EXPRESSION OF A NOVEL AUTOANTIBODY DEFINED BY THE V(H)3-15 GENE IN INFLAMMATORY BOWEL-DISEASE AND CAMPYLOBACTER-JEJUNI ENTEROCOLITIS

This study newly introduces anti-V-H mAbs to assess the role of clonal B cell activity in inflammatory bowel disease. Immunohistochemistry o f colonic biopsies in ulcerative colitis (UC) and Crohn's disease (CD) , but not unaffected individuals, demonstrated uniform staining of int ravascular erythrocytes with BK2, a monoclonal specific for the V(H)3- 15 Ig heavy chain gene product. Staining was caused by erythrocytes op sinized in vivo by anti-erythrocyte Abs present in patient sera and by using the V(H)3-15 gene product. The erythrocyte Ag was identified by immunoprecipitation as 22- and 28-kDa membrane proteins. A direct flo w cytometric assay was developed to measure this serum autoantibody an d was tested in 101 individuals with UC, CD, other acute or chronic co litis, and healthy controls. Compared with normal subjects, BK2(+) ant i-erythrocyte Abs were elevated in most sera from patients with CD and UC (including postcolectomy). BK2(+) anti-erythrocyte Abs also were e levated in 10 of 38 noninflammatory bower disease patients, all of who m had Campylobacter jejuni enterocolitis. These findings suggest that a common immunopathogenetic factor, manifested by V(H)3-15 B cell acti vation may be shared in UC, CD, and Campylobacter jejuni enterocolitis .