Usefulness of frequency analysis of cytotoxic T-lymphocytes precursors (CTL-p) for selection of HLA matched unrelated marrow donors.

A child with Sanfilippo syndrome and 5 potential unrelated marrow donors were typed serologically, tested in mixed lymphocyte reaction and typed by restriction fragment length polymorphism analysis in attempt to find a suitable donor. All donors were found to be identical with the recipient, however, these studies were not conclusive in identifying the best match donor. Therefore, recipient-donor pairs were examined by HLA-DR oligotyping. In addition we have studied the potential of cytotoxic T-lymphocytes precursors (CTL-p) analysis as a means of selection for matched unrelated donors. Low frequencies (1/10(5)) of pretransplant CTL-p correlated with oligotyping identity in all donor-recipient pairs evaluated. In one case oligotyping disclosed a previously unrecognized HLA-DRB1 disparity. This resulted in high frequencies of CTL-p (1/35,000). Based on this experience we can argue that CTL-p analysis may be used as an additional tool for selection of compatible unrelated marrow donors.