Asymptomatic simian immunodeficiency virus infection decreases blood CD4(+) T cells by accumulating recirculating lymphocytes in the lymphoid tissues.
Declining blood CD4(+) T-cell counts mark the progress of simian immunodeficiency virus (SIV) disease in macaques and model the consequences of untreated human immunodeficiency virus infection in humans. However, blood lymphocytes are only a fraction of the recirculating lymphocyte pool, and their numbers are affected by cell synthesis, cell depletion, and distribution among blood and lymphoid tissue compartments. Asymptomatic, SIV-infected macaques maintained constant and nearly normal numbers of recirculating lymphocytes despite the decline in CD4(+) T-cell counts. Substantial depletion was detected only when blood CD4(+) T-cell counts fell below 300/microliter. In asymptomatic animals, changes in CD4(+) T-cell distribution were more important than lymphocyte depletion for controlling the blood cell levels.
Schenkel
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AR
Department of Pathology and Laboratory Medicine and Wisconsin Regional Primate Research Center, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
Uno
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Pauza
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D000818:Animals; D018791:CD4 Lymphocyte Count; D016516:CD4-CD8 Ratio; D008198:Lymph Nodes / Q000473:pathology; D008221:Lymphoid Tissue / Q000473:pathology*; D008253:Macaca mulatta; D016097:Simian Acquired Immunodeficiency Syndrome / Q000276:immunology* / Q000473:pathology