C3 and interstitial lung disease: SSc‐ILD patients had higher C3 levels (90.60 [77.60–99.80] vs 72.40 [67.85–83.08], p = 0.04552) and C4 levels (18.60 [15.80–23.20] vs 16.20 [12.95–21.40], p < 0.001) compared with SSc‐nonILD patients.