Immunoglobulin G subclasses in Crohn's disease with and without bowel resection.

Increased immunoglobulin G2 [IgG2] in Crohn's disease in contrast with increased IgG1 in ulcerative colitis was reported in literature data. The aim of our study has been focused on serum IgG subclasses in Crohn's disease with resected bowel (11 patients) and without previous surgery for Crohn's disease (12 patients). All patients were in active stage of the disease on total parenteral nutrition. Serum IgG subclasses were estimated by means of radial immunodiffusion. There was no significant differences between in IgG subclasses in Crohn's disease with and without bowel resection. IgG2 over 4.5 g/l was found only in 2/12 with resected bowel and 1/11 without previous surgery for Crohn's disease. Surprisingly, IgG1/IgG2 ratio below 1.5 was found only in 5/23 persons. In 3/23 patients IgG1 was over 10.5 g/l although there was no doubt about the diagnosis of Crohn's disease. IgG subclasses failed to help in confirmation of the diagnosis of Crohn's disease. Serum IgG subclasses alterations probably are not influenced by bowel resection and/or nutritional status.