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

• Published in: Journal of allergy and clinical immunology Vol. 125; no. 1; pp. 203 - 208
• Main Authors: Mandala, Wilson L., PhD, MacLennan, Jenny M., MRCP, MRCPCH, Gondwe, Esther N., BSc, Ward, Steven A., PhD, Molyneux, Malcolm E., FMedSci, MacLennan, Calman A., DPhil, FRCPath
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 2010; Elsevier; Elsevier Limited; Mosby
• Subjects: Acquired immune deficiency syndrome; Adolescent; Adult; Africa; Aged; Aged, 80 and over; AIDS; Allergy and Immunology; B-Lymphocyte Subsets - immunology; Biological and medical sciences; CD4 Lymphocyte Count; Child; Child, Preschool; Female; Flow Cytometry; Fundamental and applied biological sciences. Psychology; Fundamental immunology; HIV; HIV Infections - immunology; Human immunodeficiency virus; Human viral diseases; Humans; Immune Deficiencies, Infection, and Systemic Immune Disorders; Immune system; Immunodeficiencies; Immunodeficiencies. Immunoglobulinopathies; Immunopathology; Immunophenotyping; Infant; Infant, Newborn; Infectious diseases; Lymphocyte subsets; Lymphocyte Subsets - immunology; Lymphocytes; Malawi; Male; Medical sciences; Middle Aged; Sarcoidosis. Granulomatous diseases of unproved etiology. Connective tissue diseases. Elastic tissue diseases. Vasculitis; T-Lymphocyte Subsets - immunology; Viral diseases; Viral diseases of the lymphoid tissue and the blood. Aids; Young Adult; Malawi; Africa; ART; World Health Organization; Africa; AIDS; Lymphocyte subsets; Antiretroviral therapy; HIV; immunophenotyping; CD4 lymphocyte count; Natural killer; flow cytometry; NK; WHO; Flow cytometry; Immunopathology; immnnophenotyping; Retroviridae; Immune deficiency; Lentivirus; Cell subpopulation; Infection; Virus; Numeration; Immunology; Viral disease; Human immunodeficiency virus; Lymphocyte
• ISSN: 0091-6749; 1097-6825
• DOI: 10.1016/j.jaci.2009.10.010

Background CD4+ T lymphocyte measurements are the most important indicator of mortality in HIV-infected individuals in resource-limited settings. There is currently a lack of comprehensive immunophenotyping data from African populations to guide the immunologic assessment of HIV infection. Objective To quantify variation in absolute and relative lymphocyte subsets with age in healthy Malawians. Methods Lymphocyte subsets in peripheral blood of 539 healthy HIV-uninfected Malawians stratified by age were enumerated by flow cytometry. Results B and T–lymphocyte and T-lymphocyte subset absolute concentrations peaked in early childhood then decreased to adult levels, whereas lymphocyte subset proportions demonstrated much less variation with age. Adult lymphocyte subsets were similar to those in developed countries. In contrast, high B-lymphocyte and CD8+ T-lymphocyte levels among children under 2 years, relative to those in developed countries, resulted in low CD4+ T-lymphocyte percentages that varied little between 0 and 5 years (35% to 39%). The CD4+ T-lymphocyte percentages in 35% of healthy children under 1 year and 18% of children age 1 to 3 years were below the World Health Organization threshold defining immunodeficiency in HIV-infected children in resource-limited settings. Thirteen percent of healthy children under 18 months old had a CD4:CD8T-lymphocyte ratio <1.0, which is commonly associated with HIV infection. All immunologic parameters except absolute natural killer lymphocyte concentration varied significantly with age, and percentage and overall absolute CD4+ T-lymphocyte counts were higher in females than males. Conclusion Although lymphocyte subsets in Malawian adults are similar to those from developed countries, CD4+ T-lymphocyte percentages in young children are comparatively low. These findings need to be considered when assessing the severity of HIV-related immunodeficiency in African children under 3 years.