Human immunodeficiency virus type 1 infection alters enzymatic and ultrastructural features of peripheral blood monocytes

INTRODUCTION: Human immunodeficiency virus-1 (HIV-1) infected monocytes are now believed to serve as a reservoir for HIV-1 infection, and to play a role in viral rebound phenomena in certain groups of patients who failed or stopped highly active antiretroviral therapy (HAART). Data characterizing the morphological changes of peripheral blood monocytes in HIV-1-infected individuals are limited. MATERIALS AND METHODS: In this study, we collected monocytes from 21 asymptomatic HIV-1-infected individuals with CD4 count more than 500 cells/mm(3) and healthy individuals. The monocytes ultrastructural morphologic changes and α-naphthyl butyrate esterase (ANBE) activity were compared between the two groups. RESULTS: In monocytes from patients infected with HIV-1, activity of α-naphthyl butyrate esterase (ANBE) was markedly increased compared with normal monocytes. In both light microscopic and ultrastructural studies, the cytoplasm of monocytes from HIV-1-infected patients contained a haphazard appearing network of thin fibrils. Cell surface expression of the activation marker HLA-DR molecule was upregulated. There were no discernible differences between the cell surface expression of CD4, CD14, and CD16 molecules comparing normal monocytes to those from HIV-1-infected patients. α-naphthyl butyrate esterase (ANBE) was markedly increased compared with normal monocytes. In both light microscopic and ultrastructural studies, the cytoplasm of monocytes from HIV-1-infected patients contained a haphazard appearing network of thin fibrils. Cell surface expression of the activation marker HLA-DR molecule was upregulated. There were no discernible differences between the cell surface expression of CD4, CD14, and CD16 molecules comparing normal monocytes to those from HIV-1-infected patients. CONCLUSIONS: Possibly, changes in the activity of ANBE along with a disrupted appearing cytoplasmic fibril network contribute to monocyte dysfunction in HIV-1-infected patients.