TNF and Salla disease: Several studies comparing the transcriptomes of DF and SD patients have reported increased levels of cytokines, tumor necrosis factor alpha (TNF-α), interleukin 2 (IL-2), interleukin 6 (IL-6), interleukin 10 (IL-10), interleukin 12 (IL-12) and interferon gamma (IFN-γ) involved in host immune responses in SD patients [15–19].