RESUMEN
We estimated HLA allele and haplotype frequencies of the Saudi Arabian population from a sample of 45,457 registered stem cell donors. The most frequent HLA alleles were A*02:01g (18.5%), C*06:02g (16.1%), B*51:01g (14.1%), DRB1*07:01g (16.2%), DQB1*02:01g (30.5%), and DPB1*04:01g (33.6%). The most frequent 5-locus haplotypes were A*02:05g~C*06:02g~B*50:01g~DRB1*07:01g~DQB1*02:01g (1.73%), A*02:01g~C*06:02g~B*50:01g~DRB1*07:01g~DQB1*02:01g (1.66%), and A*26:01g~C*07:02g~B*08:01g~DRB1*03:01g~DQB1*02:01g (1.38%). Furthermore, we used the calculated haplotype frequencies to estimate stem cell donor matching probabilities for Saudi Arabian donor and patient populations under various matching requirements. These results are relevant for strategic donor registry planning in the Kingdom of Saudi Arabia.
Asunto(s)
Selección de Donante/métodos , Antígenos HLA-D/genética , Trasplante de Células Madre Hematopoyéticas/métodos , Antígenos de Histocompatibilidad Clase I/genética , Alelos , Árabes/genética , Conjuntos de Datos como Asunto , Frecuencia de los Genes , Genética de Población/estadística & datos numéricos , Antígenos HLA-D/inmunología , Haplotipos , Antígenos de Histocompatibilidad Clase I/inmunología , Prueba de Histocompatibilidad , Humanos , Sistema de Registros/estadística & datos numéricos , Arabia Saudita , Donantes de TejidosRESUMEN
Saudi Arabia is the largest of the Arabian Gulf countries with a total population of 33.41 million as of 2017. This report summarizes the experience from four leading tertiary care hematopoietic stem cell transplantation (HSCT) centers in Saudi Arabia representing more than 90% of all HSCTs performed in the country. Between 1984 and 2016, a total of 6,184 HSCTs were performed. Of these, 3,586 HSCTs were performed in adults and 2,598 HSCTs were performed in pediatric patients. Malignancy was the main indication for transplantation (47%). While most transplants were performed from an identical sibling donor, HSCTs from cord blood, unrelated and, more recently, haploidentical donors have also been performed. Relative shortage of HSCT bed capacity is perceived to be a limiting factor in Saudi Arabia. Lately, more HSCT centers are emerging with rapid growth, which may significantly improve the access to HSCT in the country in the near future.
Asunto(s)
Trasplante de Células Madre Hematopoyéticas/historia , Atención Terciaria de Salud/historia , Donantes de Tejidos , Acondicionamiento Pretrasplante/historia , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Arabia SauditaRESUMEN
BACKGROUND: HLA-DQ donor-specific antibodies (DSA) are implicated in allograft dysfunction after renal and lung transplantation. Limited data exists on the impact of HLA-DQ antibodies on heart transplant patients. OBJECTIVE: To investigate the impact of DSA formation on allograft function and outcomes in heart transplant patients. DESIGN: Retrospective cohort study. SETTING: Collating post-transplantation patient data from computerized database in a tertiary hospital in Riyadh, Saudi Arabia from January 2006 to October 2014. PATIENTS AND METHODS: We excluded recipients with positive preoperative complement-dependent-cytotoxicity crossmatch grafts and those with preformed DSA. Anti-HLA antibodies were identified using Luminex-based assay in sera collected before transplantation with a routine endomyocardial biopsy the first year and then annually. MAIN OUTCOME MEASURES: Primary outcome measures were all-cause mortality, development of antibody mediated rejection, treated acute cellular rejection (ACR) and cardiac allograft vasculopathy (CAV). SAMPLE SIZE: 127 patients. RESULTS: DSA formation occurred in 43/127 (34%), with 33/43 (77%) targeting HLA-DQ antigens alone (n=7) or in combination with -DR, -A or B antibodies (n=26). Most (76%) were male and the mean (SD) age was 36 (14) years. Ten patients developed -A, -B or -DR antibodies without -DQ antibodies also present. Treated ACR (P=.011), reduced left ventricular ejection fraction (P less than .001), CAV development (P=.003), and all-cause mortality (P=.01) were all significantly more prevalent in the DSA-positive cohort. CONCLUSION: HLA-DQ donor-specific antibodies were the most common type detected and may play a significant role in poor outcomes post-cardiac transplantation. This emphasizes the importance of HLA-DQ matching and monitoring for DSA formation in order to minimize post-transplantation immunological risk. LIMITATIONS: Retrospective design comes with inherent biases, results from single institute, with a particularly young cohort. CONFLICT OF INTEREST: None.