Erosive polyarthritis and Crohn's disease. A case with HLA DRB1 determination.

The authors report the case of a 49-year-old woman with an asymmetrical, seronegative and peripheral polyarthritis with erosions, who subsequently developed Crohn's disease. She was diagnosed as having an erosive Crohn polyarthritis as no evidence of rheumatoid arthritis was found. However, the patient was homozygote for DR4 and the HLA DRB1 oligotyping was 0401/0404. This corresponds to two susceptibility alleles for rheumatoid arthritis responsible for the severity of this disease. Erosive polyarthritis is rarely encountered in inflammatory bowel diseases. The underlying mechanism of the erosions in these conditions is unknown but granulomatous synovitis with contiguous erosive bone changes has been reported. HLA DR has not been previously reported in erosive Crohn polyarthritis. The homozygosity for DR4 with DRB1*0401/0404 subtypes suggests that DR4 could contribute to the erosive course in this patient. This question is of interest, and HLA DR must be further studied in inflammatory bowel diseases with erosive arthritic manifestations.