DCs accumulate both in T cell areas [7] and B cell areas [8] in the lymph nodes and spleens of lupus-prone MRL/lpr (Fas-deficient) and NZB-W/F1 mice; in the latter strain, the accumulation has been attributed to high levels of Flt-3L [9], which is also increased in patients with lupus [10]. The gene discussed is FAS; the disease is systemic lupus erythematosus.