TNFRSF9 and skin disorder: Compared to MRL-Faslpr mice, CD137-deficient MRL-Faslpr mice exhibited more severe SLE phenotype including pronounced splenomegaly, lymphadenopathy, dermatitis and glomerulonephritis, in addition to a significantly higher 5-month mortality rate than the MRL-Faslpr mice (80% versus 40%), with renal inflammation being the main cause of death [32].