Increased natural killer cell subsets with inhibitory cytokines and inhibitory surface receptors in patients with recurrent miscarriage and decreased or normal subsets in kidney transplant recipients late post-transplant.

Patients with recurrent miscarriage (RM) show up-regulated cytotoxic natural killer (NK) cells that are suspected to play a causal role in abortion. In the present study, we investigated counter-regulating inhibitory mechanisms and compared the results in RM patients with those of healthy controls (HC), patients with end-stage renal disease (ESRD) and kidney transplant recipients late post-transplant (TX). NK, NK T and T cell subsets were analysed in the peripheral blood of 31 RM, 14 female ESRD and nine female TX patients as well as 21 female HC using eight-colour fluorescence flow cytometry. Compared with HC, RM patients showed significantly higher absolute numbers of CD56+ NK cells co-expressing the phenotype interferon (IFN)-γR+ , IL-4+ , transforming growth factor (TGF)-ß+ , IL-4+ human leucocyte antigen D-related (HLA-DR)+ , TGF-ß+ HLA-DR+ , IL-4+ TGF-ß+ , IL-4+ TGF-ß- , IFN-γ+ and/or IL-10- IFN-γ+ (all P ≤ 0·01), more IL-17+ CD56bright (P = 0·028) NK cells and more CD56dim CD16+ NK cells co-expressing IFN-γR, IFN-γ, IL-4 and/or TGF-ß (all P ≤ 0·01). When the same cell subsets were analysed in ESRD or TX patients, cytokine-producing NK cell subsets were not significantly different from those of HC. RM patients showed significantly higher absolute numbers of CD158a+ , CD158b+ , CD158a- CD158e+ (all P < 0·05), NKG2D+ NKG2A+ , NKG2D + NKG2A- , NKG2D+ and/or NKG2A+ (all P ≤ 0·01) CD56+ NK cells and higher CD158a+ , CD158b+ (all P < 0·05), NKG2D+ and/or NKG2A+ (all P < 0·01) CD56dim+ CD16+ NK cells than HC. In contrast, ESRD patients had normal and TX recipients had lower CD158a+ and NKG2D+ NKG2A- CD56+ NK cells and lower CD158a+ CD56dim+ CD16+ NK cells (all P < 0·05) than HC. RM patients have abnormally high circulating NK cells expressing inhibitory cytokines and inhibitory surface receptors which might contribute to the pathogenesis of RM.

Association of pre- and early post-transplant serum amino acids and metabolites of amino acids and liver transplant outcome.

The aim of the present study was to investigate association of serum amino (AA) acids and metabolites of AAs with post-transplant outcome in liver transplant recipients. Eighty-nine patients with end-stage liver diseases and available pre- and early post-transplant serum were characterised as patients with (GI) and without one-year mortality (GII) and patients with and without early graft dysfunction (EAD). A panel of pre- and early post-transplant serum levels of AAs and early and metabolites of tryptophan were measured using tandem mass spectrometry. Patient groups had significantly higher pre-transplant serum levels of phenylalanine, tryptophan, and tryptophan metabolites than healthy controls (for all p<0.001). Pre-transplant serum levels of all these parameters were significantly higher in GI than in GII (for all p<0.001). GI had a higher MELD score and re-transplantation number than GII (p≤0.005 for both investigations). Serum bilirubin on day 5 and serum phenylalanine on day 10 post-transplant were associated parameters of mortality, whereas day 1post-transplant phenylalanine and kynurenine and female gender were associated parameters of EAD. Our results indicate that pre- and early post-transplant levels of phenylalanine, tryptophan and metabolites of tryptophan are increased in patients and are associated with EAD and one-year mortality in liver transplant recipients.

Assessing the impact of FoxP3 and Vav1 gene polymorphisms on kidney allograft survival.

FoxP3 and Vav1 are known to be involved in the development of regulatory T cells. Two polymorphic sites in the FoxP3 promoter (rs3761548 and a (GT) n -dinucleotide repeat) and 2 single nucleotide polymorphisms in intron 1 of the Vav1 gene (rs2546133 and rs2617822) have been shown to correlate with gene expression levels. We investigated a potential impact of FoxP3 and Vav1 genetic variants on kidney allograft failure using samples and data of the Collaborative Transplant Study. A cohort of 384 kidney transplant patients was tested. We found no significant association of FoxP3 promoter rs3761548 or (GT) n repeat length with presumed immunological graft failure. The genotype frequencies of Vav1 intron polymorphisms did not significantly differ between patients with graft failure and matched controls.

Association of peripheral NK cell counts with Helios+ IFN-γ- Tregs in patients with good long-term renal allograft function.

Little is known about a possible interaction of natural killer (NK) cells with regulatory T cells (Treg ) in long-term stable kidney transplant recipients. Absolute counts of lymphocyte and Treg subsets were studied in whole blood samples of 136 long-term stable renal transplant recipients and 52 healthy controls using eight-colour fluorescence flow cytometry. Patients were 1946 ± 2201 days (153-10 268 days) post-transplant and showed a serum creatinine of 1·7 ± 0·7 mg/dl. Renal transplant recipients investigated > 1·5 years post-transplant showed higher total NK cell counts than recipients studied < 1·5 years after transplantation (P = 0·006). High NK cells were associated with high glomerular filtration rate (P = 0·002) and low serum creatinine (P = 0·005). Interestingly, high NK cells were associated with high CD4+ CD25+ CD127- forkhead box protein 3 (FoxP3+ ) Treg that co-express the phenotype Helios+ interferon (IFN)-γ- and appear to have stable FoxP3 expression and originate from the thymus. Furthermore, high total NK cells were associated with Treg that co-express the phenotypes interleukin (IL)-10- transforming growth factor (TGF)-ß+ (P = 0·013), CD183+ CD62L- (P = 0·003), CD183+ CD62+ (P = 0·001), CD183- CD62L+ (P = 0·002), CD252- CD152+ (P < 0·001), CD28+ human leucocyte antigen D-related (HLA-DR- ) (P = 0·002), CD28+ HLA-DR+ (P < 0·001), CD95+ CD178- (P < 0·001) and CD279- CD152+ (P < 0·001), suggesting that these activated Treg home in peripheral tissues and suppress effector cells via TGF-ß and cytotoxic T lymphocyte-associated protein 4 (CTLA-4). The higher numbers of NK and Treg cell counts in patients with long-term good allograft function and the statistical association of these two lymphocyte subsets with each other suggest a direct or indirect (via DC) interaction of these cell subpopulations that contributes to good long-term allograft acceptance. Moreover, we speculate that regulatory NK cells are formed late post-transplant that are able to inhibit graft-reactive effector cells.

Pre-transplant soluble CD30 in combination with total DSA but not pre-transplant C1q-DSA predicts antibody-mediated graft loss in presensitized high-risk kidney transplant recipients.

Presensitized kidney transplant recipients are at high-risk for early antibody-mediated rejection. We studied the impact of pre- and post-transplant donor-specific human leukocyte antigen (HLA) antibodies (DSA) and T-cell-activation on the occurrence of antibody-mediated rejection episodes (AMR) and graft loss (AMR-GL) in a unique cohort of 80 desensitized high-risk kidney transplant recipients. Patients with pre-transplant DSA demonstrated more AMR episodes than patients without DSA, but did not show a significantly increased rate of AMR-GL. The rates of AMR and AMR-GL were not significantly increased in patients with complement split product (C1q)-binding pre-transplant DSA. Pre-transplant C1q-DSA became undetectable post-transplant in 11 of 13 (85%) patients; 2 (18%) of these 11 patients showed AMR but no AMR-GL. In contrast, the post-transplant presence of C1q-DSA was associated with significantly higher rates of AMR (86 vs 33 vs 0%; P < 0.001) and AMR-GL (86 vs 0 vs 0%; log-rank P < 0.001) compared with post-transplant DSA without C1q-binding or the absence of DSA. Patients with both pre-transplant DSA and evidence of pre-transplant T-cell-activation as indicated by soluble CD30-positivity showed a significantly increased risk for AMR-GL [HR = 11.1, 95% confidence interval (CI) = 1.68-73.4; log-rank P = 0.013]. In these high-risk patients, AMR-GL was associated with total DSA in combination with T-cell-activation pre-transplant, and de novo or persistent C1q-binding DSA post-transplant.

Patients with idiopathic recurrent miscarriage show higher levels of DR+ activated T-cells that are less responsive to mitogens.

In 50% of recurrent miscarriages (RM) the cause remains unknown and standardized immunological diagnosis and treatment of idiopathic RM (iRM) is yet not established. In this prospective case-control study, out of 220 RM patients screened, 97 iRM patients were identified and compared to 26 healthy controls without a previous pregnancy or blood transfusion in order to identify deregulated immunological parameters. Blood levels of lymphocyte subpopulations, cytokines and neopterin were determined by FACS, ELISA, and Luminex technique. Lymphocyte function was studied by in-vitro lympocyte proliferation tests. As compared to controls, patients had significantly higher proportions of activated CD3+DR+, CD4+DR+ and CD8+DR+ lymphocytes, elevated levels of neopterin and a lower in-vitro proliferation of lymphocytes (all p<0.05). Within the iRM patients higher proportions of CD3+DR+ T-lymphocytes correlated with higher proportions and absolute numbers of CD4+DR+ and CD8+DR+ T-lymphocytes and lower CD16+CD56+ NK-cells. Further, it was associated with lower absolute numbers of CD19+ B-lymphocytes, CD3+CD25+ T-lymphocytes and CD45+ total lymphocytes (all p<0.05). In addition we found decreased in-vitro lymphocyte proliferation in iRM patients with high CD3+DR+ T-lymphocytes (p<0.05). In summary patients with iRM showed increased activated T-cells that are less responsive to mitogens in-vitro. The inverse relationship of increased DR but decreased CD25 expression on CD3+ T-cells and the decreased in-vitro proliferation characterize an immunological disorder with similarities to T-cell exhaustion in patients with HIV and cancer. These abnormalities potentially contribute to the pathogenesis of iRM and might be a target for future immunomodulatory therapies.

Serum levels of chemokines CCL4 and CCL5 in cirrhotic patients indicate the presence of hepatocellular carcinoma.

BACKGROUND: Most hepatocellular carcinomas (HCCs) are diagnosed at an advanced stage. The prognostic value of serum tumour markers alpha-fetoprotein (AFP) and des-gamma-carboxy prothrombin (DCP) is limited. The aim of our study is to evaluate the diagnostic value of serum growth factors, apoptotic and inflammatory mediators of cirrhotic patients with and without HCC. METHODS: Serum samples were collected from cirrhotic potential liver transplant patients (LTx) with (n=61) and without HCC (n=78) as well as from healthy controls (HCs; n=39). Serum concentrations of CRP, neopterin and IL-6 as markers of inflammation and thrombopoietin (TPO), GCSF, FGF basic and VEGF, HMGB1, CK-18 (M65) and CK18 fragment (M30) and a panel of proinflammatory chemokines (CCL2, CCL3, CCL4, CCL5, CXCL5 and IL-8) were measured. Chi square, Fisher exact, Mann-Whitney U-tests, ROC curve analysis and forward stepwise logistic regression analyses were applied. RESULTS: Patients with HCC had higher serum TPO and chemokines (P<0.001 for TPO, CCL4, CCL5 and CXCL5) and lower CCL2 (P=0.008) levels than cirrhotic patients without HCC. Multivariate forward stepwise regression analysis for significant parameters showed that among the studied parameters CCL4 and CCL5 (P=0.001) are diagnostic markers of HCC. Serum levels of TPO and chemokines were lower, whereas M30 was significantly higher in cirrhotic patients than in HCs. CONCLUSIONS: High serum levels of inflammatory chemokines such as CCL4 and CCL5 in the serum of cirrhotic patients indicate the presence of HCC.

Complement C5a receptor gene 450 C/T polymorphism in renal transplant recipients: association of the CT genotype with graft outcome.

Complement-mediated humoral rejection has become the main focus of research in organ transplantation. The aim of this study was to investigate the possible association of the complement C5aR gene 450 C/T polymorphism in antibody-mediated renal allograft rejection. This polymorphism was investigated in 290 first deceased donor kidney graft recipients with well functioning grafts and no rejection treatment during the first transplant year (WFG), 265 recipients with graft failure within the first transplant year (F), and 187 healthy controls. Frequency of the 450 CT genotype was lower in the total population of 555 kidney recipients (4.7%) than in 187 healthy controls (8.6%), but the difference was not statistically significant (P = 0.065). A significantly higher frequency of CT genotype was found in F patients (CT: 6.8%) when compared to WFG patients (CT: 2.8%, P = 0.027). The CT genotype was also significantly lower in WFG patients than in healthy controls (P = 0.009). Low frequency of the C5aR 450 CT genotype, which apparently is a feature of certain kidney diseases, appears to be associated with good graft outcome in kidney transplantation and might be helpful for identifying recipients who are at low risk for graft rejection.

Characterization of mannose-binding lectin (MBL) variants by allele-specific sequencing of MBL2 and determination of serum MBL protein levels.

Mannose-binding lectin (MBL) is a major component of the lectin pathway of complement activation. High and low MBL levels have been associated with susceptibility and severity of a variety of infectious and autoimmune diseases. Several single-nucleotide polymorphisms (SNPs) in the promoter region and exon 1 of the MBL2 gene are responsible for variations in serum MBL levels. We developed a sequence-based typing method for allele-specific MBL2 genotyping and measured serum MBL protein levels in 24 German blood donors. We identified the common MBL2 haplotypes including five promoter polymorphisms in linkage with the Q allele and correlated serum MBL levels with the respective genotypes. The genotyping method presented here could provide a basis for confirmatory studies in larger cohorts.

Minor H antigen matches and mismatches are equally distributed among recipients with or without complications after HLA identical sibling renal transplantation.

Studies of the effect of minor H antigen mismatching on the outcome of renal transplantation are scarce and concern mainly single center studies. The International Histocompatibility and Immunogenetics Workshops (IHIW) provide a collaborative platform to execute crucial large studies. In collaboration with 16 laboratories of the IHIW, the role of 15 autosomal, 10 Y-chromosome encoded minor H antigens and 3 CD31 polymorphisms, was investigated in relation to the incidence of renal graft rejection and graft loss in 444 human leukocyte antigens (HLA)-identical sibling renal transplantations. Recipient and donor DNA samples were genotyped for the minor H antigens HA-1, HA-2, HA-3, HA-8, HB-1, ACC-1, ACC-2, SP110, PANE1, UGT2B17, C19Orf48, LB-ECGF-1, CTSH, LRH-1, LB-ADIR and HY. The correlation between minor H antigen mismatch and the primary outcome graft rejection or graft loss was statistically analyzed. The incidence of rejection was very low and no correlation was observed between one or more minor H antigen mismatch(es) and a rejection episode (n = 36), of which only eight resulted in graft loss. In summary, in our study cohort of 444 renal transplants, mismatching for neither autosomal nor HY minor H antigens correlate with rejection episodes or with graft loss.

Influence of test technique on sensitization status of patients on the kidney transplant waiting list.

The exquisitely sensitive single antigen bead (SAB) technique was shown to detect human leukocyte antigen (HLA) antibodies in sera of healthy male blood donors. Such false reactions can have an impact on critical decisions, especially with respect to the determination of unacceptable HLA-antigen mismatches in patients awaiting a kidney transplant. We tested pretransplant sera of 534 patients on the kidney waiting list using complement-dependent cytotoxicity (CDC), enzyme-linked immunosorbent assay (ELISA) and SAB in parallel. Evidence of HLA antibodies was obtained in 5% of patients using CDC, 14% using ELISA, and 81% using SAB. Among patients without history of an immunizing event, 77% showed evidence of HLA antibodies in SAB. In contrast 98% of these patients were negative in ELISA and CDC. In patients without an immunizing event, SAB-detected antibodies reacted not always weakly but with mean fluorescence intensity (MFI) values as high as 14 440. High-MFI-value antibodies were found in some of these patients with HLA specificities that are rather common in general population, consideration of which would lead to unjustified exclusion of potential kidney donors. False SAB reactions can be unveiled by testing with additional antibody assays. Denial of donor kidneys to recipients based on HLA-antibody specificities detected exclusively in the SAB assay is not advisable.

Association between steroid dosage and death with a functioning graft after kidney transplantation.

Death with a functioning graft remains a major challenge following kidney transplantation. Steroid dosing may be a modifiable risk factor. Collaborative Transplant Study (CTS) data were analyzed to assess the relationship between long-term steroid dose and death with function during years 2-5 posttransplant in 41 953 adult recipients of a deceased-donor kidney transplant during 1995-2010. Steroid dose at year 1 correlated significantly with death with function overall, and with death due to cardiovascular disease or infection (all p < 0.001). In patients with optimal graft function (serum creatinine <130 µmol/L) and no anti-rejection treatment during (a) year 1 (b) years 1 and 2, these significant associations remained (all p < 0.001). The center-specific incidence of steroid withdrawal during year 2 showed a significant inverse association with death due to cardiovascular disease (p < 0.001) or infection (p < 0.001) overall, and within the subpopulation with good graft function and no rejection during year 1 (p = 0.002 and p < 0.001, respectively). Maintenance steroid dose shows a highly significant association with death with a functioning graft caused by cardiovascular disease or infection during years 2-5 after kidney transplantation, even in patients with good graft outcomes in whom steroid treatment would appear to be unnecessary.

Superiority of AbCross enzyme-linked immunosorbent assay cross-match over the B-cell complement-dependent lymphocytotoxicity cross-match.

BACKGROUND: The AbCross enzyme-linked immunosorbent assay (ELISA) cross-match is a recently introduced solid phase cross-match technique with several technical advantages over the currently available Antibody Monitoring System ELISA cross-match. METHODS: In the present study, we investigated the potential superiority of AbCross over the traditional complement-dependent lymphocytotoxicity (CDC) B-cell cross-match (BXM). Pretransplant sera of 271 kidney transplant recipients who were transplanted at our center between 1998 and 2010 were tested in ELISA screening for the presence of human leukocyte antigen (HLA) antibodies and in AbCross and CDC for antibody reactivity against solubilized donor HLA class I and II antigens and donor B cells, respectively. RESULTS: Patients positive for HLA class I or II antibodies on ELISA screening had a significantly poorer graft outcome 2 years after transplantation than recipients who were negative for HLA antibodies (21% vs 6% graft loss; P = .002). Corresponding with this finding, 37 recipients positive for HLA antibodies in AbCross against donor HLA class I or II antigens had a 2-year post-transplant graft loss rate of 19%, which is significantly higher than the 8% rate in 186 recipients who were negative for both antibody classes in AbCross (P = .043). The 2-year graft loss rate in 34 AbCross positive but BXM negative patients was 21%, compared with 7% in 172 AbCross and BXM negative patients (P = .012) and 9% in 11 AbCross negative but BXM positive patients (P = .39). CONCLUSIONS: Our data indicate that the AbCross ELISA cross-match is superior to the CDC BXM, most likely because it detects antibodies against donor HLA antigens at a higher sensitivity.

Plasticity and overlap of in vitro-induced regulatory T-cell markers in healthy humans.

Induced regulatory T cells (iTreg) are a heterogeneous T-cell subset that is induced during an allo-response and down-regulates the immune response. iTreg are commonly characterized as CD4(+)CD25(high), CD4(+)CD25(high)FoxP3(+), CD4(+)CD25(high)CD127(-), or CD4(+)CD25(high)FoxP3(+)CD127(-) peripheral blood lymphocytes (PBL). In the present study, we investigated the overlap of these 4 phenotypically determined iTreg subsets in normal human individuals. PBL of 8 healthy individuals were incubated for 0 hours (Group 1) or for 16 hours in medium without (Group 2) or with phorbol 12-myristate 13-acetate (PMA)/Ionomycin (Group 3). Thereafter, proportions of PBL with Treg phenotypes were determined using 4-color flow-cytometry. All 4 Treg subsets increased strongly during polyclonal stimulation (P < .001). After stimulation, combining 2 iTreg markers, 24% of stimulated CD4(+) PBL were CD25(high)FoxP3(+), 18% CD25(high)CD127(-), and 61% FoxP3(+)CD127(-). Combining 3 iTreg markers, only 18% of the polyclonally stimulated CD4(+) PBL were CD25(high)FoxP3(+)CD127(-). Importantly, the proportion of FoxP3(+)CD127(-) PBL increased with the quantity of CD25 on stimulated CD4(+) PBL and was highest in CD25(high) PBL (P = .002), emphasizing the relevance of CD25(high) as iTreg marker. Different iTreg phenotypes should not be used interchangeably because they define different iTreg subsets that overlap only in part. CD25(high) is the most relevant iTreg marker. These conclusions should be considered when studies and experiments involving iTreg phenotypes are compared.

Differences in the induction of induced human CD4(+) CD25(+) FoxP3(+) T-regulatory cells and CD3(+) CD8(+) CD28(-) T-suppressor cells subset phenotypes in vitro: comparison of phorbol 12-myristate 13-acetate/ionomycin and phytohemagglutinin stimulation.

CD4(+) CD25(+) FoxP3(+) T-regulatory cells (Treg) and CD3(+) CD8(+) CD28(-) T-suppressor cells (Ts) were shown to have immunosuppressive function in vivo and in vitro. However, the in vitro inducibility of Ts subsets is rather unclear. We investigated the induction of Treg and Ts subsets in peripheral blood mononuclear cells of 5 healthy control individuals during stimulation with phorbol 12-myristate 13-acetate (PMA)/ionomycin or phytohemagglutinin (PHA). Phenotypes were analyzed 0, 4, 8, 16, and 24 hours after initiation of cell culture using 4-color fluorescence flow-cytometry. Number of CD4(+) CD25(+) FoxP3(+) CD127(-) Treg increased during PMA/ionomycin or PHA stimulation (P < .01). CD4(+) CD25(+) FoxP3(+) Treg coexpressed the phenotypes interleukin (IL)-2(-), IL-10(+), and/or transforming growth factor (TGF)-ß(+) after stimulation (all P < .01). Interferon (IFN)-γ production was induced only by PMA/ionomycin (P < .01) but not by PHA (P = NS). IFN-γ-secreting Treg were detectable at 4 hours whereas IL-2(-), IL-10(+) and/or TGF-ß(+) Treg required 16 hours of stimulation. In contrast, CD3(+) CD8(+) CD28(-) Ts phenotypes were not inducible during 24-hour PMA/ionomycin or PHA stimulation (all P = NS). However, Ts coexpressed IL-10 and/or TGF-ß during polyclonal stimulation (all P < .01), whereas the proportion of IL-2(-) Ts remained stable during the cell culture period (P = NS). Similar to Treg, IFN-γ-secreting Ts were detected only during PMA/ionomycin stimulation (P < .01), but not during PHA stimulation (P = NS). We conclude that the proportion of CD3(+) CD8(+) CD28(-) Ts remains stable during polyclonal stimulation. They modify only the cytokine pattern indicating activation of the Ts. In contrast, CD4(+) CD25(+) FoxP3(+) CD127(-) Treg are inducible by PMA/ionomycin and PHA stimulation. IFN-γ- secreting Treg form the first line of immunoregulatory T cells during an initiated immune response followed by IL-2(-), IL-10(+), and/or TGF-ß(+) Treg.

No impact of KIR-ligand mismatch on allograft outcome in HLA-compatible kidney transplantation.

Natural killer (NK) cell function can be modulated by the killer cell immunoglobulin-like receptors (KIR) which interact with human leukocyte antigen (HLA) class I molecules on target cells. KIR-ligand mismatching has recently been shown by van Bergen et al. (American Journal of Transplantation 2011; 11(9): 1959-1964) to be a significant risk factor for long-term graft loss in HLA-A, -B and -DR compatible kidney transplants. To verify this potentially important finding, we performed genotyping of 608 deceased-donor kidney graft recipients and their HLA-A, -B and -DR compatible donors for KIR and HLA, using samples and clinical data provided by the Collaborative Transplant Study. Graft survival of KIR-ligand-matched and -mismatched transplants was compared. We found no impact of KIR-ligand mismatching on 10-year graft survival in HLA-A, -B, -DR compatible kidney transplants. Further analysis did not reveal a significant effect of recipient activating/inhibitory KIR or KIR genotypes on graft survival. Our data do not support the concept that KIR-HLA matching might serve as a tool to improve long-term renal allograft survival.

Ceppellini Lecture 2012: collateral damage from HLA mismatching in kidney transplantation.

Inclusion of human leukocyte antigen (HLA) matching in donor kidney allocation schemes has been based solely on its association with graft survival. Other long-term effects associated with HLA incompatibility are largely unexplored. Data from deceased donor kidney transplants reported to the Collaborative Transplant Study have been analyzed to assess the relation between HLA mismatching and clinical events to 3 years post-transplant, and an overview of these analyses is presented. A significant correlation was observed between the number of mismatches and the need for anti-rejection therapy during the first year post-transplant, which was maintained for HLA-DR and HLA-A + B mismatching separately and at years 2 and 3 post-transplant. The number of HLA-DR mismatches and the number of HLA-A + B mismatches as well as rejection treatment showed significant associations with the dose of maintenance steroids. The cumulative incidences of death with a functioning graft from infection or cardiovascular causes, but not from cancer, were also significantly associated with HLA mismatching. The number of HLA-DR mismatches showed a significant association with the incidence of non-Hodgkin lymphoma and hip fractures. These findings show that the adverse consequences of HLA mismatching on kidney transplants extend beyond an effect on graft survival, and include an increased risk of death with a functioning graft, non-Hodgkin lymphoma and hip fracture.

Association of HLA mismatch with death with a functioning graft after kidney transplantation: a collaborative transplant study report.

HLA mismatches may correlate with risk of death with a functioning graft (DWFG) because of requirement for higher immunosuppression doses and more antirejection therapy. Deceased-donor kidney transplants (n = 177 584) performed 1990-2009 and reported to the Collaborative Transplant Study were analyzed. The incidence of DWFG was found to be 4.8% during year 1 posttransplant and 7.7% during years 2-5 (Kaplan-Meier estimates). Most frequent causes of DWFG were infection, cardiovascular disease and malignancy (32.2%, 30.9% and 3.6% in year 1; 16.4%, 29.6% and 15.9% in years 2-5). HLA-A + B + DR mismatches were significantly associated with DWFG during year 1 (p < 0.001), a correlation that diminished but persisted during years 2-5 (p < 0.001). HLA mismatch was associated with DWFG because of infection (p < 0.001 during year 1, p = 0.043 during years 2-5) or cardiovascular disease (p < 0.001 during year 1, p = 0.030 during years 2-5) but not malignancy. There was also a significant association between HLA mismatch and hospitalization for viral (p < 0.001) or bacterial (p = 0.002) infection. Multivariable analysis showed that mismatches for HLA class II were more strongly associated with both hospitalization and DWFG than mismatches for HLA class I.