CD38 and synovial sarcoma: Interestingly, a retrospective study in 76 SS patients found that, although most SS patient cells were CD38-negative, a subset of patients (5 out of 76, 6.6%) had more than 50% of circulating CD4+CD38+ cells, often associated with a high number of circulating Sézary cells and a high CD4/CD8 ratio [41].