Background.HLA-specific memory B cells may contribute to the serum HLA antibody pool upon antigen reexposure. The aim of this pilot study was to investigate the presence of concurrent donor... Show moreBackground.HLA-specific memory B cells may contribute to the serum HLA antibody pool upon antigen reexposure. The aim of this pilot study was to investigate the presence of concurrent donor-specific memory B cell-derived HLA antibodies (DSA-M) in renal allograft recipients with pretransplant donor-specific HLA antibodies (DSA) and its association with occurrence of antibody-mediated rejection (AMR) using a recently developed method.Methods.Twenty patients with Luminex single antigen bead (SAB) assay-defined DSA but negative complement-dependent cytotoxicity crossmatches were enrolled. Plasma samples and peripheral blood mononuclear cells were collected at 3 timepoints (pretransplant, mo 6, mo 12). We analyzed IgG-purified and concentrated culture supernatants from polyclonally activated peripheral blood mononuclear cells using SAB assays and compared HLA antibody profiles with same day plasma results.Results.Plasma SAB analysis revealed 35 DSA in 20 patients pretransplant. DSA-M were detected in 9 of 20 (45%) patients and for 10 of 35 specificities (29%). While median mean fluorescence intensity values of DSA with concurrent DSA-M (5877) were higher than those of DSA without DSA-M (1476), 3 of 6 patients with AMR and low mean fluorescence intensity DSA (<3000) had DSA-M. Overall, pretransplant DSA/DSA-M-pos allograft recipients showed a higher incidence of biopsy-proven (sub)clinical AMR (P = 0.032) and a higher extent (g >= 1 + ptc >= 1) of microvascular inflammation (67% vs 9%, P = 0.02). In 17 patients (28 DSA) with posttransplant analyses, persisting DSA posttransplant had more often DSA-M (6/12; 50%) than nonpersisting DSA (2/16; 13%).Conclusions.Assessment of DSA-M might be a novel tool to supplement serum HLA antibody analysis for pretransplant risk stratification in patients with DSA. Show less
In renal transplantation, polymorphic amino acids on mismatched donor HLA molecules can lead to the induction of de novo donor-specific antibodies (DSA), which are associated with inferior graft... Show moreIn renal transplantation, polymorphic amino acids on mismatched donor HLA molecules can lead to the induction of de novo donor-specific antibodies (DSA), which are associated with inferior graft survival. To ultimately prevent de novo DSA formation without unnecessarily precluding transplants it is essential to define which polymorphic amino acid mismatches can actually induce an antibody response. To facilitate this, we developed a user-friendly software program that establishes HLA class I and class II compatibility between donor and recipient on the amino acid level. HLA epitope mismatch algorithm (HLA-EMMA) is a software program that compares simultaneously the HLA class I and class II amino acid sequences of the donor with the HLA amino acid sequences of the recipient and determines the polymorphic solvent accessible amino acid mismatches that are likely to be accessible to B cell receptors. Analysis can be performed for a large number of donor-recipient pairs at once. As proof of principle, a previously described study cohort of 191 lymphocyte immunotherapy recipients was analysed with HLA-EMMA and showed a higher frequency of DSA formation with higher number of solvent accessible amino acids mismatches. Overall, HLA-EMMA can be used to analyse compatibility on amino acid level between donor and recipient HLA class I and class II simultaneously for large cohorts to ultimately determine the most immunogenic amino acid mismatches. Show less
The future of HLA matching in solid organ transplantation lies in epitope matching. The article by Sapir-Pichhadze et al. provides indirect evidence that there is a difference in immunogenicity... Show moreThe future of HLA matching in solid organ transplantation lies in epitope matching. The article by Sapir-Pichhadze et al. provides indirect evidence that there is a difference in immunogenicity between antibody-verified versus non-verified eplets. However, this difference was less clear for HLA class II, showing the need for additional efforts to identify truly immunogenic HLA class II epitope mismatches. Show less
In oocyte donation (OD) pregnancy, a fetus can be completely allogeneic to the recipient. Consequently, the maternal immune system has to cope with greater immunogenetic dissimilarity compared to... Show moreIn oocyte donation (OD) pregnancy, a fetus can be completely allogeneic to the recipient. Consequently, the maternal immune system has to cope with greater immunogenetic dissimilarity compared to naturally conceived pregnancy. Previously, we showed an association between successful OD pregnancy and lower immunogenetic dissimilarity, reflected by the number of fetal-maternal Human Leukocyte Antigen (HLA) mismatches, than expected by chance. In this study we aimed to determine whether the development of preeclampsia in OD pregnancies is related to the number of fetal-maternal HLA mismatches.A retrospective, nested case-control study was performed within a cohort of 76 singleton OD pregnancies. Maternal and fetal umbilical cord blood was typed for HLA-A, -B, -C, -DR and -DQ, and the number of fetal-maternal HLA mismatches was calculated. In addition, the incidence of child-specific HLA antibodies was determined.13 pregnancies were complicated by preeclampsia. To demonstrate an influence of HLA mismatches on the development of preeclampsia, a univariate logistic regression analysis was performed adjusted for maternal age and socio-economic status. A significant association between the number of fetal-maternal HLA class II mismatches and the development of preeclampsia was observed (OR = 3.8, 95 % CI: 1.6-9.0; p = 0.003). This association was not linked to the development of HLA class II antibodies.According to our findings, an increased number of HLA class II mismatches is a risk factor for the development of preeclampsia in OD pregnancies. The effect of HLA class II mismatches might be explained by the induction of a cellular rather than a humoral immune response. Show less
Craenmehr, M.H.C.; Keur, C. van der; Anholts, J.D.H.; Kapsenberg, J.M.; Westerlaken, L.A. van der; Kooten, C. van; ... ; Eikmans, M. 2020
Dendritic cells (DCs) are key in shaping immune responses and are recruited to the human cervix after coitus by seminal plasma (SP). SP has been shown to skew the differentiation of monocyte... Show moreDendritic cells (DCs) are key in shaping immune responses and are recruited to the human cervix after coitus by seminal plasma (SP). SP has been shown to skew the differentiation of monocyte-derived DCs towards an anti-inflammatory profile when cultured in medium containing fetal calf serum (FCS). Here, we confirmed that SP skewed DCs cultured in fetal bovine serum (FBS) towards a tolerogenic profile. To create a setting more similar to the in vivo situations in humans, we tested the immune regulatory effect of SP on DCs in cell cultures containing human serum (HS). SP-DCs cultured in HS did show increased CD14 and decreased CD1a, indicating an inhibited maturation phenotype. Gene expression of TGF-beta and IL-10 and IL-10 protein expression were elevated in LPS-activated SP-DCs, whereas IL-12p70 protein levels were decreased compared to LPS-activated control DCs. In contrast to FBS culture conditions, in the presence of HS co-cultures of SP-DCs with allogeneic peripheral blood mononuclear cells (PBMCs) did not result in decreased T cell proliferation and inflammatory cytokine production. Thus, under HS culture conditions SP can skew the differentiation of monocyte-derived DCs phenotypically towards alternatively activated DCs, but this immune regulatory phenotype is functionally less pronounced compared to SP-treated DCs cultured in FBS containing medium. These findings highlight the importance of the source of the serum that is used in SP treated cell cultures in vitro. Show less
In renal transplantation, polymorphic amino acids on mismatched donor HLA molecules can lead to the induction of de novo donor-specific antibodies (DSA), which are associated with inferior graft... Show moreIn renal transplantation, polymorphic amino acids on mismatched donor HLA molecules can lead to the induction of de novo donor-specific antibodies (DSA), which are associated with inferior graft survival. To ultimately prevent de novo DSA formation without unnecessarily precluding transplants it is essential to define which polymorphic amino acid mismatches can actually induce an antibody response. To facilitate this, we developed a user-friendly software program that establishes HLA class I and class II compatibility between donor and recipient on the amino acid level. HLA epitope mismatch algorithm (HLA-EMMA) is a software program that compares simultaneously the HLA class I and class II amino acid sequences of the donor with the HLA amino acid sequences of the recipient and determines the polymorphic solvent accessible amino acid mismatches that are likely to be accessible to B cell receptors. Analysis can be performed for a large number of donor-recipient pairs at once. As proof of principle, a previously described study cohort of 191 lymphocyte immunotherapy recipients was analysed with HLA-EMMA and showed a higher frequency of DSA formation with higher number of solvent accessible amino acids mismatches. Overall, HLA-EMMA can be used to analyse compatibility on amino acid level between donor and recipient HLA class I and class II simultaneously for large cohorts to ultimately determine the most immunogenic amino acid mismatches. Show less
Recognition of non-self structures on donor cells represents the main immunological barrier in solid organ transplantation. The human leukocyte antigens (HLA) are considered the most important non... Show moreRecognition of non-self structures on donor cells represents the main immunological barrier in solid organ transplantation. The human leukocyte antigens (HLA) are considered the most important non-self (allo)antigens in transplantation. Long-term graft attrition is mainly caused by the formation of alloreactive antibodies that are directed against non-self structures (i.e., epitopes) on cell surface proteins. Recently published data provided evidence for a similar importance of non-HLA mismatches between donors and recipients in acute rejection as well as long-term kidney allograft survival. These data suggest a broader concept of immunological non-self that goes beyond HLA incompatibility and expands the current concept of polymorphic non-self epitopes on cell surface molecules from HLA to non-HLA targets. Amino acid substitutions caused by single nucleotide variants in protein-coding genes or complete loss of gene expression represent the basis for polymorphic residues in both HLA and non-HLA molecules. To better understand these novel insights in non-HLA alloimmunity, we will first review basic principles of the alloimmune response with a focus on the HLA epitope concept in donor-specific antibody formation before discussing key publications on non-HLA antibodies. Show less
Abacavir administration is associated with drug-induced hypersensitivity reactions in HIV+ individuals expressing the HLA-B*57:01 allele. However, the immunological effects of abacavir... Show moreAbacavir administration is associated with drug-induced hypersensitivity reactions in HIV+ individuals expressing the HLA-B*57:01 allele. However, the immunological effects of abacavir administration in an HLA-B57 mismatched transplantation setting have not been studied. We hypothesized that abacavir exposure could induce de novo HLA-B57-specific allorecognition. HIV-specific CD8 T cell clones were generated from HIV+ individuals, using single cell sorting based on HIV peptide/HLA tetramer staining. The T cell clones were assayed for alloreactivity against a panel of single HLA-expressing cell lines, in the presence or absence of abacavir. Cytokine assay, CD137 upregulation, and cytotoxicity were used as readout. Abacavir exposure can induce de novo HLA-B57 allorecognition by HIV-specific T cells. A HIV Gag RK9/HLA-A3-specific T cell did exhibit interferon-gamma production, CD137 upregulation, and cytolytic effector function against allogeneic HLA-B57, but only in the presence of abacavir. Allorecognition was specific to the virus specificity, HLA restriction, and T cell receptor TRBV use of the T cell. We provide proof-of-principle evidence that administration of a drug could induce specific allorecognition of mismatched HLA molecules in the transplant setting. We suggest that HIV-seropositive recipients of an HLA-B57 mismatched graft should not receive abacavir until further studies are completed. Show less
Tissue resident lymphocytes are present within many organs, and are presumably transferred at transplantation, but their impact on host immunity is unclear. Here, we examine whether transferred... Show moreTissue resident lymphocytes are present within many organs, and are presumably transferred at transplantation, but their impact on host immunity is unclear. Here, we examine whether transferred donor natural regulatory CD4 T cells (nT-regs) inhibit host alloimmunity and prolong allograft survival. Transfer of donor-strain lymphocytes was first assessed by identifying circulating donor-derived CD4 T cells in 21 consecutive human lung transplant recipients, with 3 patterns of chimerism apparent: transient, intermediate, and persistent (detectable for up to 6 weeks, 6 months, and beyond 1 year, respectively). The potential for transfer of donor nT-regs was then confirmed by analysis of leukocyte filters recovered from ex vivo normothermic perfusion circuits of human kidneys retrieved for transplantation. Finally, in a murine model of cardiac allograft vasculopathy, depletion of donor CD4 nT-regs before organ recovery resulted in markedly accelerated heart allograft rejection and augmented host effector antibody responses. Conversely, adoptive transfer or purified donorstrain nT-regs inhibited host humoral immunity and prolonged allograft survival, and more effectively so than following administration of recipient nT-regs. In summary, following transplantation, passenger donor-strain nT-regs can inhibit host adaptive immune responses and prolong allograft survival. Isolated donor-derived nT-regs may hold potential as a cellular therapy to improve transplant outcomes. Show less
