CD4 and synovial sarcoma: (30) reported the crucial study that focused on the difference between pSS and non-SS “Sicca” in terms of memory CD4+ T-cells and revealed that the proportions and numbers of memory CD4+ T-cells in the salivary gland were related to key SS features; however, the interrelationship between memory T-cells and the specificity of pSS is still not fully understood.