Objective: To determine the clinical and immunogenetic features of systemic sclerosis (SSc) patients with anti-Th/To autoantibodies.
Methods: HLA class II alleles were determined by DNA oligotyping in a large group of SSc patients with anticentromere antibodies (ACA), anti-topoisomerase I (anti-topo I), and anti-Th/To autoantibodies.
Results: Clinical features of the 28 anti-Th/To-positive SSc patients were similar to those observed in the 56 ACA-positive SSc patients, except for a decreased frequency of gastrointestinal involvement in anti-Th/To-positive patients. Immunogenetic analysis revealed a significant increase in the frequency of HLA-DR11 in the anti-Th/To-positive and the anti-topo I-positive patients. The anti-Th/To-positive patients also had a significant reduction in the frequency of HLA-DR7, similar to that seen in ACA-positive SSc patients.
Conclusion: Despite clinical and immunogenetic similarities with both the ACA- and anti-topo I-positive patients, anti-Th/To-positive SSc patients present a characteristic pattern of clinical and immunogenetic features that may have implications regarding etiology, pathogenesis, and treatment.