SYNOVIAL TISSUE-RESPONSE TO TREATMENT WITH CAMPATH-1H

Objective. Therapeutic trials in rheumatoid arthritis with the monoclo nal antibody Campath-1H have demonstrated recurrent clinical synovitis in some patients, despite profound depletion of circulating lymphocyt es. This study was undertaken to examine the cellular infiltrates in s ynovial tissue at a time of persistent peripheral lymphopenia. Methods . Immunohistochemical staining of synovial tissue and peripheral blood lymphocyte phenotyping. Results. Synovial tissues from 2 patients wit h recurrent synovitis after Campath-1H therapy contained significant T lymphocytic infiltrates at a time when circulating T lymphocytes were markedly depleted. Conclusion. These results demonstrate that periphe ral blood analysis may not accurately reflect the synovial tissue resp onse to monoclonal antibody therapy.