Characterization of a novel allele, HLA-C*02:135N, by full-length gene sequencing in a bone marrow donor.

A frameshift because of a two-nucleotide deletion results in an HLA-C null allele, HLA-C*02:135N.

A novel HLA-A*26 allele, HLA-A*26:01:44, identified in a Caucasian individual.

HLA-A*26:01:44 differs from HLA-A*26:01:01 by a single substitution in exon 5.

The novel HLA-B*08:183 allele identified by sequence-based typing in a Caucasian leukemia patient.

HLA-B*08:183 differs from HLA-B*08:01:01 by a single substitution in exon 5.

HLA-DQB1*05:144, a novel allele, discovered in a Southeast Asian donor for stem cell transplantation.

HLA-DQB1*05:144 differs from HLA-DQB1*05:01:01 by a single substitution in exon 3.

A novel HLA-B*18 allele, HLA-B*18:124, identified in a German volunteer bone marrow donor.

HLA-B*18:124 differs from B*18:01:01:02 by a single substitution in exon 4.

HLA-A*23:01:19, a novel variant of HLA-A*23:01, discovered in a West African stem cell transplantation patient.

HLA-A*23:01:19 differs from HLA-A*23:01:01 by a single substitution in exon 4.

Identification of the novel allele, HLA-B*27:131.

The novel allele, HLA-B*27:131, was identified and full genomic DNA was successfully cloned.

Randomized controlled trial of high-dose intradermal versus standard-dose intramuscular influenza vaccine in organ transplant recipients.

The immunogenicity of standard intramuscular (IM) influenza vaccine is suboptimal in transplant recipients. Also, recent studies suggest that alloantibody may be upregulated due to vaccination. We evaluated a novel high-dose intradermal (ID) vaccine strategy. In conjunction, we assessed alloimmunity. Transplant recipients were randomized to receive IM or high-dose ID vaccine. Strain-specific serology and HLA alloantibody production was determined pre- and postimmunization. In 212 evaluable patients (105 IM, 107 ID), seroprotection to H1N1, H3N2 and B strains was 70.5%, 63.8% and 52.4% in the IM group, and 71.0%, 70.1%, 63.6% in the ID group (p=ns). Seroconversion to ≥1 antigen was 46.7% and 51.4% in the IM and ID groups respectively (p=0.49). Response was more likely in those≥6 months posttransplant (53.2% vs. 19.2%; p=0.001). Use of mycophenolate mofetil was inversely associated with vaccine response in a dose-dependent manner (p<0.001). Certain organ subgroups had higher response rates for influenza B in the ID vaccine group. Differences in anti-HLA antibody production were detected in only 3/212(1.4%) patients with no clinical consequences. High-dose intradermal vaccine is an alternative to standard vaccine and has potential enhanced immunogenicity in certain subgroups. In this large cohort, we also show that seasonal influenza does not result in significant alloantibody production.

Assessment of fidelity and utility of the whole-genome amplification for the clinical tests offered in a histocompatibility and immunogenetics laboratory.

Increasing emphasis on the use of molecular tests in a histocompatibility and immunogenetics laboratory (HIL) poses a potential problem of lack of sufficient DNA to perform multiple genetic analyses. In this study, we report the feasibility, fidelity and utility of multiple displacement amplification (MDA) method to perform whole-genome amplification (WGA) to generate DNA specimens that can be analyzed by multiple molecular techniques and can be used for different clinical tests offered by an HIL. The MDA-generated DNA when compared with the native DNA showed 100% congruency in genotyping of 37 genes/loci using multiple downstream molecular techniques: sequence-based typing and sequence-specific primer-based typing for 5 human leukocyte antigen (HLA) class I and II genes (HLA-A, B, C, DRB1 and DQB1), luminex-based sequence-specific oligonucleotide (SSO) genotyping for a panel of 16 killer immunoglobulin-like receptor (KIR) genes and automated fragment size analysis for a panel of 15 short tandem repeat (STR) loci and amelogenin gene. For post-allogeneic hematopoietic cell transplantation (HCT) chimerism analysis, MDA-generated DNA appeared useful for enriching pre-transplant DNA but not for enriching post-transplant chimeric DNA. Overall, our results show that MDA-based WGA could generate DNA of high yield and fidelity that can be used for various clinical tests and research purposes.

A novel HLA-B allele, B*4093, sharing sequences with B*4006 and B*0702 in an Asian Indian donor.

A new HLA-B allele (B*4093) in a North Indian Hindu donor differing from B*4006 by four nucleotide substitutions in codon 41.1, codon 44.3, codon 45.1 and codon 50.3 has been identified. This novel allele was part of the A*0211-B*4093-Cw*1502-DRB1*15-DQB1*06 HLA haplotype.

Advances in type I diabetes associated tolerance mechanisms.

Type 1 diabetes (T1D) is an autoimmune disease resulting from the destruction of insulin-producing pancreatic beta cells by autoreactive T cells. The polygenic trait for T1D risk implicates many genes that have an impact on fundamental immunological processes such as central and peripheral tolerance. Several pieces of evidence have suggested that many of the genetic loci that are directly linked to type 1 diabetes susceptibility modulate the generation and/or the activation of autoreactive T-lymphocytes. We and others have proposed a critical role for medullary thymic epithelial cells (mTEC) forming the Hassall's corpuscles in T-cell tolerance. Indeed, mTEC have been found to express promiscuous self-antigens, used directly or through thymic dendritic cells to drive either negative selection of insulin-reacting precursors or their differentiation into naturally occurring regulatory Foxp3+ CD4+ CD25+ T cells. In the periphery, naturally occurring Foxp3+ CD4+ CD25+regulatory T (Treg) cells represent the master cells in dominant peripheral T-cell tolerance. The development and function of Treg cells are ultimately linked to IL-2 and Foxp3 expression. This review addresses recent literature and emerging concepts of central and peripheral T-cell tolerance with regards to T1D.

Early age of disease onset in African American type 1 diabetes patients is associated with DQB1*0201 allele.

The goal of this study is to assess the association of HLA-DQ alleles with the age of onset of type 1 diabetes in African American patients. Using PCR oligonucleotide typing, HLA-DQA1 and DQB1 alleles were determined. DQA1*0301, DQB1*0201, and DQB1*0302 were significantly increased in African American patients. However, the DQB1*0602 allele was decreased in these patients. In addition, DQA1*0401 and DQB1*0402, were associated with protection in African Americans. When stratified by age of onset, prepubertal patients showed an absence of the protective allele DQB1*0602 and a significant increase in DQB1*0201 compared to postpubertal patients. The high frequency of the HLA-DQ susceptibility allele in pre-pubertal patients suggest that the biology of disease in this group may differ from type 1 diabetes with a later age of onset.