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We have typed 25 homozygous B lymphoblastoid cell lines, defined as reference panel during the Xth International Histocompatibility Workshop, using PCR (Polymerase Chain Reaction) and oligonucleotidic probes recognizing sequences of DQA and DQB genes. The polymorphism of 8 HLA-DQA1, and 12 DQB1 alleles is reported and the advantages of this technique are compared to that of other typing methods, currently used.

The results study of renal allograft performed in the France-Transplant network, shows the beneficial effect of blood transfusions on graft survival; their immuno-suppressive effect allowed the tolerance of the transplant, despite of the presence, at times, of incompatibilities HLA. In this work, we have studied the effect of HLA-A, B, DR incompatibilities in 803 unrelated recipients according to their preimmunized status. In the 303 presensitized patients (by transfusion or transplantation) we show clearly the strong effect of the HLA compatibility and the additive effect of the three loci A, B, DR (94% of graft survival at two years for the best matched v.s. 36% for the worst). In the 500 non responder patients, there is no effect of the compatibility A, B, DR (69% for the best matched v.s. 71% for the worst). Presensitized patients reach currently 50% of the waiting list of dialysed. Cooperative efforts should avoid heavily mismatched transplants in case of preimmunization.

1. Beneficial effect of HLA matching is observed mainly among sensitized recipients. 2. Two DR and at least 1A and 1B antigen shared between donor and recipient significantly improve the results at 5 years.

A simulation of the matching for HLA-DR, B, A loci was achieved by taking into account the practical situation of kidney transplants for 89 donors and 322 potential recipients. A complete HLA-DR identical graft was theoretically possible in 52% of the cases. Conversely, if the identity for B or particularly the identities for both B and A were sought, the necessary pool of recipients would have to be much larger, requiring intense international cooperation.

ANASER is a system of 3 computer programs for the analysis of sera from multi-transfused patients, multiparous women and dialysed patients awaiting kidney transplantation, which react against one or more HLA antigens. This system permits: 1) the recognition of one or more HLA specificities in each serum using iterative analyses. 2) The calculations of correlation coefficients among several sera. 3) The drawing of positive serological reactions according to either a given sera or to a given antigen. It can be used for two main purposes: 1) to permit selection of the best sera for HLA typing (positive correlations). 2) To study the preimmunization of dialysed patients awaiting kidney graft. Owing to sequential comparison of the consecutive bleedings from the same individual, they allow the definition of a pattern of anti-HLA immunisation, and in the case of large spectrum antibodies, the specification of antigens not concerned by the antibodies produced (negative correlations). ANASER may help in the choice of the best compatible transplant for hyperimmunized patients, who need a precisely matched organ.