C4A and lymphoma: The main predictors of lymphoma development in patients with pSS are permanently enlarged salivary glands,8, 9, 10 palpable purpura,9, 10, 11 lymphadenopathies,8, 10 cryoglobulinaemia,10, 12 low complement levels (especially C4),9, 10, 11, 13 a monoclonal component in the serum or urine,8 and lymphopenia.11, 13 However, these studies evaluated risk factors for the development of the entire group of non‐Hodgkin's lymphomas, and did not indicate which predictors could lead to the development of a specific variant of non‐Hodgkin's lymphoma.