Severe migratory polyarthritis following in vivo CAMPATH-1G.

CAMPATH-1G is an IgG2b rat antihuman (CDw52) monoclonal antibody (MoAb) which is currently being used for T cell depletion in the setting of allogeneic bone marrow transplantation (BMT). In addition it elicits substantial lymphoid depletion, an effect which is being explored for remission induction in patients with lymphoid malignancies and for treating patients with various autoimmune disorders, in particular rheumatoid arthritis. Recently, in vivo CAMPATH-1G has been introduced to achieve increased immunosuppression in the pretransplant conditioning, for prevention of graft rejection following T cell depleted BMT. Here we describe a patient with T cell lymphoblastic lymphoma who received in vivo CAMPATH-1G as part of the pretransplant conditioning regimen and who, 6 days after the first dose, developed severe migratory polyarthritis. This is the first report of severe migratory polyarthritis as a very unusual complication following CAMPATH-1G MoAb administration.