MONOCYTE PHAGOLYSOSOMAL FUSION IN CHILDREN BORN TO HUMAN IMMUNODEFICIENCY VIRUS-INFECTED MOTHERS

Background. Previously we demonstrated that monocyte phagolysosomal fu sion is impaired in chronic HIV infection in adult patients. Methods. We studied the phagolysosomal fusion of peripheral blood monocytes fro m 45 children vertically infected with HIV, 38 noninfected infants bor n to HIV-positive mothers and 14 children born to HIV-seronegative wom en, by a cytomorphologic method in which acridine orange is used as a fusion marker. Results. The mean percentages of phagolysosomal fusion +/- SD were 42 +/- 16.1 for HIV-positive children, 55.3 +/- 15.5 for H IV-negative infants born to HIV-infected mothers and 58.2 +/- 12.7 for normal controls. Monocyte phagolysosomal fusion of HIV-infected child ren was significantly decreased in comparison to noninfected and norma l infants (P < 0.001), while there was no difference between the two l atter groups. Phagolysosomal fusion impairment in HIV-infected infants inversely correlated with age (r = -0.4527; P < 0.002) and directly c orrelated with CD4+ T cell counts (r = 0.393; P = 0.03). Moreover, pha golysosomal fusion strongly correlated with clinical manifestations; t his function was significantly impaired in moderately and severely sym ptomatic HIV-infected children with respect to those who remained asym ptomatic or mildly symptomatic (P < 0.05). Conclusions. Our results su ggest that monocyte function in HIV-infected children progressively de teriorates, closely related to the severity of the clinical symptoms.