Diagnosis of acute renal allograft rejection by analyzing whole blood mRNA expression of lymphocyte marker molecules.

BACKGROUND: Currently, the diagnosis of acute rejection after kidney transplantation is based on a kidney biopsy taken after clinical rejection suspicion. A robust, noninvasive diagnostic method would allow easier and more frequent monitoring of the patient and the graft. Potentially, a straightforward method would be the analysis of lymphocyte marker molecule expression from whole blood samples. METHODS: Whole blood samples were collected prospectively in a single kidney transplantation center from 50 adult kidney recipients transplanted between 2001 and 2005. The mRNA expression of granzyme B, perforin, FasL, granulysin, CD154, ICOS, CTLA4 and PD-1 were analyzed with real-time quantitative polymerase chain reaction. RESULTS: The expression of ICOS and CD154 were significantly lower in rejection patients than in control patients (P<0.001). Both genes gave statistically significant area under receiver operating characteristic curve (AUC; 0.87, 0.88) with 84% sensitivity and 100% specificity for CD154 and 76% and 86% for ICOS, respectively. In paired rejection and postrejection therapy samples, the expression of both genes significantly increased during rejection therapy (P<0.001). When rejection patients were compared to patients biopsied because of other reasons of graft dysfunction, both CD154 and ICOS were lower in rejection patients but only CD154 was statistically significant (P=0.028, AUC=0.740, sensitivity 52%, specificity 90%). The other studied genes gave no consistent statistically significant results. CONCLUSIONS: The whole blood gene expression quantities of costimulatory molecules CD154 and ICOS reasonably robustly differentiated rejection patients from control patients. The clinical use of the analysis is limited by poor capability to differentiate patients with rejection from patients with other causes of graft dysfunction.

The impact of donor cytokine gene polymorphisms on the incidence of cytomegalovirus infection after kidney transplantation.

Cytomegalovirus (CMV) seronegative recipients of kidneys from CMV seropositive donors are at a high risk of CMV infection after transplantation since viruses in the allograft may reactivate in patients without prior immunity. We hypothesized that the genetic background of the graft has an influence on the incidence of infection. Effects of IL10, IL6 and IFNG gene polymorphisms, known to affect CMV infectivity, were investigated in 71 CMV seronegative recipients of grafts from CMV seropositive cadaver donors. Donor IL10(-1082 AA) genotype reduced the incidence of CMV infection (p=0.031) and CMV episodes in these patients tended to occur later (AA: median 83 days, AG/GG: median 45 days, p=0.072). In multivariate analysis, other explaining factors than the donor IL10(-1082 AA) genotype alone did not improve Cox hazard model (HR=0.3, 95% CI=0.09-0.96, p=0.043). Recipient polymorphisms did not reduce the incidence of CMV infection. We conclude that donor IL10 gene polymorphisms may influence the likelihood of CMV infection in the high risk patients investigated.

Cytokine gene polymorphisms and risks of acute rejection and delayed graft function after kidney transplantation.

BACKGROUND: Pretransplantation identification of patients at an increased risk for adverse events would allow more individualized treatment strategies possibly improving long-term outcome. We studied cytokine gene polymorphisms of kidney allograft recipients and their donors to identify factors predisposing for acute rejection (AR) and delayed graft function (DGF). METHODS: A total of 291 adult cadaver kidney recipients transplanted at a single transplantation centre between 1999 and 2002 were investigated. Recipients and donors were typed for TNF-alpha(-308G/A), TGF-beta1(codon 10T/C, codon 25C/G), IL-10(-1082G/A, -819C/T, -592C/A), IL-6(-174C/G), and IFN-gamma(+874T/A) polymorphisms using a SSP-PCR kit. An AR episode was defined based on clinical and histological findings (Banff criteria). RESULTS.: The incidence of AR was 17%. In univariate statistical analyses recipients with TNF-alpha -308AA-genotype were found to be at a significantly increased risk for rejection (odds ratio [OR] 5.0, 95% CI 3.0-8.3, P = 0.003). The association was independent from the patient-donor HLA-mismatch status. In addition, patients with IL-10 ACCACC, ATAATA, GCCATA (-1082A/G, -819C/T, -592C/A, respectively) haplotypes were predisposed to rejection (OR 1.9, 95% CI 1.1-3.1, P = 0.016). Further, the combination of recipient TGF-beta1 25GG-genotype and donor IL-10 -819T-allele was associated with rejection (OR 1.8, 95% CI 1.1-3.0, P = 0.027). These variables remained significant risk factors also in a multivariate logistic regression analysis. The incidence of DGF was 22%. The risk was increased by a donor TNF-alpha -308GA-genotype (OR 1.6, 95% CI 1.1-2.6, P = 0.040). CONCLUSIONS: Our results confirm that cytokine gene polymorphisms influence the outcome of kidney transplantation. Our data especially identify the TNF-alpha -308AA-genotype as a factor predisposing for AR episodes.

Lack of association between thrombosis-associated and cytokine candidate gene polymorphisms and acute rejection or vascular complications after kidney transplantation.

BACKGROUND: Acute rejection episodes and vascular complications are common after renal transplantation and have negative impact on the long-term patient and graft survival. We investigated whether the risks of acute rejection, thrombosis, infarction and graft loss could be predicted based on the presence of functional polymorphisms in the genes of the coagulation and endothelial inflammation cascade. METHODS: The study consisted of 772 consecutive cadaver kidney transplantations from a single centre. The effects of gene polymorphisms FVL, F5R2, FII G20210A, MTHFR C677T, F13A1 V34L, TFPI P151L, PROC W380G, TNF G(-308)A, IL10 A(-592)C, IL10 A(-1082)G and IL6 C(-174)G of recipients and donors were investigated. RESULTS: We were unable to find statistically significant associations between any of the studied polymorphisms and clinical outcomes. CONCLUSIONS: Our results indicate that high-risk renal transplant candidates cannot be identified through the routine analysis of the polymorphisms.