A prospective study of patients with spondyloarthropathy with special reference to HLA-B27 and to gut histology.

Ileocolonoscopy was performed on 357 patients meeting the European Spondylarthropathy Study Group criteria for spondyloarthropathy. HLA loci A, B and C were determined in all patients; HLA-B27 was detected in 196 and was absent in the 161 remaining patients. A number of clinical, laboratory and radiological variables were determined before ileocolonoscopy and compared between the HLA-B27+ and HLA-B27- patients. The HLA-B27+ patients were mainly men, with significantly more family members with spondyloarthropathies. Clinical evidence of tendinitis and uveitis was more frequently found in these patients. Like several authors, we found that these patients were more severely affected since they presented more severe radiological involvement of the sacroiliac joints. Syndesmophytes, bamboo spine and erosive joint lesions were more frequent in this group, the hip involvement being of the concentric type. In HLA-B27+ patients ankylosing spondylitis was more prevalent, while in the B27- patients enterogenic, urogenital or undifferentiated spondyloarthropathy was diagnosed. The HLA-B27- patients experienced more episodes of diarrhea, and Crohn-like inflammatory gut lesions were more frequently seen on ileocolonoscopy. In this group a number of patients probably had a form of subclinical Crohn's disease of which the locomotor symptoms were the only clinical expression.