Lymphocytes in pseudomembranes of late prosthetic joint failure

The pseudomembrane formed in association with late aseptic prosthesis failure contains a mixed giant cell and histiocytic infiltrate with variable numbers of lymphocytes. Immunolabelling with a panel of antibodies on paraffin sections was undertaken to define the nature of the lymphoid infiltrate in 19 cases. In all cases, the predominant lymphoid cell was a memory (CD45RO+, CD45RA-) T-cell. B-cells were rare. Tissue from patients with rheumatoid arthritis (RA) contained greater numbers of T-cells when compared with patients with osteoarthritis (OA), suggesting that the intensity of the lymphoid infiltrates reflects the underlying joint disease rather than necessarily being part of a hypersensitivity response to wear debris.