CD3+ CD57+ lymphocytes are not likely to be involved in antigen-specific rejection processes in long-term allograft recipients.

Cytofluorometric investigation of peripheral blood lymphocytes in 380 long-term (greater than 1 year posttransplantation) allograft recipients showed a significant increase in the proportion of CD3+57+ lymphocytes (greater than 20%) in 20% of patients with renal allografts, 66% of patients with cardiac allografts and 44% of patients with liver allografts. Most of these CD3+57+ cells expressed the CD8 antigen and a variable proportion the HLA-DR antigen. A retrospective analysis showed a poorer prognosis for the clinical outcome in those patients with elevated numbers of CD3+57+ cells in peripheral blood. However, CD57+ lymphocytes could rarely be detected in renal infiltrates by immunohistology. Using the Southern blot technique to analyse the T cell receptor rearrangement of separated CD57+ cells, no clonal or oligoclonal expansion of T cell clones could be detected. Nevertheless, there might be a bias towards the use of particular TCR-V beta gene families in at least some patients, as shown by analysis with monoclonal antibodies. In summary, CD57+ T cells are not likely to be directly involved in the rejection process. The data support the idea of a polyclonal and/or superantigen-driven expansion, but not of an antigen-driven expansion of these cells.