled cohorts to ensure an even gender distribution and at least 30% non-Caucasians. From peripheral blood mononuclear cells, flow cytometry reference ranges were defined for >50 immune subsets including T-cell (activation, maturation, T follicular helper and regulatory T cell), B-cell, and innate cells. We also developed a web tool for visualization of the dataset and download of raw data. This dataset provides the immunology community with a resource to compare and extract data from rigorously characterized healthy subjects across age groups, gender and race.

Establishment of reference values for selected haematological parameters in young adult Nigerians

Background

Haematological reference values are necessary for accurate diagnosis of diseases, clinical decision-making, treatment monitoring and clinical research. Due to unavailability of pan-Nigerian reference values, local results interpretation is based on the use of Western values.

Objective

This study aims to establish national reference values for some haematological parameters in apparently healthy young adult Nigerians.

Methods

Seven Thousand, Seven Hundred and Ninety-Seven (7,797) volunteers aged 18 to 26 years participated in the study. Participants’ interviewer-administered questionnaires and blood samples were collected, analyzed and those with confounding factors (HIV infection, Hepatitis B sero-positivity, Malaria and Pregnancy) were excluded from statistical analysis. The 95-percentile reference range was determined for each haematological parameter using SPSS Version 16^®. The result obtained was reviewed with reference to already established reference values in two West African and Western countries.

Results

Blood specimens from 6153 (78.9%) participants [comprising 5915 (96.1%) males and 238 (3.9%) females] were analyzed after exclusion of 1,644 (21.1%) participants with confounding variables. Reference ranges among males and females varied and these were consistent with findings from two other West African countries. The median platelets count in this study was 218 x 10⁹/l while commonly used Western value is 280 x 10⁹/l. Other haematological parameters in the study were similar to Western values.

Conclusion

The findings of this study will improve clinical and research decision-making. Considering that this study is limited to young adult participants, there is a need to conduct future pan-Nigerian studies that will include all age groups.

Outcomes of Nigeria's HIV/AIDS Treatment Program for Patients Initiated on Antiretroviral Treatment between 2004-2012

Background

The Nigerian Antiretroviral therapy (ART) program started in 2004 and now ranks among the largest in Africa. However, nationally representative data on outcomes have not been reported.

Methods

We evaluated retrospective cohort data from a nationally representative sample of adults aged ≥15 years who initiated ART during 2004 to 2012. Data were abstracted from 3,496 patient records at 35 sites selected using probability-proportional-to-size (PPS) sampling. Analyses were weighted and controlled for the complex survey design. The main outcome measures were mortality, loss to follow-up (LTFU), and retention (the proportion alive and on ART). Potential predictors of attrition were assessed using competing risk regression models.

Results

At ART initiation, 66.4 percent (%) were females, median age was 33 years, median weight 56 kg, median CD4 count 161 cells/mm³, and 47.1% had stage III/IV disease. The percentage of patients retained at 12, 24, 36 and 48 months was 81.2%, 74.4%, 67.2%, and 61.7%, respectively. Over 10,088 person-years of ART, mortality, LTFU, and overall attrition (mortality, LTFU, and treatment stop) rates were 1.1 (95% confidence interval (CI): 0.7–1.8), 12.3 (95%CI: 8.9–17.0), and 13.9 (95% CI: 10.4–18.5) per 100 person-years (py) respectively. Highest attrition rates of 55.4/100py were witnessed in the first 3 months on ART. Predictors of LTFU included: lower-than-secondary level education (reference: Tertiary), care in North-East and South-South regions (reference: North-Central), presence of moderate/severe anemia, symptomatic functional status, and baseline weight <45kg. Predictor of mortality was WHO stage higher than stage I. Male sex, severe anemia, and care in a small clinic were associated with both mortality and LTFU.

Conclusion

Moderate/Advanced HIV disease was predictive of attrition; earlier ART initiation could improve program outcomes. Retention interventions targeting men and those with lower levels of education are needed. Further research to understand geographic and clinic size variations with outcome is warranted.

CD4 Decay Rate as an Indicator of the Time Interval between Initial Infection and First Diagnosis among Drug-Naïve Human Immunodeficiency Virus Seropositive Individuals in Lagos, Nigeria

OBJECTIVE

The aim of this study was to determine the time interval between human immunodeficiency virus (HIV) infection and the first diagnosis among drug-naïve individuals in Badagry, Nigeria.

SUBJECTS AND METHODS

A sample of 213 subjects who tested HIV positive for the first time were enrolled in this study. The HIV diagnosis was performed using Startpak® and Determine® kits, and a CD4 count was carried out using a FACS Count® flow cytometer. The mean CD4 values were determined by gender and age groups. The time interval between initial HIV infection and first testing was calculated based on the average CD4 decay rate per calendar year, and data analysis was performed using SPSS software.

RESULTS

At diagnosis, the mean CD4 values showed that females recorded 270 cells/µl and males 244 cells/µl. By age range, individuals <25 years recorded 437 cells/µl, those between 25 and 40 years of age had 237 cells/µl, and those aged ≥41 years had 192 cells/µl. There was a significant difference between CD4 cell categorization and age range (p < 0.001). Subjects aged between 25 and 40 years recorded the highest distribution of all CD4 cell counts. The time interval between infection and testing for females was 8.1 years and for males 6.7 years. Within the age group <25 years the interval was 5.1 years, whilst it was 8.1 years for those aged ≥41 years.

CONCLUSION

Most of the population presented for testing during the advanced stages of infection. We suggest an upscaling of HIV voluntary counseling and testing to encourage early detection and better treatment outcomes.

Reference ranges of lymphocyte subsets balanced for age and gender from a population of healthy adults in Chongqing District of China

The enumeration of lymphocyte subsets plays an essential role in the monitoring of immunological disorders. Immunophenotyping values have been found to be influenced by race, age, gender, and environmental conditions. Therefore, it is important to establish reference ranges for healthy adults from the local population for clinical decision-making. The current study aimed to establish a normal reference range for peripheral blood lymphocyte subsets in healthy adults from the Chongqing District of China by using single-platform flow cytometry. Age- and gender-specific reference ranges were established in 268 healthy adult males and females between 21 and 60 years of age. The CD8+ cell counts decreased with age, CD4+ cell percentages and counts increased with age, and total T cell percentages were higher in the female population. Our results are similar to those reported from other parts of China but different from some results reported from other countries; this further stresses the need to establish local reference ranges by region. Our results will help in the management of patients with human immunodeficiency virus and other immunological disorders in Chongqing District. © 2015 International Clinical Cytometry Society.

Potential for false-positive HIV test results using rapid HIV testing algorithms

Background

In order to scale up access to HIV counselling and testing in Nigeria, an HIV diagnostic algorithm based on rapid testing was adopted. However, there was the need to further evaluate the testing strategy in order to better assess its performance, because of the potential for false positivity.

Objectives

The objective of this study was to compare positive HIV test results obtained from the approved rapid testing algorithm with results from western blot tests performed on samples from the same patient.

Methodology

A retrospective review was conducted of HIV screening and confirmatory results for patients seen between 2007 and 2008. Rapid test and western blot results were extracted and compared for concordance. Discordant results were further reviewed using a combination of HIV-1 RNA viral load and CD4+ cell count test results and clinical presentation from medical records.

Results

Analysis of 2228 western blot results showed that 98.3% (n = 2191) were positive for HIV-1, 0.4% (n = 8) were positive for HIV-2 and 0.3% (n = 7) were dual infections (positive for both HIV-1 and HIV-2); 0.6% (n = 13) were indeterminate and 0.4% (n = 9) were negative. Further investigation of the 13 indeterminate results showed nine to be HIV-1 positive and four to be HIV-negative, for a total of 13 negative results. The positive predictive value of the HIV counselling and testing algorithm was 99.4%.

Conclusion

Using the rapid testing algorithm alone, false positives were detected. Therefore, effective measures such as training and retraining of staff should be prioritised in order to minimise false-positive diagnoses and the associated potential for long-term psychological and financial impact on the patients.

Factors influencing CD4 cell count in HIV-positive pregnant women in a secondary health center in Lagos, Nigeria

Background

Immunity in pregnancy is physiologically compromised, and this may affect CD4 count levels. It is well-established that several factors affect CD4 count level in pregnancy. This study aimed to determine the mean and reference range of CD4 count in human immunodeficiency virus (HIV)-positive pregnant women in Lagos, Nigeria.

Methods

A retrospective study was carried out at antenatal clinics of the Maternal and Child Center of a secondary health center in Lagos State, Nigeria. Records of HIV-positive pregnant women at various gestational ages, including CD4+ cell count at booking, packed cell volume (PCV) at booking and labor, gestational age at delivery, and infant weight and sex were retrieved. The descriptive data was given as mean ± standard deviation (SD). Pearson’s chi-squared test and correlation were used for analytical assessment.

Results

Data were retrieved for a total of 143 patients. The mean age was 31.15±3.78 years. The mean PCV was 31.01%±3.79% at booking and 30.49%±4.80% during labor. The mean CD4 count was 413.87±212.09 cells/μL, with a range of 40 to 1,252 cells/μL. The mean infant weight was 3.05±0.45 kg, with a range of 2 to 5 kg. Age of the mother, gestational age, and PCV at booking were not statistically significantly associated with CD4 count.

Conclusion

Maternal age, gestational age, and PCV at booking had no significant effects on CD4+ cell count levels in pregnancy. The mean CD4+ cell count of HIV-positive pregnant women in Lagos is 413.87±212.09 cells/μL.

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.

Comprehensive reference ranges for hematology and clinical chemistry laboratory parameters derived from normal Nigerian adults

BACKGROUND

Interpretation of laboratory test results with appropriate diagnostic accuracy requires reference or cutoff values. This study is a comprehensive determination of reference values for hematology and clinical chemistry in apparently healthy voluntary non-remunerated blood donors and pregnant women.

METHODS AND FINDINGS

Consented clients were clinically screened and counseled before testing for HIV, Hepatitis B, Hepatitis C and Syphilis. Standard national blood donors' questionnaire was administered to consented blood donors. Blood from qualified volunteers was used for measurement of complete hematology and chemistry parameters. Blood samples were analyzed from a total of 383 participants, 124 (32.4%) males, 125 (32.6%) non-pregnant females and 134 pregnant females (35.2%) with a mean age of 31 years. Our results showed that the red blood cells count (RBC), Hemoglobin (HB) and Hematocrit (HCT) had significant gender difference (p = 0.000) but not for total white blood count (p>0.05) which was only significantly higher in pregnant verses non-pregnant women (p = 0.000). Hemoglobin and Hematocrit values were lower in pregnancy (P = 0.000). Platelets were significantly higher in females than men (p = 0.001) but lower in pregnant women (p =  .001) with marked difference in gestational period. For clinical chemistry parameters, there was no significant difference for sodium, potassium and chloride (p>0.05) but gender difference exists for Bicarbonate (HCO3), Urea nitrogen, Creatinine as well as the lipids (p<0.05). Total bilirubin was significantly higher in males than females (p = 0.000). Significant differences exist for all chemistry parameters between pregnant and non-pregnant women in this study (p<0.05), except Amylase and total cholesterol (p>0.05).

CONCLUSIONS

Hematological and Clinical Chemistry reference ranges established in this study showed significant gender differences. Pregnant women also differed from non-pregnant females and during pregnancy. This is the first of such comprehensive study to establish reference values among adult Nigerians and difference observed underscore the need to establish reference values for different populations.

Reference values for clinical laboratory parameters in young adults in Maputo, Mozambique

Background

Clinical laboratory reference values from North American and European populations are currently used in most Africans countries due to the absence of locally derived reference ranges, despite previous studies reporting significant differences between populations. Our aim was to define reference ranges for both genders in 18 to 24 year-old Mozambicans in preparation for clinical vaccine trials.

Methods

A cross-sectional study including 257 volunteers (102 males and 155 females) between 18 and 24 years was performedat a youth clinic in Maputo, Mozambique. All volunteers were clinically healthy and human immunodeficiency virus, Hepatitis B virus and syphilis negative.Median and 95% reference ranges were calculated for immunological, hematological and chemistry parameters. Ranges were compared with those reported based on populations in other African countries and the US. The impact of applying US NIH Division of AIDS (DAIDS) toxicity tables was assessed.

Results

The immunology ranges were comparable to those reported for the US and western Kenya.There were significant gender differences in CD4⁺ T cell values 713 cells/µL in males versus 824 cells/µL in females (p<0.0001). Hematologic values differed from the US values but were similar to reports of populations in western Kenya and Uganda. The lower and upper limits of the ranges for hemoglobin, hematocrit, red blood cells, white blood cells and lymphocytes were somewhat lower than those from these African countries. The chemistry values were comparable to US values, with few exceptions. The upper limits for ALT, AST, bilirubin, cholesterol and triglycerides were higher than those from the US. DAIDStables for adverse events predicted 297 adverse events and 159 (62%) of the volunteers would have been excluded.

Conclusion

This study is the first to determine normal laboratory parameters in Mozambique. Our results underscore the necessity of establishing region-specific clinical reference ranges for proper patient management and safe conduct of clinical trials.

Cluster of differentiation 4+ cell count mean value, reference range and its influencing factors in Human Immunodeficiency Virus-seronegative pregnant women in Lagos

Background:

Immunity in pregnancy is physiologically compromised and this may affect cluster of differentiation four (CD4) count levels. It is well established that several factors affect CD4 count level in pregnancy. This study aims to determine the effects of maternal age, gestational age, parity and level of education as they influence CD4 count in pregnancy and also to determine the mean and reference range of CD4 count in pregnancy in Lagos, Nigeria.

Materials and Methods:

A descriptive cross-sectional study was carried out at Ante-natal clinics in Lagos State, Nigeria. About 5 mls of blood was collected into Ethylene Diamine Tetracetic Acid (EDTA) bottles from HIV-negative pregnant women in various gestational ages of pregnancy. CD4+ cell count and full blood count of all samples were done within 3 hours of collection. The descriptive data was given as means ± standard deviation (SD). Pearson's chi-squared test and correlation were used for analytical assessment.

Results:

A total of 74 pregnant women were recruited. The age range was 19–41 years and a mean age of 30.42 ± 5.34 years. The CD4+ cell count was not statistically significant when compared with participants ages P = 0.417, neither with gestational ages P = 0.323, nor with parity P = 0.247 nor level of education P = 0.96. An overall mean CD4+ cell count was 771.96 ± 250 cells/μl and the range was 193–1370 cells/μl.

Conclusion:

Maternal age, gestational age, parity and level of education had no significant effects on CD4+ cell count levels in pregnancy. The mean CD4+ cell count of HIV-negative pregnant women in Lagos is 771.96 ± 250 cells/μl.

CD4+ T Lymphocytes count in sickle cell anaemia patients attending a tertiary hospital

BACKGROUND

Sickle cell haemoglobin (HbS) is the commonest abnormal haemoglobin and it has a worldwide distribution. Reports have shown that patients with sickle cell anaemia (HbSS) have an increased susceptibility to infection leading to increased morbidity and mortality. Impaired leucocyte function and loss of both humoral and cell-mediated immunity are some of the mechanisms that have been reported to account for the immunocompromised state in patients with sickle cell disease. This study was carried out to determine the CD4+ T lymphocytes count in patients with sickle cell anaemia.

MATERIALS AND METHODS

A comparative cross-sectional study of 40 sickle cell anaemia patients in steady state (asymptomatic for at least 4 weeks) attending haematology clinic and 40 age and sex-matched healthy HbA control were recruited into the study. Both HbS patients and the controls were HIV negative. The blood samples obtained were analyzed for CD4+ T cell by Flow cytometry.

RESULTS

The study found that there was no significant difference in the number of CD4+ T lymphocyte count between individuals with sickle cell anaemia and HbA (1016 ± 513 cells/μL vs 920 ± 364cells/μL).

CONCLUSION

It is recommended that the functionality of CD4+ T lymphocyte should be considered rather than the number in further attempt to elucidate the cellular immune dysfunction in patients with sickle cell anaemia.

Reference ranges of lymphocyte subsets in healthy adults and adolescents with special mention of T cell maturation subsets in adults of South Florida

BACKGROUND

Analysis of peripheral blood lymphocyte subsets has become an essential tool in the evaluation of outcome of diagnostic and research related questions in immunological and pathological conditions. Periodic evaluation and establishment of normal lymphocyte reference ranges are required in clinical and research settings of various immunodeficiency disorders for evaluation of the significance of observations. It is also important that age and gender specific lymphocyte subset reference ranges should be locally established for meaningful comparison and accurate result interpretation as age plays a significant role in the development of immune system.

METHODS

We performed dual platform flow cytometry to determine reference ranges for lymphocyte subsets (CD3, CD4, CD8, CD19 [B cells] and CD16+CD56+ [Natural Killer - NK cells]) in 50 adolescents (age range: 12-18) and 100 adults (age range: 21-67) along with T cell maturation, activation and co-stimulatory molecules in healthy multiracial adult population of South Florida.

RESULTS

The lymphocyte reference ranges percentages [absolute counts - Abs, cells/μl] unadjusted for gender differences for adolescents are: CD3: 49-83 [939-2959]; CD4: 27-53 [467-1563]; CD8: 16-40 [259-1262]; CD19+ B cells: 8-31 [169-1297] and CD16+CD56+ NK cells: 3-30 [59-1178] and for adults are: CD3: 65-88 [983-3572]; CD4: 26-62 [491-2000]; CD8: 14-44 [314-2,087]; CD19+ B cells: 2-27 [64-800] and CD16+CD56+ NK cells: 2-27 [27-693]. The ranges for CD4:CD8 ratio for adolescents and adults are 0.7-2.6 and 0.6-4.4, respectively. Gender based analysis of relative percentages of lymphocyte subsets showed no significant differences between adult and adolescent males and females. The mean CD4:CD8 ratio was significantly higher in adult females than males (P=0.04) and in adolescents this difference was not significant between genders. The mean CD3 and CD4 T cell percentages were higher and CD19 cell percentages were lower in adults compared to adolescents (P<0.0001). Absolute lymphocyte counts showed a positive correlation with the absolute counts of CD3+, CD4+, CD8+, CD19+, CD16+CD56+, CD45RO+ and CD45RA+ cells (all correlations with P<0.0001 except CD45RO [P=0.01] and CD45RA [P=0.03]).

CONCLUSION

The reference values of peripheral blood lymphocyte subsets were analyzed in healthy adolescent and adult population of South Florida. This study indicates the need for periodic evaluation and establishment of lymphocyte reference ranges for patient population served based on gender and age since these could influence immune status and treatment outcome.

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.

Reference ranges for lymphocyte subsets among healthy Hong Kong Chinese adults by single-platform flow cytometry

Race, age, sex, and environmental conditions have significant impacts on lymphocyte subset values. It is important to establish the local reference ranges from healthy and non-HIV-positive adults in the local population for clinical decision making. In this study, the reference ranges for lymphocyte subsets among Chinese adults were established by analysis by single-platform flow cytometry of the lymphocyte compositions of 273 healthy adult blood donors between 17 and 59 years of age. The 95% reference ranges for CD3(+) T cells, CD3(+) CD4(+) T helper cells, and CD3(+) CD8(+) T suppressor cells are 723 to 2,271 cells/μl, 396 to 1,309 cells/μl, and 224 to 1,014 cells/μl, respectively. The 95% reference ranges for CD19(+) B cells and CD56(+) NK cells are 118 to 645 cells/μl and 61 to 607 cells/μl, respectively. Significant gender and age differences in the lymphocyte subsets have been demonstrated. Our results have also shown that the T-lymphocyte compositions in Hong Kong Chinese were comparable to those of other Asian populations but were different from those of Caucasians.

CD4 Count Pattern and Demographic Distribution of Treatment-Naïve HIV Patients in Lagos, Nigeria

Background. CD4 count measures the degree of immunosuppression in HIV-positive patients. It is also used in deciding when to commence therapy, in staging the disease, and in determining treatment failure. Using the CD4 count, this study aimed at determining the percentage of HIV-positives who require antiretroviral therapy at enrollment in an HIV treatment and care centre. Methods. The Baseline CD4 count, age and gender of 4,042 HAART-naïve patients, who registered between December 2006 and June 2010, at Lagos State University Teaching Hospital, Ikeja, were retrospectively studied. Data were analyzed using SPSS version 16.0 (Statistical Package for Social Sciences, Inc., Chicago, Ill). Results. Patients consisted of 2507 (62%) female and 1535 (38%) males. The mean age of males was 37.73 ± 9.48 years and that of females 35.01 ± 9.34 years. Overall, the mean CD4 count was of 298.76 ± 246.93  cells/mm³. The mean CD4 count of males was 268.05 ± 230.44  cells/mm³ and that of females 317.55 ± 254.72 cells/mm³. A total of 72.3% males, 64.3% females and 67.4% overall registered patients had CD4 count <350 cells/mm³, while only 15.1% males , 20.3% females, and 18.3% overall registered patients had CD4 count >500 cells/mm³ at registration. Conclusion. Females account for more than half of registered patients in HIV clinic and have a relatively higher CD4 count than males. About three-quarter of HIV positives require antiretroviral therapy at registration.

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.

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.

CD4+ T lymphocyte reference values of immunocompetent subjects in an African university

CD4(+) T cells play critical roles in the immune system and, being primary targets of HIV infection, they are used to measure disease progression and response to combination antiretroviral therapy (cART), alongside other parameters, in HIV/AIDS patients. The aim of this study was to determine the reference values of CD4(+) T cells in a student population that was HIV, hepatitis B virus (HBV) and hepatitis C virus (HCV) negative. After ethical clearance and informed consent, 500 subjects (mean age = 26 years) were recruited, of whom 56 (11.2%) had HIV, HBV or HCV and were excluded. Blood samples were collected from the remaining 444 subjects into vacutainer tubes and analysed using the BD FACScount cytometer according to the manufacturer's instructions. Of the 444 subjects, 266 (59.9%) were male and 178 (40.1%) were female. The mean (± standard deviation) CD4(+) T cell count was 987 cells/µL (± 336). The mean counts among males and females were 957 cells/µL (± 306) and 991 cells/µL (± 340), respectively. Values of CD4(+) T cells ranged from 651 cells/µL to 1705 cells/µL. Subjects with higher CD4(+) T Cells were more likely to be female than male. There was no direct correlation between CD4(+) T cell values and age of the participants. Our findings offer the first insight into the CD4(+) T cell reference values of a Nigerian student population and provide useful data that will guide future cART decisions and other immune-based therapies.

One percent tenofovir applied topically to humanized BLT mice and used according to the CAPRISA 004 experimental design demonstrates partial protection from vaginal HIV infection, validating the BLT model for evaluation of new microbicide candidates

Recent iPrEx clinical trial results provided evidence that systemic preexposure prophylaxis (PrEP) with emtricitabine (FTC) and tenofovir disoproxil fumarate (TDF) can partially prevent rectal HIV transmission in humans. Similarly, we have previously demonstrated that systemic administration of the same FTC-TDF combination efficiently prevented rectal transmission in humanized bone marrow/liver/thymus (BLT) mice. The CAPRISA 004 trial recently demonstrated that topical application of the tenofovir could partially prevent vaginal HIV-1 transmission in humans. To further validate the usefulness of the BLT mouse model for testing HIV prevention strategies, we evaluated the topical administration of tenofovir as used in CAPRISA 004 to prevent vaginal HIV transmission in BLT mice. Our results demonstrate that vaginally administered 1% tenofovir significantly reduced HIV transmission in BLT mice (P = 0.002). Together with the results obtained after systemic antiretroviral PrEP, these topical inhibitor data serve to validate the use of humanized BLT mice to evaluate both systemic and topical inhibitors of HIV transmission. Based on these observations, we tested six additional microbicide candidates for their ability to prevent vaginal HIV transmission: a C-peptide fusion inhibitor (C52L), a membrane-disrupting amphipathic peptide inhibitor (C5A), a trimeric d-peptide fusion inhibitor (PIE12-Trimer), a combination of reverse transcriptase inhibitors (FTC-TDF), a thioester zinc finger inhibitor (TC247), and a small-molecule Rac inhibitor (NSC23766). No protection was seen with the Rac inhibitor NSC23766. The thioester compound TC247 offered partial protection. Significant protection was afforded by FTC-TDF, and complete protection was offered by three different peptide inhibitors tested. Our results demonstrate that these effective topical inhibitors have excellent potential to prevent vaginal HIV transmission in humans.

Hematologic Abnormalities in Treatment-naïve HIV Patients

Objectives

Hematologic abnormalities, indicated by a deranged full blood count, are common manifestations and important prognostic tools for human immunodeficiency virus (HIV) infection and AIDS. This study aimed to determine the prevalence of cytopenia and its relationship to the degree of immunosupression in HIV treatment-naïve patients.

Methods

This was a cross-sectional study of treatment-naïve HIV-infected clients who enrolled at the HIV clinic of Lagos State University Teaching Hospital (LASUTH) between December 2009 and June 2010. Participants had samples taken for full blood count and CD4 counts, which are free routine pre-requisite and pre-treatment evaluations done for all registered HIV patients at LASUTH. They were asked to fill the structured questionnaires to obtain demographic data, with assistance if necessary.

Results

A total of 205 cases were reviewed: 24.2% had anemia (PCV < 30%), 26.8% had leucopenia (white blood cell <4,000/L) and 16.1% had thrombocytopenia (platelet count <150,000/L) at enrollment. The degree of cytopenia was directly related to the degree of immunosupression.

Conclusion

About one-fifth of HIV treatment-naïve patients were cytopenic at enrollment and the degree of cytopenia was directly related to the degree of immunosupression. It is necessary to investigate various causes of cytopenia in these patients so as to administer a specific intervention.