A Study On HLA-DQA1 Gene Mismatching Proportion Of Donor-recipient Pairs And Their Impact On Outcomes In Unrelated Hematopoietic Stem Cell Transplantation

PART I A study of the frequencies of HLA-DQA1 alleles and their clinical application values in the donor-recipient HLA-10/10 matchedhematopoietic stem cell transplantationObjective: To analyze the frequencies of HLA-DQA1 alleles and their clinical values in the donor-recipient HLA-A,-B,-C,-DRB1,-DQB1(10/10) matched hematopoietic stem cell transplantation(HSCT).Methods: This study recruited 127 patients who received allogeneic HSCT and 127 unrelated donors. High-resolution(High Res)DNA typing for HLA-DQA1 alleles were performed on the 254 subjects by using sequence specific oligonucleotide probes(SSOP) and high resolution of sequence specific primer(High Res SSP).Results:The DQA1 allele genotypes of 36 pairs of donor-recipient were directly identified by using SSOP. The ambiguous DQA1 allele genotypes of the rest 91 pairs were identified by using High Res SSP. Among the 127 pairs of donor-recipient, 5 pairs were HLA-DQA1 alleles mismatched, while the others were all matched. No significant differences in the distribution of HLA-DQA1 alleles were observed between the donors and the recipients. Sixteen HLA-DQA1 alleles were detected in the 127 donors, which were DQA1*02:01(19.3%), DQA1*01:02(19.3%), DQA1*03:02/03(17.0%), DQA1* 01:03(9.8%), DQA1*06:01(9.1%), DQA1*05:01(7.1%), DQA1*05:05(5.9%), DQA1* 03:01(4.7%), DQA1*01:04(2.4%), DQA1*01:05(2.0%), DQA1*01:01(1.2%), DQA1* 05:03(0.8%), DQA1*05:08(0.8%), DQA1*04:01(0.4%), DQA1*05:06(0.4%) from high to low frequency. Moreover, a new allele was detected in the patients. The haplotypes’ frequencies and linkage disequilibrium(LD) analysis of HLA-DQA1 and HLA-DQB1 showed that the most common haplotype was DQA1*02:01-DQB1* 02:02(16.1%), followed by DQA1*03:02/03-DQB1*03:03(11.8%) and DQA1*01:03-DQB1*06:01(9.1%). Stronger LD were observed between DQA1*02:01 and DQB1*02:02, DQA1*03:02 and DQB1*03:03, DQA1*01:03 and DQB1*06:01, HLA-DQA1*06:01 and DQB1*03:01, DQA1*05:01 and DQB1*02:02(P<0.001).Conclusion:There was strong linkage disequilibrium between HLA-DQA1 and HLA-DQB1 genes. The polymorphism of HLA-DQA1 gene was less than that of HLA-DQB1 gene. No more guidance was provided to donor selection in unrelated donor-recipient HLAmatched HSCT by adding HLA-DQA1 genotyping, but it might have clinical application values in HSCT with HLAⅡ locus mismatched donor and recipient.PART II To study HLA-DQA1 gene mismatching proportion of donor-recipient pairs and the impact on outcomes in HLA mismatched unrelated allogeneic hematopoietic stem cell transplantationObjective To study HLA-DQA1 gene mismatching proportion of donor-recipient pairs and the impact on prognosis in HLA mismatched unrelated allogeneic hematopoietic stem cell transplantation(allo-HSCT).Methods 245 donor-patient pairs who received unrelated allo-HSCT in the First Affiliated Hospital of Sochow University from 2010 to 2015 were analyzed retrospectively. The diseases involved in acute myeloid leukemia(AML=105), acute lymphoblastic leukemia(ALL=67), chronic myelogenous leukemia(CML=25), myelodysplastic syndrome(MDS=32), hybrid acute leukemia(HAL=6). HLA-A,-B,-C,-DRB1,-DQB1 typing were performed using SBT, SSOP, and High Res.SSP. HLA-DQA1 was typed using SSOP.Result Of 245 donor-recipient pairs, 8 pairs were HLA-DQA1 antigen mismatched, among them, 3pairs were isolated antigen mismatched, 5pairs were mismatched associated wih other locus, including 3pairs with HLA-DQB1 antigen mismatch, the other two were respectively with HLA-DRB1 and HLA-C allele mismatch.Of 245 patients, The cumulative incidence of II-IV a GVHD was 33.9%(83/245). The overall recurrence rate was 20.6%, TRM was 20.2%. The percentage of 5-year OS was 62.2%. The OS from high to low in different disease were CML(80%), AA(75%), MDS(75%), AML(52.8%), ALL(52.8%), HLA-matched pairs had high overall survival(OS) than HLA-mismatched pairs(65.1%vs53.4%,P=0.164), II-IVa GVHD and transplant-related mortality(TRM) between the two groups were respectively 48.4%vs29.0%(P=0.003), 29.3%vs17.1%(P=0.05). Compared with HLA matched group, a single HLA allele mismatched group had higher II-IVa GVHD(52.0%vs29%,P=0.017). TRM in a single HLA antigen mismatched group was higher than HLA matched group(30%vs17.1%,P=0.059).Among different HLA loci mismatched groups, HLA-A allele mismatches has no any adverse effect on outcomes. In HLA-C locus mismatch, II-IV a GVHD was higher than HLA-matched group(53.3%vs29.0%, P=0.003). Meanwhile in 5-year OS, DFS, TRM and relapse, the proportion of the two groups were 46.4%vs65.1%、46.4%vs63.4%、32.1%vs 17.1%、25vs21.1%, P values were 0.087、0.129、0.064、0.622. Between a single HLA-C allele mismatched and HLA matched groups, II-IV a GVHD、OS、DFS、TRM, relapse were 57.1%vs29.0%、42.9%vs65.1%、42.9%vs63.4%、42.9%vs17.1%、28.6%vs 21.1%, P values were 0.0895、0.476、0.534、0.188、0.754. Between a single HLA-C antigen mismatch and HLA matched groups, II-IV a GVHD、OS、DFS、TRM、relapse were 50%vs29.0%、47.6%vs65.1%、47.6%vs63.4%、28.6%vs17.1%、23.8%vs21.1%. P values were 0.023、0.097、0.143、0.142、0.686.The cumulative incidence of II-IV a GVHD between a single DQB1 locus mismatched group and HLA-matched group was 72.7%vs29.0% with P<0.0001. Similarly, 5-year OS and DFS were lower than HLA matched group, the ratio was 45.5%vs65.1%, 45.5%vs63.4%, P values were respectively 0.069 and 0.067. TRM between this two groups was 36.4%vs17.1% with P=0.03. Between the two groups of a single DQB1 allele mismatch and a single DQB1 antigen mismatch, II-IV a GVHD、5-year OS、DFS、TRM were 80%vs66.7%(P=0.888) 、 20%vs66.7%(P=0.176) 、 20%vs66.7%(P=0.176) 、 40%vs 33.3%(P=0.647). Among different DQB1 allele mismatches, DQB1*06:XX was the most common, accounting for 80%(4/5), three patients died, four patients occurred of II-IV a GVHD.In 8 pairs DQA1 antigen mismatches, 5cases survived well at the last follow-up, 3cases died, 1case occurred recurrence, 3cases occurred of II-IV a GVHD. In an isolated DQA1 mismatch group, 2 cases died, 1case occurred relapse. In 3 DQA1 associated with DQB1 antigen mismatched group, 1case occurred recurrence, 1cases occurred II-IV a GVHD. In DQA1 antigen mismatch associated with DRB1 allele mismatch, 1cases occurred II-IV a GVHD.Conclusion HLA matching of donor-recipient pairs is an important factor to the transplantation prognosis in unrelated allo-HSCT. the results of our study provide evidence supporting the biological importance of HLA-DQB1 gene products in clinical transplantation, especially the various allele mismatches of DQB1*06:XX is an important risk factor for OS and a GVHD, In our study, DA1 antigen mismatches has no significant adverse effect on prognosis, so it should give priority to select other loci matching when selecting an unrelated donor.