LYMPHOPROLIFERATIVE DISORDER AND IMBALANCED T-HELPER RESPONSE IN C EBP-BETA-DEFICIENT MICE/

C/EBP beta is considered a key element of interleukin-6 (IL-6) signall ing as well as an important transcriptional regulator of the IL-6 gene itself. We describe here how mice lacking C/EBP beta develop a pathol ogy similar to mice overexpressing IL-6 and nearly identical to multic entric Castleman's disease in human patients, with marked splenomegaly , peripheral lymphadenopathy and enhanced haemopoiesis. Humoral, innat e and cellular immunity are also profoundly distorted, as shown by the defective activation of splenic macrophages, the strong impairement o f IL-12 production, the increased susceptibility to Candida albicans i nfection and the altered T-helper function, Our data show that C/EBP b eta is crucial for the correct functional regulation and homeostatic c ontrol of haemopoietic and lymphoid compartments.