CD3&sup+; CD57&sup+; 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 (> 1 year post-transplantation) allograft recipients showed a significant increase in the proportion of CD3⁺57⁺ lymphocytes (> 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-Vβ 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. [ABSTRACT FROM AUTHOR]