Comparison between the HLA frequencies of volunteer donors recruited in the Campania bone marrow donor registry and the Italian population (IBMDR)

"Background: The high polymorphism of the HLA system reduces the probability of finding an unrelated patient HLA full-match with Bone Marrow Donor (BMD). This study represents the first investigation in the BMD Registry of Campania Region (RRNA01) in Italy of the HLA-A,-B,-Cw,-DR and –DQ frequencies. Aims: The purpose of this study was to assess genetic diversity between Campania Region and Italian population increasing compatibility chances with potential hematopoietic stem cells recipients. Methods: Serological tissue typing National Institute Health (NIH) standard method was used from 1990 to 2000 for HLA Class I (HLA-A,-B,-Cw loci) and Class II (HLA-DR,-DQ loci). This method has been integrated with low resolution molecular biology techniques SSP and\/or SSO for both the Classes (HLA-A*,-B*, -DRB* loci). From 2009 the HLA-DRB1* was typed only with high resolution. The HLA-C*, - DQB* loci was not typed more than default but only if request from Hematopoietic Stem Cell Transplant Center. Results: A large sample of 4126 volunteer donors registered on our Regional Registry from 1990 to 2011 were examined while only 19 occurred before 1990. In this large population, 1857 are male with 3582 living in the Naples area, while the remaining 544 are proportionally distributed in other Campania cities. The volunteer donors were selected according to local rules on blood donors to which they have been equalized. This study was also subdivided according to blood groups: 1668 group is 0 (45.6%), 1326 group A (36.3%), 137 group AB (3.7%), 526 group B (14.4%). However, for this variable, we have 469 (11.4%) missing data. In this study, most frequently patterns of antigens were HLA-A2 (41%), HLA-A24 (26.4%), HLA-B35 (31.4%), HLA B18 (20%), HLA-B51 (17.8%) HLA C4 7 (31%), HLA-CW4 (26.4%), HLA-DR11 (42%), HLA-DR7 (20.6%), HLA DQ7 (25.2%) and HLA DQ2 (15.8 %). Conclusions: These data show a genetic heterogeneity of the population of Regione Campania in comparison to Italian population. Further investigations are required to evaluate possible preferential associations (linkage disequilibrium) by using advanced molecular biology techniques.