ACTIVATION OF MICROGLIA IN HIV-1-INFECTED BRAINS IS NOT DEPENDENT ON THE PRESENCE OF HIV-1 ANTIGENS

THE activation pattern of microglia in the cerebral cortex of AIDS pat ients with the neuropathological diagnosis of HIV-1 encephalitis was i nvestigated by immunohistochemistry and morphometry. The number of act ivated microglial cells in the grey and white matter of five cortical regions was determined. In the grey and white matter of all cortical r egions a significant increase in the number of microglial cells was de monstrated in HIV-1 infected brains. Moreover, the activation of micro glia was not correlated with the presence of HIV-1 antigen in the brai n region. The data show a significantly increased number of microglia in HIV-1 infected brains. These activated microglial cells could, amon g others, be those cells producing cytotoxic factors which, in turn, c ause brain damage.