To assess the relationship of poststreptococcal reactive arthritis (ReA) to other forms of ReA and rheumatic fever by comparing the frequency of HLA-B27 and DRB1 alleles in these diseases.
The diagnosis of poststreptococcal ReA was established in 25 children seen in a pediatric rheumatology clinic. HLA-B27 and DRB1 genotyping was performed in 18 of the white American patients. The DRB1 genotyping results were compared with those in 33 patients with rheumatic fever and 190 normal individuals.
HLA-B27 was positive in 3 of the 18 poststreptococcal ReA patients, a frequency not different from that found in normal individuals. Compared with normal controls, the frequency of the DRB1*01 allele was higher in poststreptococcal ReA patients (odds ratio [OR] 2.7, P=0.044), while DRB1*16 was increased in patients with rheumatic fever (OR 4.3, P=0.028).
The association of poststreptococcal ReA with HLA-DRB1*01, but not with HLA-B27, suggests that its pathogenesis may be more similar to that of rheumatic fever than to that of ReA associated with enteric pathogens.