TNFSF13B and synovial sarcoma: In particular, IFNs are involved in both the early stage of innate immunity, during which the type I IFN is elevated in glandular tissue and sera [7] and the later phase of disease progression, by type I and type II IFN producing T cells and B cells [8], which is stimulated by B-cell-activating factor (BAFF) in SS [2] (Figure 1).