IMMUNOHISTOLOGICAL CHARACTERIZATION OF THE GUT-ASSOCIATED LYMPHOID-TISSUE IN PATIENTS WITH AIDS

Lamina propria mononuclear cells in duodenal and colonic biopsies of AIDS patients and controls were immunohistologically studied for T-cells (CD3), IgA1+, IgA2+, IgM+, IgG2+, IgG4+ and J-chain-positive cells. In AIDS patients, there was a decrease of IgA1+ (p = 0,0009), IgA2+ (P = 0,011), IgM+ (p = 0,018), IgG4+ (p = 0,0002) cells in the duodenum. In the colonic biopsies, IgA2+ (p = 0,0001) and IgG2+ (p = 0,0372) cells were also decreased, whereas the IgM+ cells were increased (p = 0,0023). Relative numbers of J-chain-expressing cells of the small and large intestine were not different from controls (p = 0,373; p = 0,0618). The number of T-cells was reduced in duodenal and colonic biopsies (p = 0,0002; p = 0,0030). The presented results are compatible with the assumption of a functional B-cell defect of the intestinal immune system. The decrease of Ig-producing cells in the intestine contrasts with the increased levels of serum Ig in AIDS patients, indicating that the GALT is a particular compartment of the immune system.