Autoimmunity in ulcerative colitis (UC): a predominant colonic mucosal B cell response against human tropomyosin isoform 5.
We set out to examine if the IgG-producing cells in the colonic mucosa in UC are committed to tropomyosin isoform 5 (hTM5), a putative autoantigen in UC. Lamina propria mononuclear cells (LPMC) were isolated from colonoscopic biopsy specimens from recto-sigmoid and proximal colon. Twenty-three patients with UC, eight with Crohn's colitis (CC), and 10 non-inflammatory bowel disease (non-IBD) controls were included. The ELISPOT assays were used to quantify lamina propria B cells producing total immunoglobulin (IgA, IgG, IgM), IgG, IgA, as well as IgG against hTM5 isoform. The median value of percentage of total IgG-producing lymphocytes was similar in UC (12%) and CC (11%), but was significantly (P < 0.0002) higher than non-IBD controls (6%). However, in UC, but not in CC and non-IBD, a large number of lamina propria B cells produced IgG against hTM5 (median values: UC 42%, CC 2.5%, non-IBD 0%). This difference in UC when compared with CC and non-IBD was highly significant (P < 0.00001). Twenty-one of 23 (91%) patients with UC had percentage of anti-hTM5 IgG-producing immunocytes more than 2 s. d. above the mean for non-UC patients. In UC but not in CC and non-IBD controls, the increased number of IgG-producing cells are largely committed to produce IgG against hTM5-related epitope(s).
Onuma
E K
EK
Division of Gastroenterology and Hepatology, Department of Medicine, UMDNJ-Robert Wood Johnson Medical School, New Brunswick, NJ 08903, USA.
Amenta
P S
PS
Ramaswamy
K
K
Lin
J J
JJ
Das
K M
KM
D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000096:biosynthesis; D015551:Autoimmunity; D001402:B-Lymphocytes / Q000276:immunology*; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000276:immunology* / Q000473:pathology; D003106:Colon / Q000276:immunology / Q000473:pathology; D000939:Epitopes; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D007413:Intestinal Mucosa / Q000276:immunology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D020033:Protein Isoforms / Q000276:immunology; D014335:Tropomyosin / Q000276:immunology*
D001323:Autoantibodies; D000939:Epitopes; D007074:Immunoglobulin G; D020033:Protein Isoforms; C498783:TPM3 protein, human; D014335:Tropomyosin