Monoclonal Antibody-Defined β₂-Microglobulin-Positive Mononuclear Cells in Acquired Immune Deficiency Syndrome

In healthy heterosexuals, by means of a monoclonal antibody against β₂-microglobulin (β₂m) and fluorescence-activated cell sorter analyser (FACS analyser), we observed two populations of β₂⁺ mononuclear cells (MNC); a large population with high-intensity cells and a small population of relatively low-intensity cells. Because elevated β₂m levels have been shown in the sera of patients with acquired immune deficiency syndrome (AIDS), we examined the proportions of β₂m⁺ MNC in AIDS and AIDS-related complex (ARC). The proportions and numbers of high-fluorescence intensity β₂m⁺ MNC were significantly (P<0.05) decreased in AIDS and ARC when compared with those of asymptomatic homosexuals and healthy heterosexuals. The proportion and number of total β₂m⁺ MNC (both high- and low-intensity β₂m⁺) in ARC were comparable to those of control groups; however, the numbers of total β₂m⁺ MNC were significantly (P<0.01) reduced only in the AIDS group. This relative deficiency of highintensity β₂m⁺ MNC appears to be due to a shift from high-intensity β₂m⁺ to low-intensity β₂m⁺ MNC. A linear correlation was observed between the deficiency of high-intensity β₂m⁺ cells and T helper to T suppressor phenotype cell ratios.