Normal B cell homeostasis requires B cell activation factor production by radiation-resistant cells.

The cellular source of B cell activation factor (BAFF) required for peripheral B cell survival/maturation is unknown. To determine the nature of BAFF-producing cells we established and analyzed reciprocal bone marrow (BM) chimeras with wild-type (WT) and BAFF-deficient mice. The results revealed that BAFF production by radiation-resistant stromal cells is completely sufficient to provide a necessary signal for B cell survival/maturation, as BAFF-/- BM cells transferred into lethally irradiated WT mice gave rise to normal numbers of follicular (FO) and marginal zone (MZ) B cell subpopulations. On the other hand, transfer of WT BM into BAFF-/- lethally irradiated mice resulted only in minimal reconstitution of mature FO B cells and no restoration of MZ B cells. Thus, in the absence of BAFF+/+ stromal cells, BAFF production by BM-derived cells, presumably by macrophages, dendritic cells, and/or neutrophils, was not at all sufficient to support normal B cell homeostasis. Interestingly, immunization of both types of chimeras stimulated high levels of antigen-specific antibody secretion, indicating that either stromal cell- or hematopoietic cell-derived BAFF is sufficient for B cell antibody responses.

A Case of Persistent Helicobacter pylori Infection Occurring with Anti-IgE Immunosuppression.

The increasingly widespread use of novel immunosuppressive drugs may lead to unexpected infectious complications. We report a case of persistent Helicobacter pylori (H. pylori) infection that failed to respond to antimicrobial therapy in a patient receiving omalizumab (Xolair™, Genentech USA Inc., San Francisco, CA and Novartis Pharmaceuticals, Basel, Switzerland), an anti-IgE monoclonal antibody approved by the FDA for treatment of severe persistent asthma. To our knowledge, this is the first case report linking an immunosuppressive regimen containing anti-IgE biologic therapy to persistent H. pylori infection.

Patient considerations in the management of ulcerative colitis: role of once-daily MMX mesalamine.

Mesalamine and its derivatives are effective and well-tolerated therapies for ulcerative colitis. However, patient adherence to traditional mesalamine-based therapy is poor, and is often limited by heavy pill burdens and frequent dosing intervals. This can lead to ineffective disease control, impaired quality of life, and preventable morbidity and mortality. Previous studies have suggested that a once-daily mesalamine regimen would be strongly adhered to in the outpatient setting, but at that time no such formulation of mesalamine existed. In 2007, clinical trial data showed a novel, once-daily, multi-matrix (MMX) formulation of mesalamine to be effective in both remission induction and remission maintenance. This breakthrough in drug delivery allowed the unification of an effective therapeutic with a formulation that enables outpatients to be increasingly adherent to their medication. In theory, this might result in improved outpatient disease control and a decreased number of flares. As the use of MMX mesalamine increases, studies examining the outpatient community adherence rate need to be performed.