CD38 and synovial sarcoma: The percentage of the circulating CD4+CD38+ subset in SS patients was significantly lower as compared with that of the age- and sex-matched healthy donors (median in SS = 9%; 25th–75th percentiles = 4%–19% versus median in healthy controls = 27%; 25th–75th percentiles = 22%–34%) (Mann–Whitney test: P < 0.0001) (Figure 2).