Role of the low af fi nity IgE re cep tor (CD23) on the IgE res pon se against Asca ris lum bri coi des in Wa rao Ame rin dian chil dren from Ve ne zue la.

Abstract

Abstract. The ob jec tive of this study was to in ves ti gate the im mune mech a nisms against gas tro in tes ti nal helminths in volved in the pro duc tion of IgE, par tic u larly the role of the low af fin ity IgE re cep tor (CD23) in Am er in - dian Warao chil dren from the Orinoco Delta, Ven e zuela. We stud ied a group of un se lected (n = 159) Warao school chil dren with high prev a lence and in - ten sity of helminthic in fec tion and a sim i lar non- par a sit ized (n = 70) con trol group of a “creole” com mu nity also lo cated at the Delta of the Orinoco. The lev els of to tal and spe cific anti-Ascaris IgE, de ter mined by ELISA, were ex - tremely higher in the Warao chil dren (p < 0.001) com pared to the con trol group. How ever, only a re duced group of these chil dren were able to de velop a clin i cally sig nif i cant (> 0.7 PRU/mL) IgE re sponse against A lumbricoides an - ti gens. Cir cu lat ing T helper cells (CD3+CD4+), ac ti vated B (CD20+, CD20+CD21+) lym pho cytes and the ex pres sion of the low af fin ity re cep tor for IgE (CD23), de ter mined by flow cytometry, were sig nif i cantly (p < 0.001) el e vated in the Warao chil dren, par tic u larly in those with an en hanced ca pac - ity to mount ef fi cient spe cific anti Ascaris IgE re sponses. Strong cor re la tions (p < 0.001) were found be tween the num ber of cir cu lat ing CD20+CD23+ cells and the level of to tal and anti-A lumbricoides IgE. Also, a sig nif i cant (p < 0.005) cor re la tion be tween CD20+CD23+ and CD4+ cir cu lat ing cells was ob served. We con clude that A lumbricoides an ti gens may stim u late the pro duc tion of to - tal and spe cific IgE through a CD23 de pend ent path way. How ever the dif fer - ent en vi ron men tal and ge net ics fac tors in volved in the ca pac ity to de velop ef - fi cient spe cific re sponses among the Warao pop u la tion still need to be elu ci - dated.