Background/Purpose: The aim of this study is to describe four of the most common autoantibodies against components of the Th/To complex: hPOP1, RPP25, RPP30, and RPP40. We report their prevalence and clinical characteristics in a systemic sclerosis (SSc) population, and determine whether these specificities associate with cancer.

Methods: A case control study was performed utilizing data from the Johns Hopkins Scleroderma Center Cohort. A total of 804 adult patients with SSc were included; 401 SSc patients with no history of cancer after at least 5 years of disease were compared to 403 SSc patients who ever had a history of cancer. Antibodies against hPOP1, RPP25, RPP30, and RPP40 were  assayed by immunoprecipitation of ³⁵S-methionine-labeled proteins generated by in vitro transcription/translation.  Demographic and clinical characteristics were compared between groups.

Results: 67/804 (8.3%) of patients had antibodies against any component of the Th/To complex. Patients with antibodies to any component were significantly more likely to have limited cutaneous disease, less likely to have tendon friction rubs, and more likely to have findings consistent with interstitial lung disease or pulmonary hypertension. Patients with antibodies against hPOP1, RPP25, RPP30, and/or RPP40 were significantly less likely to develop cancer within 2 years of SSc-onset (0% vs 11%, p=0.016).

Conclusion: The majority of SSc patients produce autoantibodies to multiple components of the Th/To complex, and have a clinical phenotype characterized by limited cutaneous disease and pulmonary involvement. Our findings show that the presence of any Th/To autoantibody may have a protective effect against contemporaneous cancer.

« Back to ACR Convergence 2020

ACR Meeting Abstracts - https://acrabstracts.org/abstract/cancer-in-systemic-sclerosis-analysis-of-antibodies-against-components-of-the-th-to-complex/