TRIM21 and lymphoma: The differences in the phenotypes between Italians and Greeks, seem to share some common features in the young and the old pSS patients (e.g., chronic fatigue, anti-Ro/SSA positivity, lymphadenopathy, leukopenia, skin ulcers, low C4, and lymphoma), suggesting that genetic, environmental, and socioeconomic variations may drive the different biologic and immunologic responses between the 2 ethnic groups, independently of age.