Low copy number of the IgG receptor FcγRIIIb gene FCGR3B, which facilitates clearance of ICs, was associated with risk for developing isolated SS in a cross-sectional study of 174 SS patients compared to 162 controls (OR 2.3, 95 % CI 1.3–3.9, p = 0.003) [83]. Here, FCGR3B is linked to synovial sarcoma.