These included 6/17 (35%) SS patients (mean 0.57 pg/mL, range 0.20–1.39 pg/mL) and 5/21 (24%) FMF patients (mean 0.33 pg/mL, range 0.20–0.43 pg/mL); IL31 could not be detected in classic MF. The gene discussed is IL31; the disease is synovial sarcoma.