Establishment of Reference Values of CD4 and CD8 Lymphocyte Subsets in Healthy Nigerian Adults

Abstract

A total of 2,570 apparently healthy human immunodeficiency virus-negative adults from the six geopolitical zones in the country were enrolled in our study in 2006. The samples were assayed using the Cyflow technique. Data were analyzed using the Statistical Package for Social Scientists (SPSS). The majority (64%) of the participants had CD4 counts within the range of 501 to 1,000 cells/l. The reference range for CD4 was 365 to 1,571 cells/l, while the reference range for CD8 was 145 to 884 cells/l.In Nigeria, although country-specific reference ranges for some hematological measures have been determined (3,5,6), national data for CD4 reference values are still not available. Prior to a few recent monocenter studies carried out among defined populations of healthy Nigerians (2, 13), CD4 reference range values from literature based on studies in western countries were largely employed for clinical decision making.However, as the access to treatment increased in Nigeria, it became critically necessary to determine on a national level the reference values for CD4 cell counts and the factors that may affect it. This was necessary to inform the clinicians of the required minimal range for the initiation of antiretroviral therapy, and also for accurate monitoring of responses to therapy and other treatment outcomes.The national study reported in this document was a multicenter study conducted among healthy human immunodeficiency virus (HIV)-negative adult Nigerians, in eight sites across the six geopolitical zones of the country. Therefore, the objective of this study was to establish the normal reference values of CD4 and CD8, as well as CD4/CD8 lymphocyte ratios, indigenous to Nigeria.This project was carried out as a cross-sectional study among apparently healthy Nigerians aged 18 years and older who tested HIV negative at voluntary counseling and testing site sites. Exclusion criteria included pregnancy, sickle cell anemia, or clinical illness.A 5-ml sample of blood was collected from each participant by venipuncture into a Vacutainer EDTA bottle. These samples were retested using the Genie II kit (Bio-Rad), which is a rapid HIV serology test kit. Only samples that were confirmed negative were assayed for CD4 and CD8 cell counts concurrently using the Cyflow technique, with an instrument known as the Cyflow counter (Partec). This instrument is for counting and analyzing particles and cells. The first step in the measurement of cells is staining with a fluorescent dye. The fluorescent molecules are taken up by the cells. The cells are individually illuminated by light of a defined wavelength. The light activates the fluorescent molecules so that they emit light of a characteristic color (wavelength). This fluorescent light is filtered out, and its intensity is measured by a ploidy analyzer for each single cell. The fluorescence light intensity emitted by a labeled cell is proportional to its CD4 or CD8 content. For cell counting or concentration determination, the sample volume detector measures exactly 0.2 ml of th...

Reference Ranges for Lymphocyte Subsets among Healthy Hong Kong Chinese Adults by Single-Platform Flow Cytometry

“…Sex influences on lymphocyte subset constitution have also been addressed in various ethnic groups (5,9,10,15,17,18). Our study also has a higher absolute count and percentage of CD3 ϩ T cells in females compared with males, while the absolute count and percentage of CD56 ϩ NK cells are higher in males (P Ͻ 0.05).…”

Estimating the time period between infection and diagnosis based on CD4+ counts at first diagnosis among HIV-1 antiretroviral naïve patients in Nigeria

“…The CD4 + count level at time of diagnosis was used to provide an indication of the time delay between HIV infection and diagnosis among Nigerians as a function of normal CD4 + decay per calendar year in drug naïve individuals. The normal reference values of CD4 + counts in healthy Nigerians have been established to range from 365-1571 cells/L [18]. This reference value is supported by another study of healthy Nigerians that showed the specific mean reference CD4 + among men to be 717 cells/L and 869 cells/L among non-pregnant females [19].…”

Assessment of CD4 T Lymphocyte Cell Levels among Hepatitis B, C and E Viruses Negative Individuals in Ibadan, southwestern Nigeria

“…This is consistent with the NRVs [18], and in agreement with reports from previous studies [5,21].Specifically, among different age groups we recorded higher CD4 T lymphocyte values than the NRVs in this study. This is also consistent with Adoga et al, [21], who reported higher than the NRVs.…”

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