DIFFUSE MICROGLIOSIS ASSOCIATED WITH CEREBRAL ATROPHY IN THE ACQUIRED-IMMUNODEFICIENCY-SYNDROME

The cause of cerebral atrophy in patients with acquired immunodeficien cy syndrome (AIDS) is obscure because human immunodeficiency virus typ e 1 (HIV-1)-related histopathological changes hardly correlate with ce rebral atrophy. In this study, brain ventricular expansion was compare d to the frontal lobe density of mononuclear and astroglial cells at a utopsy. Twenty-eight male patients with AIDS displaying varying degree s of atrophy were compared to 17 age-matched male control subjects wit hout AIDS or atrophy. An index of ventricular expansion was measured i n uniformly sliced, formalin-fixed brain specimens, and immunochemical ly marked cells in coronal sections of the left superior frontal gyrus (Brodmann area 8) were quantified by field counting and planimetry. I n the cortex, diffuse ferritin-stained microglia and glial fibrillary acidic protein-positive astrocytes were about twice as numerous in the patients with AIDS. Sixty-five percent (18/28) of the patients with A IDS had a microglial cell density greater than 2 standard deviations a bove the control mean. Microglial cell density was correlated positive ly with the severity of ventricular expansion (r = 0.71, p < 0.0001), while hypertrophied astroglial cells were very weakly related. In whit e matter, Ham-56-positive macrophages and glial fibrillary acidic prot ein-positive astrocytes were not meaningfully correlated with the inde x of ventricular expansion. Brain ventricular expansion and diffuse co rtical microgliosis are highly prevalent anomalies in patients with AI DS, and their interrelationship may be more important than previously recognized.