The presence of proteins (p17 and p24 core proteins, gp41 envelope protein) and mRNA (gag/pol and env gene segments) of human immunodeficiency virus type-1 (HIV-1) was analyzed on frozen tissue sections of lymph nodes from HIV-1 infected individuals. Thirty-one lymph nodes were categorized in the stages of follicle hyperplasia (n= 18), follicle degeneration (n= 5), and total depletion (n= 8). The follicle dendritic cells in germinal centers showed the presence of core proteins and, to a lesser extent, gp41. The staining patterns, being similar to those of immunoglobulins, suggested that they occur in the form of immune complexes. In addition there were solitary cells expressing viral protein, in particular gp41, and mRNA. The number of mRNA-positive cells was very low: about five positive cells were observed in a tissue section with about ten (hyperplastic) follicles. HIV-1-mRNA-positive cells were observed both in follicles and interfollicular areas and showed no differences between various stages. The extent and intensity of distinct HIV-1 proteins and HIV-1-mRNA gene segments in follicles were significantly correlated, as was their presence in interfollicular areas. No significant correlation was found between the presence of HIV-1 components in follicles and in interfollicular areas. This indicates that processes involving HIV-1 components occur in a segregated manner in both lymph node compartments. The presence of HIV-1 components did not correspond to any clinical classification (CDC criteria), nor to other histochemical characteristics. An exception was the correlation between gp41-positive cells and CD1-positive interdigitating cells in the interfollicular areas.