TRIM21 and overlapping connective tissue disease: However, patients with MC/pSS overlap syndrome are often characterized by more severe clinico-prognostic evolution; they show a significant low rate of anti-RoSSA/LaSSB along with a high prevalence of mixed cryoglobulinemia, hypocomplementemia, systemic autoimmune manifestations, and complicating lymphomas (94, 97, 98).