CD68 and dementia: Thus, the most unique observation of our studies is that although parallel distributional trend of cellular infiltration of CD8+ T cells and CD68+ macrophages was seen in both HIV non-dementia and HAD patients (Fig.4a and 4d, b and 4e), the trend of cellular infiltration of CD8+ T cells and CD68+ macrophages following P24 staining was unique to HAD patients.