Early entry and widespread cellular involvement of HIV-1 DNA in brains of HIV-1 positive asymptomatic individuals

There is overwhelming evidence that invasion of the central nervous system (CNS) by HIV-1 takes place at an early stage of the infection. It has been demonstrated that HIV-1 DNA is present in brains of asymptomatic individual s. Evidence of immune activation and increased expression of cytokines sugg ested that neuropathological changes and neuronal and axonal damage could b e the effect of the presence of the virus. The purpose of the study is to a scertain whether target cells for HIV-1 in brain of patients at early stage of the infection are the same as those found in AIDS sufferers or if the d istribution seen in AIDS patients results from the late spreading of the in fection from cells considered traditionally the reservoir of the virus, i.e . microglial cells. Eighteen brains, all HN-I DNA positive, as shown by nes ted polymerase chain reaction (PCR), were selected among the group of HIV-I positive asymptomatic cases. In 6 of them, HIV-1 DNA was detected by PCR i n situ. Positive cells included astrocytes and endothelial cells, in additi on to microglial cells. We conclude that astrocytes and endothelial cells a re already infected at an early (asymptomatic) stage of the infection and s uggest that they might contribute to the damage of the CNS.