A population based, case control study of non-Hodgkin's lymphoma in patients with rheumatoid arthritis.

Objective: Epstein-Barr virus (EBV) associated lymphoproliferative disorders (LPD) similar to those that occur in immunosuppressed solid organ recipients have been reported in patients with rheumatoid arthritis (RA). These LPD cause significant morbidity and/or mortality in a state of sustained immunosuppression, but may spontaneously regress if immunocompetence is restored. We determined the population based frequency of EBV associated LPD relative to all non-Hodgkin's lymphomas (NHL) that occur in the general population of patients with RA.

B cell maturation and selection at the marrow-periphery interface.

More than 95% of newly formed B cells die in the short interval spanning sIgM acquisition in the bone marrow and entry into the long-lived pool, suggesting that selective events dictating B cell longevity occur at this stage. These likely include both ligand-induced deletion as well as discrete events that mediate recruitment to the long-lived recirculating pool. We are probing these events through the examination of normal B cell differentiation during this critical period: the characterization of a natural mutation that blocks late maturation, an irradiation/autoreconstitution model of marrow-derived B cell differentiation, and the identification of life span regulatory genes whose expression changes within this window.