Decreased numbers of circulating plasmablasts and differences in IgA1‐plasmablast homing to skin in coeliac disease and dermatitis herpetiformis

Summary The two clinical phenotypes of gluten enteropathy, coeliac disease (CD) anddermatitis herpetiformis (DH), were characterized for numbers and homingprofiles of circulating final effector B cells, plasmablasts, identified as immu-noglobulin (Ig)-secreting cells (ISC). In CD, the numbers of ISC were ~50%lower than in DH or controls. ISC expressed peripheral lymph node homingreceptor(HR),L-selectin,lessfrequentlyinCD(54%)andDH(52%)patientsthan in controls (70%). The expression of gut mucosal HR, a 4 b 7 , was lessfrequentinCD(42%)thaninDH(65%)orcontrols(60%).InDH,butnotinCDorcontrols,ahigherproportionof IgA1-ISC(40%)thanIgA2-ISC(25%)expressed the skin HR, cutaneous lymphocyte-associated antigen. In glutenenteropathy circulating plasmablasts are more mature, but decreased innumber, and have distorted homing profiles. Differential IgA1-plasmablasthoming could be associated with the development of skin rash with IgA1-deposits in DH but not in CD. Keywords: adhesion molecules , Bcells , coeliac disease dermatitis herpetifor-