Fate of oligodendrocytes in HIV-1 infection.

The brains of 22 HIV-1-infected cases and 11 controls, matched for age and sex, were studied with immunocytochemical reactions specific for oligodendrocytes, astrocytes, microglia and HIV-1. In HIV-1 infection, mild degrees of myelin damage were associated with an increase in oligodendrocyte numbers, a change that was reversed in the presence of severe damage. Severity of myelin damage correlated with the extent of astrocytic and microglial reactions expressed in a semi-quantitative manner. HIV-1 p24 antigen was detected in all cases with severe myelin damage and a smaller proportion of cases with lesser degrees of myelin damage. It is concluded that, in HIV-1 infection, oligodendrocytes undergo an initial reactive hyperplasia which may represent an attempt to repair myelin damage.