C4A and anemia: Those who developed MALT NHL had a higher frequency at diagnosis of cryoglobulins (P = 0.002), low C3 levels (P = 0.018), high EULAR SS disease activity index (ESSDAI) score of 4 or more (P = 0.001), and high joint DAS score (P < 0.001), while the risk of non-MALT B cell lymphomas was unrelated to systemic activity, with anaemia, monoclonal gammopathy, cryoglobulins and low C4 levels at SD diagnosis being the main risk factors.