A study of cytokine gene polymorphisms and protein secretion in renal transplantation

Although there is evidence that cytokine gene polymorphisms are associated with varying quantities of cytokine protein production, the exact role of these polymorphisms in allograft rejection remains unclear. In a previous study, we demonstrated a significant association between high IL-10 secretion in mixed lymphocyte culture (MLC), together with HLA mismatching for at least 4-6 antigens, with the occurrence of acute rejection following renal transplantation. We, therefore, wished to ascertain whether cytokine gene polymorphisms are associated with varying levels of protein secretion and/or allograft rejection in the same group of patients. Cytokine protein secretion in MLC for IL-4, IL-6, IL-10 and IFN-gamma was measured by ELISA in 49 patient-donor pairs. Protein secretion for the above cytokines was also measured in phytohaemagglutinin (PHA) stimulated cultures in 30 normal controls. In both patient and control groups, single nucleotide polymorphism analysis for IL-4 G(-590)T, IL-6 G(-174)C, IL-10 G(-1082)A, IL-10 C(-819)T, IL-10 C(-592)A, TNF-alpha G(-308)A and microsatellite analysis for IFNG (CA repeat) was performed. No correlation was found between cytokine gene polymorphisms and cytokine protein secretion in either mitogen stimulated cultures (control group) or MLC (patient group). In addition, no correlation was demonstrated between cytokine gene polymorphisms and renal allograft rejection.     

A study of cytokine protein secretion, frequencies of cytokine expressing cells and IFN-G gene polymorphisms in normal individuals

BACKGROUND: Cytokines are major regulators of immune responses, and there is evidence that they play a role in allograft rejection. Before embarking on a detailed study of pretransplant cytokine profiles in renal allograft recipients, we wished to investigate variations in cytokine protein secretion, numbers of cytokine expressing T cells, and cytokine gene polymorphisms in normal volunteers. METHODS: Twenty normal healthy volunteers were studied. Cytokine protein secretion [interleukin- (IL) 2, IL-4, IL-10, and interferon- (IFN) y] and numbers of cytokine expressing CD3+ T cells (IL-2, IL-4, IL-10, and IFN-gamma) were quantified by means of enzyme-linked immunosorbent assay and two-color flow cytometry respectively. IFN-gamma gene polymorphisms were determined by polymerase chain reaction and autoradio graphy. RESULTS: Large interindividual variations in both the quantity of IL-2, IL-4, IL-10, and IFN-gamma cytokine protein secreted and numbers of IL-2 and IFN-gamma expressing T cells were demonstrated. However, numbers of IL-4 and IL-10 expressing cells were found to be below detectable limits by flow cytometry. In the case of IFN-gamma, a bi-modal distribution was seen for the quantity of protein secreted. In addition, correlations were observed between IL-2 protein and frequency of IL-2 expressing T cells. However, no relationship was found between IFN-gamma protein levels, numbers of IFN-gamma expressing cells and IFN-gamma gene polymorphisms. CONCLUSIONS: We have demonstrated large differences in both numbers of T helper 1 cytokine expressing cells and the quantity of T helper 1 and T helper 2 cytokine protein secreted between normal individuals. Although the amount of IL-2 protein secreted appeared to be determined by the frequency of IL-2 expressing cells, this was not the case for IFN-gamma.     

TNF-alpha, IL-6, IFN-gamma, and IL-10 gene expression polymorphisms and the IL-4 receptor alpha-chain variant Q576R: effects on renal allograft outcome.

BACKGROUND: There has been much interest recently in the effects of various cytokine gene expression polymorphisms on graft outcome. However, the results of these investigations reveal the outcomes to be organ-specific and center-specific. We sought to confirm and add to some of the earlier findings by studying the impact of tumor necrosis factor-alpha (TNF-alpha), interleukin-10 (IL-10), interferon-gamma (IFN-gamma), and interleukin-6 (IL-6) polymorphisms and the interleukin-4 (IL-4) receptor alpha-chain variant on posttransplant renal allograft outcome. METHOD: TNF-alpha, IL-6, IFN-gamma, and IL-10 gene promoter region polymorphisms were assayed genotypically by PCR-SSP on 120 patients transplanted at the Albany Medical Center. These patients were also typed for the IL-4 receptor alpha-chain variant Q576R. RESULTS: Producers of high levels of the proinflammatory cytokine TNF-alpha were found to be at increased risk for acute rejection episodes if the allograft was mismatched for the molecular products of the class II region of the human major histocompatibility complex (HLA-DR). Expression level polymorphisms of the IL-6, IFN-gamma, and IL-10 genes were not associated with acute rejection episodes, nor was the IL-4 receptor alpha-chain variant Q576R. CONCLUSIONS: These data would suggest that the production of high levels of the cytokine TNF-alpha is especially detrimental to graft survival when the recipient's T-helper lymphocytes are being activated by mismatched donor HLA-class II antigens. Typing all potential kidney recipients for TNF-alpha, and providing well-matched organs for high producers of this cytokines, may be expected to increase rejection-free graft survival in these patients.     

Influence of cytokine genes polymorphisms on long-term outcome in renal transplantation

BACKGROUND: Recently, polymorphisms of cytokine genes have been associated with modified gene expression and increased cytokine production. We evaluated the influence of interleukin-10 (IL-10) gene G-1082A, tumour necrosis factor alpha (TNFalpha) gene G-308A and IL-6 gene G-174C polymorphisms on the rejection rate, renal function and long-term outcome in renal transplantation. PATIENTS AND METHODS: We studied n = 224 consecutive patients, who underwent renal transplantation at our centre from 1998 to 2001 (cadaveric: n = 175, living related: n = 49) followed up for 4.9 +/- 2.0 yr and n = 100 healthy volunteers. IL-10 gene G-1082A, TNFalpha gene G-308A and IL-6 gene G-174C polymorphisms were determined by polymerase chain reaction (PCR) amplification. RESULTS: The genotype distribution of the investigated polymorphisms was similar in patients and controls (ns). The age of donor and the recipient, the number of HLA mismatches and cold and warm ischemic time did not differ among patients with different genotypes (ns). No association between cytokine polymorphisms and the incidence of acute rejection episodes was detected (ns). The cytokine genotypes did not correlate with serum creatinine or creatinine clearance at any time during follow up (ns). Furthermore, there was no significant difference in the genotype frequencies among patients experiencing graft failure (ns). Patients with different cytokine gene polymorphisms showed similar outcomes in the Kaplan-Meier analysis of graft survival (ns). Finally, cytokine polymorphisms had no influence on the acute rejection rate or graft outcome also in the subgroup of HLA-DR mismatched grafts (ns). CONCLUSION: Our results suggest that IL-10 gene G-1082A, TNFalpha gene G-308A and IL-6 gene G-174C polymorphisms are no major risk factors in renal transplantation.     

供者细胞因子基因多态性对肾移植受者急性排斥反应发生的影响

目的 研究供者的细胞因子和细胞因子受体基因多态性对肾移植受者急性排斥反应发生的影响.方法 (1)将126例肾移植受者分成急性排斥组和无排斥组,比较可能影响发生急性排斥反应的因素在两组中的分布情况;比较两组受者中供者的13种细胞因子及受体22个位点的基因型及部分细胞因子表达型的分布情况.(2)根据HLA-DR配型分成0～1个HLA-DR位点错配、HLA-DR完全错配两种情况,分别比较阳性基因多态性在急性排斥组和无排斥组中的分布情况.结果 (1)急性排斥组的HLA-DR错配数明显高于无排斥组;无排斥组供者的白细胞介素(IL)-1α889 C/C、IL-1Ra raspI 11100 T/T、IL-4Rd+1902 A/A、转化生长因子(TGF)-β1密码子10 C/C、IL-10-1082A/A、IL-10低表达型的频率明显较高,IL-12～1 188 A/A、IL-2-330 G/G、IL-10 GCC/ATA频率明显较低;(2)HLA-DR 0～1个位点错配时,两组供者中IL-1Rα msp I 11100 T/T、IL-4Rα+1902 A/A、TGF-β1密码子10 C/C、IL-2-330 G/G、IL-10低表达型频率明显不同,而在HLA-DR完全错配时,只有IL-12-1188 A/A表达频率明显不同.结论 供者的IL-1α-889 C/C、IL-1Rα msp I 11100 T/T、IL-4Rα+1902 A/A、TGF-β1,密码子10 C/C、IL-10-1082 A/A和IL-10低表达型是不发生肾移植急性排斥反应的遗传学指标,而IL-12-1188 A/A、IL-2-330 G/G则是发生急性排斥反应的遗传学危险因素.HLA-DR错配状况可干扰供者细胞因子基因多态性对急性排斥反应发生的影响.     

Influence of patient and donor cytokine genotypes on renal allograft rejection: evidence from a single centre study

Cytokines are key immune mediators and it has been suggested that cytokine gene polymorphisms affecting expression influence rejection or tolerance. This study sought to examine this hypothesis with the aim of identifying predictive genotype markers for rejection. The study group consisted of 120 consecutive first cadaveric recipient-donor pairs transplanted at a single centre, between 1994 and 1997. PCR utilising sequence-specific primers (SSP) methodology was optimised for genotyping recipient and donor DNA for the following polymorphisms: tumour necrosis factor (TNF) -alpha (-308, G/A), interleukin (IL)-10 (-1082, G/A), IL-4 (-590, C/T), transforming growth factor (TGF) -beta1 (+915, G/C). Recipient-donor pairs were divided into rejectors (n = 28) and non-rejectors (n = 92). Each group was further stratified according to number of rejection episodes and HLA-DR mismatching. Recipient-donor pairs both lacking the IL-4*T allele (recipient low producer/donor low producer) were significantly increased in the rejector group (P = 0.02). Also, the combination of recipient IL-10*A negative/donor IL-10*A positive (recipient high producer/donor low producer), was significantly decreased in multiple rejectors (P = 0.04). No significant associations were detected between TNF-alpha and TGF-beta1, and rejection. This study suggests that the combination of recipient-donor IL-4 and IL-10 genotypes may be important in renal transplantation outcome. The results appear to corroborate the protective role of both of these cytokines, possibly due to their ability to suppress inflammation. However, due to conflicting results from this and other studies, a multi-centre collaborative study may be required to determine whether cytokine genotypes are significant, independent predictors of renal allograft rejection.     

Donor genomics influence graft events: the effect of donor polymorphisms on acute rejection and chronic allograft nephropathy

BACKGROUND: Organs procured from deceased donors emanate from individuals with diverse genetic backgrounds. Donor organs, therefore, may vary in their response to injury and immune stimuli in a genetically determined manner. We assessed polymorphisms from 244 renal allograft donors to better understand the impact of donor polymorphisms on selected transplant outcomes. METHODS: Donor genomic DNA restriction fragment length polymorphisms were assayed for evidence of common cytokine [interleukin (IL)-2, IL-6, IL-10, tumor necrosis factor (TNF)-alpha, TGF-beta, interferon (IFN)-gamma] and chemokine (CCR2, CCR5) polymorphisms. Associations between donor polymorphisms and graft events were determined using chi-square, linear regression, and Kaplan-Meier analyses. RESULTS: Several genotypic polymorphisms demonstrated a modest association with acute rejection, including the transforming growth factor (TGF)-beta T/C codon 10 (P= 0.027) and the CCR5 G/A 59029 (P= 0.039) genes by chi-square analysis. Notably, the presence of the T allele in the IFN-gamma gene (+874) demonstrated a highly significant association with biopsy-proven chronic allograft nephropathy (P < 0.008). This association remained highly significant in a multiple linear regression model that incorporated biopsy-proven acute rejection as a covariate. CONCLUSION: These data suggest that many of the donor polymorphisms studied in this analysis may influence a recipient's immune response to a renal allograft. However, their greatest impact may be demonstrated in long-term outcomes.     

Cytokine gene polymorphism and early graft rejection in liver transplant recipients

Cytokines, which play important roles in allograft rejection, show variable production among individuals. These variations may be related to genetic polymorphisms within the regulatory regions of the cytokine genes. We investigated the association between the role tumor necrosis factor alpha (TNF-alpha), transforming growth factor-beta (TGF-beta), interferon gamma (IFN-gamma), interleukin (IL)-10 and IL-6 gene polymorphisms and early graft rejection among liver transplant recipients. Forty-three liver transplant recipients enrolled in this study were divided into 2 groups based on events in the first 2 months posttransplantations, namely, those experiencing at least 1 rejection episode (n = 26) or those without any episode (n = 17). The allele or genotype frequencies of cytokine gene polymorphisms showed no difference between liver recipients with or without nonrejection. In conclusion, there was no significant correlation between early graft rejection and cytokine gene polymorphism of TNF-alpha, TGF-beta, IL-10, IL-6, and IFN-gamma in liver transplant recipients.     

Immune response gene polymorphisms in renal transplant recipients

BACKGROUND: T-cell activation and regulation are under genetic control and vary between individuals. However, the influence of functional immune response gene polymorphisms on transplant outcomes remains controversial. METHODS: A case-control design compared 100 white renal transplant recipients with or without acute graft rejection during the first year posttransplant and 50 normal controls. The polymorphic frequencies of the T-cell signaling genes CD45, CD40L and CTLA-4, and the cytokine genes TNF-alpha, IFN-gamma, IL-10 and TGF-beta1 were studied. The primary analysis examined rejection risk, and subsidiary analyses graft failure and patient death. RESULTS: Multivariate analysis showed no significant association between acute rejection and single nucleotide polymorphisms in CTLA-4, TGF-beta1, IL-10 or TNF-alpha genes or dinucleotide repeat polymorphisms in IFN-gamma and CD40L genes. Allele CD40L-147 was associated with reduced graft failure (P=0.004), and TGFb-25pro with increased graft failure (P=0.0007), although the latter showed a bidirectional dose effect. There was no significant association between patient death and any polymorphisms in the genes examined. The variant (G) allele of the CD45 gene was not detected in the study population. Minor differences in carriage rates observed by univariate analysis did not predict graft or patient outcome in multivariate analysis. CONCLUSION: The primary analysis demonstrated no significant association between the immune response gene polymorphisms examined and acute renal graft rejection in Caucasian patients receiving triple immunosuppression. Subsidiary analyses suggesting an influence of CD40L and TGFbeta1 genes on graft survival require independent confirmation.     

Cytokine gene polymorphism in kidney transplantation--impact of TGF-beta 1, TNF-alpha and IL-6 on graft outcome

Chronic allograft nephropathy (CAN) is one of the main causes of graft loss in renal transplantation. Polymorphisms with functional significance in the promoter and coding regions of cytokine genes have been suggested as a possible factor for graft rejection. The aim of this study was to investigate the impact of cytokine gene polymorphism of pro and anti-inflammatory cytokines on development of CAN in a group of renal transplant patients and donors. Eight single nucleotide polymorphisms (SNPs) including TNFA (-308), TGFB1 (cdns10, 25), IL-10 (-1082, -819, -592), IL-6 (-174) and IFNG (+874) were analyzed in 56 patients with stable graft function (SGF), 10 with CAN and 28 kidney donors by PCR-SSP method. CAN was significantly associated with the recipient TGFB1 cod10 T/T and combination of cods10, 25 T/T G/G genotypes (high producer), (p<0.05). Influence of patient's TNFA genotype correlated with high level of gene expression on the development of CAN was further demonstrated when the patients were stratified according to the HLA mismatches (HLA-DRB MMs). Additionally donor TNFA-308 G/A (high) and IL-6-174 CC (low) genotypes were increased in cases with CAN. No statistically significant differences in distribution of IL-10, IL-6 and IFNG genotypes between recipients with SGF and CAN were found. In conclusion our data suggest that the high producer genotype of profibrogenetic TGF-beta1, pro-inflammatory TNF-alpha and genetically determined low production of immunoregulatory IL-6 cytokine might be risk factors for CAN development.     

Molecular genetic analysis of interleukin-1 promoter and receptor antagonist tandem repeat polymorphisms among HLA-identical renal transplant recipient and donor pairs

The cytokine gene polymorphisms as well as the minor histocompatibility antigen (mHAg) disparities have been thought to result in transplant graft rejection and graft-versus-host reaction between HLA-identical donor/recipient pairs. We detected interleukin (IL)-1 promoter and receptor antagonist tandem repeat polymorphisms among 21 HLA identical renal transplant recipient and donor pairs; of 21 pairs, 15 (71%) showed at least one locus difference between donor and recipient, and 73% of the pairs with the disparities at these loci showed either recipient to donor (R-->D) or donor to recipient (D-->R) positive CD4+ cell response measured by a modified Cylex assay developed in our laboratory. Allele 2 of IL-1 receptor antagonist genotype (IL-1ra VNTR), a gene associated with an increasing IL-1beta production, was detected in the three recipients who developed rejections. One HLA-identical pair that had variations on all four loci of IL-1 gene cluster consistently showed positive CD4+ cell immune responses between the donor and the recipient. This study may provide information of the role of non-HLA genes participating in allograft rejection; this demonstrates that in addition to the disparities of the mHAgs, the non-HLA antigens have to be considered as risk factors in HLA-identical solid organ transplantation.     

Ethnicity Greatly Influences Cytokine Gene Polymorphism Distribution

Polymorphisms in the regulatory regions of cytokine genes are associated with high and low cytokine production and may modulate the magnitude of alloimmune responses following transplantation. Ethnicity influences allograft half-life and the incidence of acute and chronic rejection. We have questioned whether ethnic-based differences in renal allograft survival could be due in part to inheritance of cytokine polymorphisms. To address that question, we studied the inheritance patterns for polymorphisms in several cytokine genes (IL-2, IL-6, IL-10, TNF-alpha, TGF-beta, and IFN-gamma) within an ethnically diverse study population comprised of 216 Whites, 58 Blacks, 25 Hispanics, and 31 Asians. Polymorphisms were determined by allele-specific polymerase chain reaction and restriction fragment length analysis. We found striking differences in the distribution of cytokine polymorphisms among ethnic populations. Specifically, significant differences existed between Blacks and both Whites and Asians in the distribution of the polymorphic alleles for IL-2. Blacks, Hispanics and Asians demonstrated marked differences in the inheritance of IL-6 alleles and IL-10 genotypes that result in high expression when compared with Whites. Those of Asian descent exhibited an increase in IFN-gamma genotypes that result in low expression as compared to Whites. In contrast, we did not find significant ethnic-based differences in the inheritance of polymorphic alleles for TNF-alpha. Our results show that the inheritance of certain cytokine gene polymorphisms is strongly associated with ethnicity. These differences may contribute to the apparent influence of ethnicity on allograft outcome.     

Association of cytokine polymorphic inheritance and in vitro cytokine production in anti-CD3/CD28-stimulated peripheral blood lymphocytes.

BACKGROUND: Genetic variations in cytokine genes are thought to regulate cytokine protein production. However, studies using T cell mitogens have not always demonstrated a significant relationship between cytokine polymorphisms and in vitro protein production. Furthermore, the functional consequence of a polymorphism at position -330 in the IL-2 gene has not been described. We associated in vitro protein production with cytokine gene polymorphic genotypes after costimulation of cultured peripheral blood lymphocytes. METHODS: PBL were isolated from forty healthy volunteers. Cytokine protein production was assessed by enzyme-linked immunosorbent assay. Polymorphisms in interleukin- (IL) 2, IL-6, IL-10, tumor necrosis factor (TNF-alpha), tumor growth factor (TGF-beta), and interferon (IFN-gamma) were determined by polymerase chain reaction (PCR). RESULTS: Statistical difference between protein production and cytokine polymorphic variants in the IL-10, IFN-gamma, and TNF-alpha genes was not evident after 48-hour stimulation with concanavalin-A. In contrast, after anti-CD3/CD28 stimulation significant differences (P<0.05) were found among high and low producers for IL-2, IL-6, and among high, intermediate, and low producers for IFN-gamma, and IL-10. Augmented levels of IL-2 in individuals that were homozygous for the polymorphic IL-2 allele were due to an early and sustained enhancement of IL-2 production. No association was found among TNF-alpha and TGF-beta genotypes and protein production. CONCLUSION: Polymorphisms in IL-2, IL-6, IL-10, and IFN-gamma genes are associated with their protein production after anti-CD3/CD28 stimulation. The profound effect of the IL-2 gene polymorphism in homozygous individuals may serve as a marker for those that could mount the most vigorous allo- or autoimmune responses, or perhaps become tolerant more easily.     

Cytokine polymorphisms do not influence acute rejection in renal transplantation under tacrolimus-based immunosuppression

INTRODUCTION: Acute rejection remains an important cause of graft loss after renal transplantation. It has been suggested that cytokine genotyping may play a predictive role in identifying individuals who are at higher risk of acute rejection with a view to individualizing their immunosuppression. The aim of this study was to investigate any possible associations between acute rejection and certain cytokine polymorphisms. METHODS: We genotyped 91 cadaveric renal transplant recipients on tacrolimus-based immunosuppression and 84 of their donors. The cytokine polymorphisms studied were the following: tumor necrosis factor (TNF)-alpha-1032 T/C, TNF-alpha-865 C/A, TNF-alpha-859 G/A, interleukin (IL)1-R1-970 C/T, IL-10 haplotype [-1082, -819, -592], and IL-6-174 C/G. RESULTS: We found no association between any polymorphism and the incidence of acute rejection. This was true for both the recipient and donor population. CONCLUSION: Cytokine polymorphisms did not influence acute rejection in our study. We conclude that in the modern era of immunosuppression cytokine genotyping is not a significant predictor of acute rejection in renal transplantation.     

Donor cytokine genotype influences the development of acute rejection after renal transplantation

BACKGROUND: Acute allograft rejection remains an important cause of morbidity after kidney transplantation, and has been shown to be a crucial determinant of long-term graft function. Although rejection is mediated by recipient lymphocytes, both donor and recipient factors contribute to the local environment that influences the nature, severity, and duration of the rejection response. Cytokines are a major determinant of this milieu, and this study sought to explore the impact of donor cytokine and cytokine receptor gene polymorphisms on acute rejection after renal transplantation. METHODS: A total of 145 cadaveric renal allograft donors were selected for analysis according to the presence or absence of graft rejection in the first 30 days after transplantation. DNA was genotyped for 20 polymorphisms in 11 cytokine and cytokine receptor genes using the polymerase chain reaction with sequence specific primers. Associations were assessed using contingency table analysis and the chi2 test, using a two-set design. RESULTS: A polymorphism at position -174 of the donor IL-6 gene was associated with the incidence (P=0.0002) and severity (P=0.000007) of recipient acute rejection. This finding was independent of HLA-DR matching. Acute rejection was not influenced by recipient IL-6 genotype, or by donor-recipient matching of IL-6 genotype. CONCLUSION: This study identifies donor IL-6 genotype as a major genetic risk factor for the development of acute rejection after renal transplantation. This provides evidence that donor-derived cytokines play a major role in determining outcome after transplantation, and will contribute to the development of therapeutic algorithms to predict individuals at particularly high risk of acute rejection.     

Increased IFN-gamma response to transplantation antigens measured by cytokine MLC: indications for a bi-phasic response pattern

The immunological reactivity to major histocompatibility transplantation antigens (MHC) is important in clinical manifestations such as graft rejection and graft-vs.-host disease. To evaluate the allogeneic cytokine response pattern we used a newly developed cytokine mixed leukocyte culture (MLC) technique. Blood mononuclear cells from healthy women (n=6) were exposed to cells from another person and to pooled cells from 28 blood donors (MHC-pool). The secretion kinetics of IL-4 and IFN-gamma from the responder cells was analysed by ELISPOT. We found a higher IFN-gamma response to the MHC-pool compared with the IL-4 secretion. Both the total secretion of IFN-gamma for 7 days and the median value of IFN-gamma in each individual was increased compared with IL-4. The IFN-gamma response showed a bi-phasic pattern with the major peak on day 6-7. Our results indicate that allo-responses are mainly Th1-like responses, displaying a bi-phasic pattern. This knowledge may be useful, and the methods suitable, in the studies of allo-responses in transplantation and pregnancy.     

Cytokine gene polymorphisms predict acute graft rejection following renal transplantation.

BACKGROUND: The proinflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) has been implicated in the pathogenesis of acute rejection, while animal models suggest a role for interleukin-10 (IL-10) in promoting graft survival. It has also been shown that polymorphisms in the TNFA gene promoter (position -308) and in the IL-10 gene promoter (position -1082) correlate with differential production of these cytokines in vitro. The aim of this study was to determine whether TNF-alpha and IL-10 gene polymorphisms influence the incidence and severity of acute rejection in the first six months following renal transplantation. METHODS: The cytokine genotypes of 115 consecutive first cadaveric kidney allograft recipients and their donors were screened. The rejection episodes (REs) were defined clinically and confirmed histologically where possible and further classified according to severity (RS), namely steroid-resistant or responsive REs. The genotypes were then correlated with the REs and RS. RESULTS: The recipient TNF-alpha high producer genotype and IL-10 high producer genotype were significantly associated with multiple REs (>/=2) in human leukocyte antigen (HLA)-DR mismatched transplants (P = 0.0047 and P = 0.045, respectively), whereas only the TNF-alpha high producer genotype was associated with steroid-resistant REs (P = 0.025). When recipient cytokines were analyzed together, the TNF-alpha high/IL-10 high producer genotype had the worst prognosis, whereas TNF-alpha low/IL-10 low producer genotype was protective. CONCLUSIONS: We conclude that recipient TNF-alpha and IL-10 gene polymorphisms are determinants of REs and RS following kidney transplantation. Routine screening of these gene polymorphisms may have a clinical role in identifying patients at risk of multiple REs and severe rejections.     

The effect of cytokine gene polymorphisms on pediatric heart allograft outcome.

BACKGROUND: Cytokines play a major role in the inflammatory and immune responses that mediate allograft outcome. Several studies have shown that the production of cytokines varies among individuals and these variations are determined by genetic polymorphisms, most commonly within the regulatory region of the cytokine gene. The aim of this study was to assess the effect of these allelic variations on acute rejection after pediatric heart transplantation. METHODS: We performed cytokine genotyping using polymerase chain reaction-sequence specific primers in 93 pediatric heart transplant recipients and 29 heart donors for the following functional polymorphisms: tumor necrosis factor-alpha (TNF-alpha) (-308), interleukin (IL)-10 (-1082, -819, and -592), TGF-beta1 (codon 10 and 25), IL-6 (-174), and interferon-gamma (INF-gamma) (+874). The distribution of polymorphisms in this population did not differ from published controls. The patients were classified as either non-rejecters (0 or 1 episode) or rejecters (> 1 episode) based on the number of biopsy proven rejection episodes in the first year after transplantation. RESULTS: Forty-two of the 69 TNF-alpha patients (61%) in the low producer group were non-rejecters, while 9 of the 24 (37.5%) with high TNF-alpha were non-rejecters (p = 0.047). In contrast, IL-10 genotype showed the opposite finding. Forty-two of the 66 patients (64%) in the high and intermediate IL-10 group were non-rejecters, while 9 of the 26 (35%) in the low IL-10 group were non-rejecters (p = 0.011). The combination of low TNF-alpha with a high or intermediate IL-10 genotype was associated with the lowest risk of rejection (34/49 or 69% non-rejecters). Neither the distribution of the IL-6, INF-gamma, and TGF-beta1 genotype in recipients nor the donor genotype showed any association with acute rejection. CONCLUSION: Genetic polymorphisms that have been associated with low TNF-alpha and high IL-10 production are associated with a lower number of acute rejection episodes after pediatric heart transplantation.     

Expression of HLA antigens on renal tubular cells in culture. II. Effect of increased HLA antigen expression on tubular cell stimulation of lymphocyte activation and on their vulnerability to cell-mediated lysis

Episodes of renal allograft rejection are characterized by an infiltrate of mononuclear leukocytes into the graft and increased HLA antigen expression by graft tubular cells. As HLA antigens are important immune-recognition molecules, we examined whether their increased expression during rejection might contribute to the rejection process. Interferon gamma (IFN-gamma)-treatment of cultured human kidney (HK) cells induced them to increase HLA antigen expression and caused a slight, but nonsignificant increase in their capacity to stimulate proliferation of allogeneic lymphocytes in primary mixed lymphocyte kidney culture (MLKC) (maximum of 8110 +/- 5015 vs. 3966 +/- 4050 counts/min on day 8), which was further increased by addition of IL-1. This proliferation never approached that induced by peripheral blood mononuclear stimulator cells (maximum of 40,325 +/- 10,694 counts/min on day 5), and addition of HK cells to mixed lymphocyte culture inhibited proliferation. There was no difference in lysis of IFN-gamma-treated or untreated HK-cell targets by "specific" cytotoxic effector cells produced in mixed lymphocyte culture using stimulator lymphocytes from the kidney cell donor (49.4 +/- 20% vs. 50.4 +/- 26% specific release in CML). Lysis by 3rd-party cytotoxic effectors produced in MLC using stimulator lymphocytes unrelated to the kidney-cell donor was greater for untreated HK cells (27.4 +/- 20%) than for IFN-gamma-treated HK targets (7.6 +/- 6%, P less than 0.001). IFN-gamma-activated naive mononuclear leukocytes lysed untreated HK targets but not IFN-gamma-pretreated targets, and this nonspecific cytotoxicity was mediated by lymphocyte- but not monocyte-enriched cell populations. HK cells are therefore poor stimulators of alloproliferation even when they express increased HLA antigen. They are lysed by both specific and nonspecific effector cells, and exposure to IFN-gamma makes them less vulnerable to nonspecific cytotoxicity and by inference, more vulnerable to specific cytotoxicity.     

Cytokines and chronic rejection: a study in kidney transplant long-term survivors

BACKGROUND: In part, the long-term survival of kidney transplants depends on the efforts to perform grafts with good human leukocyte antigen (HLA) compatibility, but there are other mechanisms that must induce some sort of tolerance and impair the anti-graft immune reaction. Because cytokines are one of the main components of immune response, we evaluated single nucleotide polymorphisms (SNPs) of several cytokine genes that may influence the production of a given cytokine and therefore the features of immune reactions. METHODS: A total of 416 first cadaveric kidney transplants were monitored for HLA matching. After 10 years, the graft was still functional in 171 of 416 patients; 102 of 171 patients were also typed for cytokine polymorphisms. RESULTS: The mismatch distributions in patients who underwent transplantation were not statistically different from the entire group of patients who underwent transplantation during the same time period. Moreover, it seems that almost all of the HLA class I incompatible long-term survivors are homozygous for GG at the -1082 interleukin (IL)-10 or CC at the -33IL4. CONCLUSIONS: We observed that a match for class I and class II HLA antigens apparently does not favor the long-term survival of transplanted kidneys. In fact, matched grafts are lost before 10 years in the same proportion as the mismatched grafts. We also demonstrated (1) that patients who are homozygous for GG at the SNP -1082IL10 (high IL-10 producers) and HLA class I mismatched (but matched for class II) are protected from chronic rejection, and (2) that patients who are homozygous for CC at the SNP -33IL4 (low IL-4 producers) and HLA class I mismatched (regardless of matching for class II) are protected from chronic rejection.