HLA allele polymorphisms among patients in hematopoietic stem cell transplantation program

U ovom radu analizirana je raspodjela alela i haplotipova HLA kod bolesnika uključenih u program nesrodne transplantacije krvotvornih matičnih stanica (TKMS) u Hrvatskoj, s ciljem određivanja vjerojatnosti pronalaska HLA podudarnog nesrodnog darivatelja. Unutar skupine od 150 nesrodnih bolesnika, određena je raspodjelu alela HLA-A, -B, -C, -DRB1 i -DQB1 te haplotipova HLA-A-B-DRB1, odnosno HLA-A-B-C-DRB1-DQB1. Aleli HLA određeni su metodama lančane reakcije polimerazom upotrebom specifičnih DNA početnica i oligonukleotidnih proba za alele HLA (metode: PCR-SSP i PCR-SSO). Haplotipovi HLA bolesnika određeni su segregacijskom analizom na temelju podataka o tipizaciji HLA članova uže obitelji. Usporedbom učestalosti alela HLA između ispitivane skupine bolesnika i zdrave kontrole nisu utvrđene statistički značajne razlike. Najčešći aleli bili su: HLA-A*02:01 (27,7%), B*51:01 (13,0%), C*07:01 (20,3%), DRB1*03:01 (15,3%) i DQB1*03:01 (23,3%). Od 227 različitih haplotipova HLA-A-B-DRB1, njih 197 pojavilo se samo jednom, a najzastupljeniji je bio: HLA-A*01:01-B*08:01-DRB1*03:01 (7,3%). Analiza haplotipova HLA koja je uključila 5 lokusa potvrdila je najveću učestalost haplotipa: HLA-A*01:01-B*08:01-C*07:01-DRB1*03:01-DQB1*02:01 što je u skladu s prethodnim istraživanjima. Neuobičajene kombinacije alela HLA-B-C uočene kod 15 bolesnika i neuobičajene kombinacije alela HLA-DRB1-DQB1 uočene kod 4 bolesnika te prisustvo rijetkih alela (A*29:01, B*80:01, C*07:18, DRB1*04:15, DRB1*11:15 i DRB1*11:28) pokazali su se kao otežavajući čimbenici u pronalasku HLA podudarnog nesrodnog darivatelja.The aim of the present study was to analyze the distribution of HLA alleles and haplotypes among patients (N=150) in hematopoietic stem cell transplantation program (HSCT) in Croatia, in order to determine the probability of finding an HLA matched unrelated donor. The distribution of HLA-A, -B, -C, -DRB1, -DQB1 alleles and HLA-A-B-DRB1/HLA-A-B-C-DRB1-DQB1 haplotypes was investigated. HLA alleles were tested by Polymerase Chain Reaction with specific primers or probes (PCR-SSP and PCR-SSO). HLA haplotypes were determined by segregation analysis. Comparison of patients included in this study and healthy controls regarding the HLA allele distribution did not reveal any statistically significant difference. The most common alleles detected in our patient group were: HLA-A*02:01 (27.7%), B*51:01 (13.0%), C*07:01 (20.3%), DRB1*03:01 (15.3%) and DQB1*03:01 (23.3%). Out of 227 different detected HLA-A-B-DRB1 haplotypes, 197 were observed only once and the most frequent one was HLA-A*01:01-B*08:01-DRB1*03:01 (7.3%). Five loci haplotype analysis confirmed the highest frequency of HLA-A*01:01-B*08:01-C*07:01-DRB1*03:01-DQB1*02:01 haplotype, which is in concordance with the previous studies. Unusual HLA-B-C combinations detected in 15 patients together with unusual HLA-DRB1-DQB1 combinations detected in four patients and the presence of rare alleles (A*29:01, A*80:01, C*07:18, DRB1*04:15, DRB1*11:15, DRB1*11:28) were shown to be limiting factors in finding an HLA matched unrelated donor