ABSTRACT
OBJECTIVE: To understand if autoantibodies account for racial variation in disease severity, we compared autoantibody distribution and associated phenotype between self-identified black and white systemic sclerosis (SSc) patients. METHODS: 803 black and 2178 white SSc patients had systematic testing for autoantibodies using Euroimmun (centromere (ACA), RNA-polymerase III (POLR3), Scl70, PM/Scl, NOR90, Th/To, Ku, U3RNP and Ro52) and commercial ELISA (U1RNP). In this observational study, logistic regression was performed to assess the association between self-identified race and outcomes, adjusting for autoantibodies. To estimate whether the effect of race was mediated by autoantibody status, race coefficients from multivariate models including and excluding autoantibodies were compared. RESULTS: Anti-Scl70, anti-U1RNP, anti-U3RNP, anti-Th/To, anti-Ku and anti-NOR90 were more common in the black cohort than in the white cohort, which was enriched for ACA, anti-POLR3 and anti-PM/Scl. Black individuals had a higher prevalence of severe Raynaud's, skin, lung, gastrointestinal and renal disease whereas white individuals had a higher prevalence of severe heart and muscle disease. Adjusting for autoantibodies decreased the effect of race on outcome for telangiectasias, forced vital capacity <70%, pulmonary hypertension and severe lung, heart, muscle and gastrointestinal disease by 11%-44% and increased the association between race and renal crisis and severe kidney disease by 37%-52%. CONCLUSIONS: This study is the largest systematic analysis of autoantibody responses in a geographically diverse population of black SSc patients. Black and white individuals with SSc have distinct autoantibody profiles. Autoantibodies explain only a fraction of the effect of race on clinical outcomes, suggesting other factors contribute to disparate outcomes between these groups.
ABSTRACT
OBJECTIVE: OPC-28326 is a selective alpha-adrenergic antagonist with preferential binding to the alpha(2C)-adrenergic receptor (alpha(2C)-AR) subtype. This study observed the effect of OPC-28326 on skin temperature and digital blood flow following an acute cold challenge in patients with Raynaud's phenomenon secondary to scleroderma. METHODS: The study was designed as a single-center, double-blind, placebo-controlled, randomized, 3-period crossover study of OPC-28326 (oral doses of 10 mg or 40 mg) or placebo. The primary outcome measures were the time to recover 50% and 70% of the fall (induced by cold challenge) in baseline digital skin temperature. RESULTS: Twelve of 13 enrolled patients completed the study. The mean time to achieve 50% and 70% recovery of the change in prechallenge digital skin temperature was shorter after the OPC-28326 40-mg dose than after placebo (50% recovery at 5.8 minutes versus 10.0 minutes [P = 0.02]; 70% recovery at 13.8 minutes versus 19.5 minutes [P = 0.01]). These recovery times tended to be shorter in the 10 mg OPC-28326 group as well, but the difference versus placebo was not significant (50% recovery at 9.0 minutes versus 10.0 minutes [P = 0.65]; 70% recovery at 15.3 minutes versus 19.5 minutes [P = 0.07]). Total digital blood flow tended to be lower prior to the cold challenge and after administration of 40 mg OPC-28326, as compared with that after placebo, but the difference was not significant. Symptoms that were potentially drug-related were reported more frequently with 40 mg OPC-28326 than with 10 mg OPC-28326 or with placebo, but none were serious or sustained. CONCLUSION: OPC-28326 at doses of 10 mg and 40 mg was well tolerated during this study. The shorter time to skin temperature recovery after 40 mg OPC-28326 suggests that selective alpha(2C)-AR blockade improves digital skin perfusion during recovery from cooling in patients with Raynaud's phenomenon secondary to scleroderma.
