Donor-specific antibody and sensitized patients in intestinal transplantation.

Purpose Of Review: It has been well established that antibody to donor HLA pretransplant and the development of anti-human leukocyte antigen (HLA) antibodies posttransplant contribute to inferior graft survival outcomes. This article serves to review the current status of the management of pretransplant sensitized intestinal transplant candidate as well as to review posttransplant care of patients that harbor antidonor HLA antibodies.

Recent Findings: The intestinal transplant candidate oftentimes presents for transplant listing with high levels of anti-HLA antibodies that necessitate a careful preoperative strategy to avoid a donor-recipient pair that would result in a positive crossmatch.

Pre-empting Antibody-Mediated Rejection: A Program of DSA Monitoring and Treatment Can Effectively Prevent Antibody Mediated Rejection.

Antibody-mediated rejection (AMR) remains a problem without a reliable treatment in the care of kidney transplant patients. We proposed and tested a program of screening for donor specific antibodies (DSA) to initiate treatment of patients before AMR was detected and to prevent its occurrence. Starting in April 2012, we stratified patients into high-, medium-, and low-risk groups for the development of DSA and instituted a program of screening for and treatment of these antibodies.

Successful isolated intestinal transplantation in sensitized recipients with the use of virtual crossmatching.

We evaluated virtual crossmatching (VXM) for organ allocation and immunologic risk reduction in sensitized isolated intestinal transplantation recipients. All isolated intestine transplants performed at our institution from 2008 to 2011 were included in this study. Allograft allocation in sensitized recipients was based on the results of a VXM, in which the donor-specific antibody (DSA) was prospectively evaluated with the use of single-antigen assays.

Paired kidney donor exchanges and antibody reduction therapy: novel methods to ameliorate disparate access to living donor kidney transplantation in ethnic minorities.

Background: Currently ethnic minority patients comprise 60% of patients listed for kidney transplantation in the US; however, they receive only 55% of deceased donor renal transplants and 25% of living donor renal transplants. Ethnic disparities in access to kidney transplantation result in increased morbidity and mortality for minority patients with end-stage renal disease. Because these patients remain dialysis dependent for longer durations, they are more prone to the development of HLA antibodies that further delay the possibility of receiving a successful kidney transplant.

Donor transmission of pineoblastoma in a two-yr-old male recipient of a multivisceral transplant: a case report.

Transplant-transmitted malignances are rare but devastating events. Primary brain tumors are the least common among reported donor-derived malignancies. We report a case of donor-transmitted pineoblastoma, a PNET, in a two-yr-old male recipient, who presented with a rapidly growing mass in the right mandible, four months after multiple visceral organ transplantation.

The detection of donor-directed, HLA-specific alloantibodies in recipients of unrelated hematopoietic cell transplantation is predictive of graft failure.

Donor-directed human leukocyte antigen (HLA)-specific allo-antibodies (DSAs) cause graft failure in animal models of hematopoietic stem cell transplantation (HCT). Archived pretransplantation sera from graft failure patients (n = 37) and a matched case-control cohort (n = 78) were tested to evaluate the role of DSAs in unrelated donor HCT. Controls were matched for disease, disease status, graft type, patient age, and transplantation year.

Investigation of the putative immunodominant T cell epitopes in coeliac disease.

Background: Coeliac disease (CD) is an enteropathy mediated by gluten specific T cells which secrete interferon gamma (IFN-gamma) when stimulated by gluten peptides presented by HLA-DQ2 or DQ8 molecules. Residues 62-75 of alpha(2) gliadin have been proposed as the immunodominant epitope in the majority of CD patients. Deamidation by tissue transglutaminase (tTG) of the glutamine (Q) at position 65 to glutamic acid (E) is essential for T cell stimulation.

Coeliac disease: follow-up linkage study provides further support for existence of a susceptibility locus on chromosome 11p11.

Susceptibility to coeliac disease has a strong genetic component. The HLA associations have been well described but it is clear that other genes outside this region must also be involved in disease development. Two previous genome-wide linkage studies using the affected sib pair method produced conflicting results.

A genome-wide family-based linkage study of coeliac disease.

The susceptibility to develop coeliac disease (CD) has a strong genetic component, which is not entirely explained by HLA associations. Two previous genome wide linkage studies have been performed to identify additional loci outside this region. These studies both used a sib-pair design and produced conflicting results.

Gluten-induced nitric oxide and pro-inflammatory cytokine release by cultured coeliac small intestinal biopsies.

Objectives: To determine whether there was increased nitric oxide (NO) production from coeliac small intestinal biopsies cultured in vitro with gluten and whether the inhibition of NO production could prevent gluten-induced enterotoxicity. The relationship between NO production with the pro-inflammatory cytokines interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) was evaluated.

Design: Small intestinal biopsies from ten patients with treated coeliac disease and six controls were studied.

Family linkage study of the T-cell receptor genes in coeliac disease.

Background: The susceptibility to coeliac disease is genetically determined by possession of certain HLA DQ alleles, together with a one or more non-HLA genes. The central role of the T-cell receptor in disease pathogenesis makes the T-cell receptor genes strong candidates as disease susceptibility genes, and previous studies had provided equivocal ambiguous results.

Methods: A pedigree based genetic linkage study was used to determine if any of the T-cell receptor genes have a role in the genetic aetiology of coeliac disease.

Measurement of gluten using a monoclonal antibody to a coeliac toxic peptide of A-gliadin.

Background: Future European Community regulations will require a sensitive and specific assay for measurement of coeliac toxic gluten proteins in foods marketed as gluten-free. To avoid spurious cross reactions with non-toxic proteins, specific antibodies and target antigens are required. A synthetic 19 amino acid peptide of A gliadin has been shown to cause deterioration in the morphology of small intestinal biopsy specimens of coeliac patients in remission.

The detection and localization of inducible nitric oxide synthase production in the small intestine of patients with coeliac disease.

Objectives: To investigate whether there are increased numbers of inducible nitric oxide synthase (iNOS) containing cells in the small intestine of patients with coeliac disease and the localization of nitric oxide synthase production.

Design: Small intestinal biopsy specimens from patients with coeliac disease (11 untreated, 10 treated) and nine disease controls were studied.

Methods: Histochemical staining of sections for NADPH-diaphorase activity was performed, which gives an indication of NOS activity.

Binding of gluten-derived peptides to the HLA-DQ2 (alpha1*0501, beta1*0201) molecule, assessed in a cellular assay.

The nature of the immunopathogenic relationship underlying the very strong association of coeliac disease (CD) to the HLA-DQ (A1*0501, B1*0201) genotype is not known, but probably relates to binding of gluten-derived epitopes to the HLA-DQ (alpha1*0501, beta1*0201) heterodimer (DQ2). These epitopes have not yet been defined. In this study we have tested the binding of various gluten-derived peptides to DQ2 in a cellular assay using Epstein-Barr virus (EBV)-transformed B lymphocytes and murine fibroblast transfectants.

Detection and characterisation of anti-endomysial antibody in coeliac disease using human umbilical cord.

Objectives: To verify the effectiveness of human umbilical cord (HUC) in the detection of anti-endomysial antibodies (AEA) in coeliac disease and to characterize further these antibodies by studying tissue adsorption characteristics and antibody inhibition studies.

Methods: AEA were detected on HUC and primate oesophagus in a blind study, using sera from 46 patients with untreated coeliac disease and 108 controls. Tissue adsorption studies were performed using homogenized tissue from rodent liver, HUC, primate oesophagus and human liver.

Analysis of interleukin-4 and interleukin-10 and their association with the lymphocytic infiltrate in the small intestine of patients with coeliac disease.

Background: Concentrations of pro-inflammatory cytokines are raised in the small intestine of patients with coeliac disease after ingestion of gluten but there are equivalent data on interleukin-4 (IL-4) and interleukin-10 (IL-10) producing cells. These cytokines are known to exert important regulatory effects on pro-inflammatory cytokine production from lymphocytes and macrophages.

Aims: To investigate whether there is a primary deficiency of IL-4 and IL-10 producing cells and their site of production in the small intestine of patients with coeliac disease in relation to the changes in inflammatory cell infiltrate.

Diverse usage of human T-cell receptor gene segments in HLA-DR1 allospecific T-cell clones.

T-cell recognition of alloantigen involves both the MHC molecule and its associated peptide ligand. To understand the relationship between the specificity of alloantigen recognition and the structure of TCR molecules, we have investigated TCR gene utilization by sequencing TCR genes from well-defined allospecific T-lymphocyte clones. Alloreactive TLC consisted of a panel of clones primed to recognize DR1-related alloantigens.

The relative importance of individual DR binding motif positions as defined by peptide anchor analysis of influenza hemagglutinin peptide 306-318 and human myelin basic protein peptide 152-165 binding to several DR molecules: definition of a common extended DR binding motif.

Definition of peptide binding motifs for DR molecules has proven difficult as the peptides that bind to a DR molecule have shown extensive variability at putative motif positions. Recent studies suggest that specific peptide anchor residues (motif positions) and specific DR residues can differ in importance for peptide binding to a DR molecule. To assess further the relevance of individual peptide anchor residues, the binding of serial alanine-substituted analogs of influenza virus hemagglutinin (HA) 306-318 and human myelin basic protein (MBP) 152-165 to a panel of transfected wild-type DR molecules was examined.

Different requirements of ICAM-1/LFA-1 adhesion in allorecognition and self-restricted antigen recognition by class II-specific T cell clones.

We have analyzed the influence of non-antigen-specific interactions between ICAM-1 and LFA-1 in target recognition by allospecific and antigen-specific T cells at the clonal level, using human and mouse fibroblasts transfected with HLA-DR1 or DR2 with or without co-expression of ICAM-1, as antigen-presenting cells. The results show a great heterogeneity in the requirements for ICAM-1/LFA-1 interactions for antigen-specific and alloreactive T cell responses and this requirement may depend on the avidity of any particular interaction. The data also show that for most alloreactive clones, ICAM-1/LFA-1 adhesion is not sufficient to facilitate efficient T cell recognition of its target molecule.

HLA-A*8001 is a member of a newly discovered ancient family of HLA-A alleles.

A member of a new HLA-A locus family, HLA-A*8001, has been characterized from 3 African-American individuals expressing a unique HLA-A serologic specificity. The HLA-A*8001 sequence is most closely related to alleles of the HLA-A1/3/11 family, although it also contains residues characteristic of the HLA-A2/28, -A9, -A10, and -A19 families. More importantly, the HLA-A*8001 sequence contains four unique nonsynonymous (amino acid replacing) nucleotide substitutions absent from all other primate A locus alleles.

Nonrandom T cell receptor usage in the allorecognition of HLA-DR1 microvariation.

Microvariation within the DR1 Ag family has created two DR molecules which differ only at beta-chain residues 85 (Val/Ala) and 86 (Gly/Val). TCR utilized by human alloproliferative T lymphocyte clones which can distinguish between these microvariants have been characterized by cDNA sequencing. The alpha- and beta-chain cDNA utilize a diverse set of variable (V) gene segments although the same V segment may be used by different individuals suggesting that V segment usage by the alloreactive T lymphocyte clones is nonrandom.

Peptide-induced nonresponsiveness of HLA-DP restricted human T cells reactive with Dermatophagoides spp. (house dust mite).

The activation of CD4+ T lymphocytes, which play a central role in allergic inflammation, depends on the recognition of allergen-derived peptides in association with major histocompatibility complex class II gene products. In this report we demonstrate, at a clonal level, that a component of the T-cell repertoire reactive with Dermatophagoides spp. (house dust mite) in atopic individuals, is restricted by HLA-DP class II molecules.

Efficient cDNA expression vectors for stable and transient expression of HLA-DR in transfected fibroblast and lymphoid cells.

cDNA expression vectors with several useful features were constructed. First, the long terminal repeat of Rous sarcoma virus was used as a promoter to obtain high levels of expression in various cells of human and mouse origin. Second, cis-linked expression units that confer resistance either to mycophenolic acid or the neomycin analog G418 were inserted to facitate the isolation of transfected cells expressing the cDNA of interest.

Polymorphic HLA-DR7 beta 1 chain residues that are involved in T cell allorecognition.

The contributions to allorecognition of polymorphic amino acids in the HLA-DR7 beta 1 chain were analyzed by using mutant DR7 beta 1 chains with single amino acid substitutions at position 4, 11, 13, 25, 30, 37, 57, 60, 67, 70, 71, 74, or 78. Transfectants expressing mutant DR7 molecules were used as stimulators for six DR7-alloreactive T cell clones. The majority of the substitutions had profound effects on the ability of the DR7 molecule to stimulate one or more T cell clones.