Similar to intact mice, Card9−/− bone marrow chimeras also showed partial protection from arthritis development in the K/B × N serum-transfer model (Supplementary Figs 2a–d; P values between 9.1 × 10−11 and 1.6 × 10−4; two-way ANOVA), indicating a role for CARD9 in a radiosensitive hematopoietic compartment. This evidence concerns the gene CARD9 and Arthritis.