CLINICAL, SEROLOGIC, AND IMMUNOGENETIC FEATURES IN POLISH PATIENTS WITH IDIOPATHIC INFLAMMATORY MYOPATHIES

Objective. To determine the clinical, serologic, and immunogenetic cor relations in patients with idiopathic inflammatory myopathies (IIM), a nd to evaluate the useful grouping of some diseases for practical clin ical purposes. Methods. Patients with IIM were categorized according t o clinical presentation as compared with autoantibody specificity. Ser um samples from 84 patients were screened for myositis-specific autoan tibodies (MSAs) by indirect immunofluorescence and double immunodiffus ion. All sera were also studied by protein A-assisted immunoprecipitat ion. Genomic DNA was isolated from peripheral blood mononuclear cells, and HLA-DQA1 and DRB1 alleles were determined. The patients were seen and followed up for many years in the same center. Results. MSAs were present in 19% of patients. The most common MSAs were antisynthetases in 13% of patients (Jo-1 10.7%, PL-12 1.2%, add EJ 1.2%); associated with the antisynthetase syndrome. Anti-SRP was found in 1.2% of patien ts, associated with polymyositis, and anti-Mi-2 in 4.9%, found exclusi vely in patients with dermatomyositis. The most frequent MSA was PM-Sd in 23.8% of patients, associated with scleromyositis, and Ku was pres ent in 9.6% of patients with overlap syndromes. The alleles that were found at a significantly increased frequency were HLA-DRB10301 (59.4% ) and DQA10501 (71.6%), which are in linkage disequilibrium. DQA1*050 1 aas present in 85.75 of patients with antisynthetases, and in 100% o f patients with PM-ScI and Ku. Conclusion. The HLA-DRB10301; DQA1*050 1 haplotype was found to be significantly increased in this population overall and in those myositis patients with antisynthetase, anti-PM-S d, and anti-Ku antibodies. The results of this study confirm that IIM are heterogeneous syndromes, but can be divided into more useful group s on the basis of clinical, serologic, and immunogenetic features.