title: An inexpensive, simple, and manual method of CD4 T-cell quantitation in HIV-infected individuals for use in developing countries.
abstract: CD4+ T lymphocytes are currently the most common surrogate marker indicating immune status and disease progression with HIV infection. The cost of monitoring disease progression and response to therapy is still prohibitively expensive. Flow cytometry is the gold standard for the estimation of CD4+, but the high initial investment for this technology and expensive reagents makes it unaffordable for developing countries like India. We evaluated the Coulter cytosphere assay for quantifying CD4+ T lymphocytes in comparison with the standard method, flow cytometry, in 122 HIV-infected individuals. The correlation coefficient of the cytosphere assay compared with that of flow cytometry for CD4+ T lymphocytes was 0.97 (P< 0.0001), with a confidence interval of 0.95 to 0.98. The sensitivity, specificity, positive predictive value, and negative predictive value of the cytosphere assay in enumerating absolute CD4+ T-lymphocyte counts of less than 200/microL were 94.9%, 96.4%, 92.5%, and 97.6%, respectively. This is a simple inexpensive method and has a strong correlation with flow cytometry. Hence, the cytosphere assay can be an alternate to flow cytometry for the estimation of CD4+ T-lymphocyte counts, especially in resource-poor settings of developing countries, for monitoring HIV progression and response to therapy.
authors.affiliation: YRG Centre for AIDS Research and Education, Voluntary Health Services, Taramani, Chennai, India. bala@yrgcare.org
authors.forename: Pachamuthu
authors.initials: P
authors.lastname: Balakrishnan
authors.forename: Mandy
authors.initials: M
authors.lastname: Dunne
authors.forename: Nagalingeshwaran
authors.initials: N
authors.lastname: Kumarasamy
authors.forename: Suzanne
authors.initials: S
authors.lastname: Crowe
authors.forename: Gangadharan
authors.initials: G
authors.lastname: Subbulakshmi
authors.forename: Aylur K
authors.initials: AK
authors.lastname: Ganesh
authors.forename: Anitha J
authors.initials: AJ
authors.lastname: Cecelia
authors.forename: Patricia
authors.initials: P
authors.lastname: Roth
authors.forename: Kenneth H
authors.initials: KH
authors.lastname: Mayer
authors.forename: Sandras P
authors.initials: SP
authors.lastname: Thyagarajan
authors.forename: Suniti
authors.initials: S
authors.lastname: Solomon
mesh_terms: D018791:CD4 Lymphocyte Count / Q000191:economics / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D003365:Costs and Cost Analysis; D003906:Developing Countries; D005260:Female; D005434:Flow Cytometry / Q000592:standards / Q000706:statistics & numerical data; D015658:HIV Infections / Q000276:immunology*; D006801:Humans; D007194:India; D008297:Male