Characterisation of the HLA-DQ alpha eplet 52SK targeting the DQA1*01 alleles family.

Eplet 52SK is unique in the HLA eplet registry as targeting the whole family of DQA1*01 alleles. It is proposed as an antibody-verified eplet but has not been validated enough to deserve this label. Especially, confusion can occur with reactivity targeting the 52PQ eplet which is present on the DQB1*05 and DQB1*06 alleles families, as DQ molecule stability imposes DQA1*01 to selectively associate with these DQ-β families only.

Identification of Antibodies to DQβ:DRα Interisotypic Heterodimers in Human Sera.

Background: HLA class II antigens, DR, DQ, and DP, comprised an α and β chains, which typically combine, within the same isotype, to form the major histocompatibility complex:peptide complex. Interisotypic pairing is not commonly observed. Although reports of DQβ:DRα heterodimers exist, the pairing was reported to be unstable and, therefore, not studied to any extent.

HLA class I peptide polymorphisms contribute to class II DQβ0603:DQα0103 antibody specificity.

Antibodies reactive to human leukocyte antigens (HLA) represent a barrier for patients awaiting transplantation. Based on reactivity patterns in single-antigen bead (SAB) assays, various epitope matching algorithms have been proposed to improve transplant outcomes. However, some antibody reactivities cannot be explained by amino acid motifs, leading to uncertainty about their clinical relevance.

Development and Validation of a Multiplex, Bead-based Assay to Detect Antibodies Directed Against SARS-CoV-2 Proteins.

Background: Transplant recipients who develop COVID-19 may be at increased risk for morbidity and mortality. Determining the status of antibodies against SARS-CoV-2 in both candidates and recipients will be important to understand the epidemiology and clinical course of COVID-19 in this population. While there are multiple tests to detect antibodies to SARS-CoV-2, their performance is variable.

Reassessment of the clinical impact of preformed donor-specific anti-HLA-Cw antibodies in kidney transplantation.

Anti-denatured HLA-Cw antibodies are highly prevalent, whereas anti-native HLA-Cw antibodies seem to lead to random flow cytometry crossmatch results. We aimed to reassess crossmatch prediction for anti-HLA-Cw using 2 types of single antigen flow beads (classical beads and beads with diminished expression of denatured HLA), and to compare the pathogenicity of preformed anti-denatured and anti-native HLA-Cw antibodies in kidney transplantation. We performed 135 crossmatches with sera reacting against donor HLA-Cw (classical beads fluorescence ≥500); only 20.

Combining one-step Sanger sequencing with phasing probe hybridization for HLA class I typing yields rapid, G-group resolution predicting 99% of unique full length protein sequences.

Background: Sanger-based DNA sequencing of exons 2+3 of HLA class I alleles from a heterozygote frequently results in two or more alternative genotypes. This study was undertaken to reduce the time and effort required to produce a single high resolution HLA genotype.

Materials And Methods: Samples were typed in parallel by Sanger sequencing and oligonucleotide probe hybridization.

Reassessment of T Lymphocytes Crossmatches Results Prediction With Luminex Class I Single Antigen Flow Beads Assay.

Background: In virtual crossmatch (XM) strategies, a correct anticipation of XM results is required for appropriately allocating organs. We reassessed the ability to predict T lymphocyte flow cytometry and complement dependent cytotoxicity XM results with the mean fluorescence intensity (MFI) in Luminex class I single antigen flow beads (SAFB) assay, after correction of complement interference and exclusion of antidenatured HLA antibodies.

Methods: Among 432 XM with T lymphocytes (T-XM), 407 were analyzed after exclusion of antidenatured HLA antibodies.

Evaluation of the iBeads assay as a tool for identifying class I HLA antibodies.

In addition to antibodies targeting native class I human leukocyte antigens (HLA), the single antigen flow beads assay (SAFB) detects antibodies recognizing denatured forms (anti-dHLA). Acid treated SAFB and the modified SAFB reagent named iBeads are expected to distinguish anti-native (anti-nHLA) from anti-dHLA. Sera from 280 class I HLA-sensitized SAFB-positive kidney transplant candidates were retested with acid-treated SAFB and iBeads.

Denatured class I human leukocyte antigen antibodies in sensitized kidney recipients: prevalence, relevance, and impact on organ allocation.

Background: Single antigen flow beads assays may overestimate sensitization because of the detection of supposedly irrelevant antibodies recognizing denatured class I human leukocyte antigens (HLAs).

Methods: Sera of 323 HLA-sensitized kidney transplant candidates positive with a class I HLA single antigen flow beads assay were retested after acid treatment of the beads. Denatured HLA antibodies were identified according to ratio between the measured fluorescence intensity for treated and nontreated beads.

Transcriptional and post-transcriptional processes regulate gene expression in oxygen-deprived roots of maize.

To investigate the regulation of gene expression in maize ( Zea mays L.) in response to oxygen deprivation (flooding), we quantitated run-on transcription in isolated nuclei, steady-state mRNA accumulation and mRNA loading with ribosomes for seven genes that encode proteins synthesized predominantly in oxygen-deprived roots (anaerobic polypeptides) and seven genes that encode proteins synthesized in aerobic roots (aerobic polypeptides). Run-on transcription of anaerobic polypeptide genes was induced in response to oxygen deprivation and run-on transcription of the aerobic polypeptide genes continued during the stress treatment.