부산대학교 도서관

Expression of the γ/δ T cell receptor (TCR) on CD3+ intraepithelial lymphocytes (IELs) was studied by two-colour immunofluorescence in duodenal tissue sections from healthy (n = 6) or infection-prone (n=7) subjects with selective IgA deficiency (IgAD), and subjects (n = 4) with combined IgAD and IgG subclass deficiency. TCRγ/δ+ IEL proportions in selective IgAD subjects (median 6.3%, range 1.0-41%.) and in those with combined deficiency (median 4.5%, range 1.2-33%) were well within the range (0.3-38%) for histologically normal controls (n=11), but the healthy IgAD subgroup tended to show raised TCRγ/δ+ IEL proportions (median 13.6%) compared with the other two subgroups. Also the number of TCRγ/δ+ IELs per intestinal length unit was relatively high (median 13.9/mm) in the healthy IgAD subjects, and significantly raised (P<0.03) compared with controls (median .12 'mm). Paired staining revealed that most TCRγ/δ+ IELs in both selective IgAD (98%) and combined deficiency (99%) were CD8-, and a large fraction (median 84% and 63%, respectively) expressed the Vδ1/Jδl-encoded epitope. The total number of CD3+ IELs (mostly CD8+) was similar to controls. IgAD subjects, and especially the healthy subgroup, had significantly increased serum concentrations of soluble CD8 (P<0.0002). neopterin (P<0.005), and β2-microglobulin (P<0.007), which was similar to our previous observations in common variable immunodeficiency, and probably reflected stimulation of cell-mediated immunity. In addition, the increased TCRγ/δ+ IELs might reflect a component of compensatory surface protection in the healthy IgAD subgroup. [ABSTRACT FROM AUTHOR]