KIR genotype and haplotype repertoire in Kuwaiti healthy donors, hematopoietic cell transplant recipients and healthy family members

The gene complex located on chromosome 19q13.4 encodes the Killer-cell Immunoglobulin-like Receptors (KIRs), which exhibit remarkable polymorphism in both gene content and sequences. Further, the repertoire of KIR genes varies within and between populations, creating a diverse pool of KIR genotypes. This study was carried out to characterize KIR genotypes and haplotypes among 379 Arab Kuwaiti individuals including 60 subjects from 20 trio families, 49 hematopoietic cell transplantation (HCT) recipients and 270 healthy Kuwaiti volunteer HCT donors. KIR Genotyping was performed by a combination of reverse sequence specific oligonucleotide probes (rSSO) and/or Real Time PCR. The frequencies of KIR genes in 270 healthy Kuwaiti volunteer donors were compared to previously reported frequencies in other populations. In addition, we compared the differences in KIR repertoire of patients and healthy donors to investigate the reproducibility of previously reported significant differences between patients with hematological malignancies and healthy donors. The observed frequencies in our cohort volunteer HCT donors was comparable to those reported in neighboring Arab populations. The activating genes KIR2DS1, KIR2DS5 and KIR3DS1 and the inhibitory gene KIR2DL5 were significantly more frequent in patients compared to healthy donors, however, none of the previously reported differences were reproducible in our Kuwaiti cohort. This report is the first description of KIR gene carrier frequency and haplotype characterization in a fairly large cohort of the Kuwaiti population, which may have implications in KIR based HCT donor selection strategies.We thank Amanda Willis and Shawna Kennedy from Baylor University Medical Center for assisting in the initial analysis of KIR genotyping data. We are very grateful for Basil Khuder, the bioinformatics scientist at Phoenix Children's Hospital for imputing the missing KIR gene carrier frequency required to generate the PCA graphical representation. This research was supported by a grant from the Kuwait Foundation for the Advancement of Sciences, Kuwait (P116-13MC-08) and Research Core Facility of the Health Sciences Center (RCF - Grant No: SRUL02/13), Kuwait University, Kuwait.Scopu

Primary mediastinal large B-cell lymphoma: Clinical features, prognostic factors and survival with RCHOP in Arab patients in the PET scan era

Objective: PMBCL is a distinct type of nonhodgkins lymphoma with specific clinicopathological features. To clarify clinical features, treatment alternatives and outcomes, we evaluated 28 Arab patients treated with chemotherapy or radiotherapy between 2006 and 2011. Patients and Methods: PMBCL lymphoma patients identified according to WHO classification and treated at KCCC between 2006 and 2011 were included in this study. Demographic and clinical data are presented as means or medians. Overall survival was estimated using the Kaplan-Meier method. Survival rates were compared using the log-rank test. A P < 0.05 was considered significant. Results: The median age of the patients was 31 years and the male to female ratio was 2:1. Majority of the patients (75%) presented with stage I/II disease. Most had features of local extension like pleural effusion (18%) and SVCO (39%). Only 11% of the patients had bone marrow involvement at presentation. 96% of the patients required biopsy from the mediastinal mass either by image guided core biopsy (75%) or by surgical biopsy. Most patients were treated by RCHOP and involved field radiotherapy. Patients with positive PET scan after RCHOP chemotherapy received salvage chemotherapy and BEAM autologous marrow transplant. The five year OS for the entire group was 85% while the PFS was 73%. Patients who had PET scan for response evaluation had better OS [P = 0.013] and PFS [P = 0.039] when compared with those patients who received only radiotherapy based on CT scan evaluation. Conclusion: PMBCL is a specific lymphoma entity seen in the young with good survival. The role of PET scan for response evaluation and the type of consolidation therapy needs to be further clarifie

Next-generation HLA typing of 382 International Histocompatibility Working Group reference B-Lymphoblastoid cell lines : report from the 17th International HLA and Immunogenetics Workshop

Extended molecular characterization of HLA genes in the IHWG reference B-lymphoblastoid cell lines (B-LCLs) was one of the major goals for the 17th International HLA and Immunogenetics Workshop (IHIW). Although reference B-LCLs have been examined extensively in previous workshops complete high-resolution typing was not completed for all the classical class I and class II HLA genes. To address this, we conducted a single-blind study where select panels of B-LCL genomic DNA samples were distributed to multiple laboratories for HLA genotyping by next-generation sequencing methods. Identical cell panels comprised of 24 and 346 samples were distributed and typed by at least four laboratories in order to derive accurate consensus HLA genotypes. Overall concordance rates calculated at both 2- and 4-field allele-level resolutions ranged from 90.4% to 100%. Concordance for the class I genes ranged from 91.7 to 100%, whereas concordance for class II genes was variable; the lowest observed at HLA-DRB3 (84.2%). At the maximum allele-resolution 78 B-LCLs were defined as homozygous for all 11 loci. We identified 11 novel exon polymorphisms in the entire cell panel. A comparison of the B-LCLs NGS HLA genotypes with the HLA genotypes catalogued in the IPD-IMGT/HLA Database Cell Repository, revealed an overall allele match at 68.4%. Typing discrepancies between the two datasets were mostly due to the lower-resolution historical typing methods resulting in incomplete HLA genotypes for some samples listed in the IPD-IMGT/HLA Database Cell Repository. Our approach of multiple-laboratory NGS HLA typing of the B-LCLs has provided accurate genotyping data. The data generated by the tremendous collaborative efforts of the 17th IHIW participants is useful for updating the current cell and sequence databases and will be a valuable resource for future studies