HLA-Cw typing in Italian unrelated stem cells donors (MUD)

About 70% of patients who could benefit of an haematopoietic stem cells transplant do not find a suitable familial donor, so that a MUD is searched. In order to asses the allelic donor/recipient matching, HLA Class I and II molecular typing is currently used in place of serology. The aim of this study is to compare HLA-Cw typing results obtained by serological and molecular methods (BM) in 295 random MUD. BM analyses were performed using an Enzyme Linked Probes Hybridization Assay (ELPHA) HLA-C LowRes Biotest kit; in 54 samples obtained results were ambiguous and a PCR-SSP method (Dynal) was further used. The comparison revealed a discrepancy rate of 24,41% due to: antigens "missed" by serology (20,34%); incorrect (3,39%) or additional (0,68%) serological assignment. This work confirms previous studies indicating that BM techniques are more reliable than serological methods in defining HLA-Cw specificities. We emphasized here the high rate of serologic "blanks", probably due to low expression of HLA-Cw antigens and technical serological lacks. Serological HLA-Cw typing does not appear suitable to supply the precise HLA donor/recipient typing, because of the high level of missed and/or incorrect antigens assignment.