They had a higher frequency of hypergammaglobulinaemia (60.8% vs 26.6%, P < 0.001), RF positivity (41.5% vs 20.2%, P < 0.001), low C3 level (18.9% vs 9.1%, P = 0.032), low C4 level (54.7% vs 40.2%, P = 0.048) and autoantibodies [84.6% with anti-SSA vs 54.4% (P < 0.001) and 57.7% with anti-SSB vs 29.7% (P < 0.001)].