EXPRESSION OF CD23 ANTIGEN AND ITS LIGANDS IN CHILDREN WITH INTRINSICAND EXTRINSIC-ASTHMA

The role of the low-affinity IgE receptor CD23 in immune reactions has been further emphasized by recent discoveries of novel surface ligand s for CD23: CD21, CD11b, and CD11c. We previously observed the differe nce between the expression of CD23 and CD21 antigens in children suffe ring from extrinsic asthma when compared to healthy controls. In the p resent study, we investigated the expression of CD23 and its ligand CD 21 on CD20(+) B cells in 44 asthmatic children (23 allergic and 21 non allergic) using three-color immunofluorescence analysis. In addition, the expression of two other ligands for CD23, CD11b, and CD11c, on T c ells (CD3(+)), a subpopulation of T cells (CD4(+) and CD8(+)), natural killer cells (CD56(+)), and monocytes (CD14(+)) was tested by two-col or immunofluorescence analysis in 12 allergic and 14 nonallergic child ren. We found that children with extrinsic asthma had higher levels of CD23(+) B cells than those with intrinsic asthma. No difference was o bserved in the percentage of either CD23(+)CD21(+) or CD23(-) CD21(+) B cells. The CD11b antigen was expressed on each tested population, bu t only on CD4(+) cells was CD11b significantly increased in children w ith extrinsic asthma. CD11c was expressed mainly on monocytes, and no difference was observed between tested groups. The increased percentag e of CD11b antigen on CD4(+) T cells and the increased percentage of C D23 antigen on B cells in children with extrinsic asthma provide furth er evidence of the immunologic differences between intrinsic and extri nsic asthma.