Cytokine genotypes in kidney, heart, and lung recipients: consequences for acute and chronic rejection

Role of genetics in lung transplant complications

There is increasing knowledge that patients can be predisposed to a certain disease by genetic variations in their DNA. Extensive genetic variation has been described in molecules involved in short- and long-term complications after lung transplantation (LTx), such as primary graft dysfunction (PGD), acute rejection, respiratory infection, chronic lung allograft dysfunction (CLAD), and mortality. Several of these studies could not be confirmed or were not reproduced in other cohorts. However, large multicenter prospective studies need to be performed to define the real clinical consequence and significance of genotyping the donor and receptor of a LTx. The current review presents an overview of genetic polymorphisms (SNP) investigating an association with different complications after LTx. Finally, the major drawbacks, clinical relevance, and future perspectives will be discussed.

Lung Transplantation: Current Status and Challenges

The lung is an anatomically complex vital organ whose normal physiology depends on actively regulated ventilation and perfusion, and maintenance of a delicate blood-air barrier over a huge surface area in direct contact with a potentially hostile environment. Despite significant progress over the past 25 years, both short- and long-term outcomes remain significantly inferior for lung recipients relative to other "solid" organs. This review summarizes the current status of lung transplantation so as to frame the principle challenges currently facing end-stage lung-failure patients and the practitioners who care for them.

Combined analysis of cytokine genotype polymorphism and the level of expression with allograft function in African-American renal transplant patients

Cytokine gene polymorphism and expression levels were evaluated in a group of African-American patients who had undergone renal transplantation. It was hypothesized that possession of specific cytokine alleles might be influential in predisposing the recipient to allograft rejection. Thus, we sought to establish a relationship between cytokine gene polymorphism, the levels of cytokine expression, and the outcome of allograft function. Cytokine genotypes and mRNA transcript levels of IL-2, TNF-alpha, TGF-beta1, IL-10, IL-6 and IFN-gamma were determined using peripheral blood cells. Genomic DNA samples from 77 transplant recipients and 77 controls were tested by a multiplex PCR with specific primers for the above cytokines. The frequency distributions of cytokines were analyzed in respect to the clinical characterization, including delayed graft function (DGF), rejection episodes (REs) and stable graft function (SGF). The mRNA transcript level was tested both at pre- and early post-transplantation (day 1 and day 4) with primers for coding regions of the above cytokines in a RT-PCR assay. The majority of recipients with successful graft function were matched with their donors for only three out of the six HLA alleles. We have shown that the TGF-beta1 T/C G/G high producer and IFN-gamma T/A intermediate producer genotypes were associated with allograft rejection, whereas low IFN-gamma producer and high IL-10 producer genotypes were significantly protective of the allograft. There was some correlation between the TGF-beta1 high producer genotype and DGF, but it was not statistically significant. Overall, 77% of those who experienced REs carried the TGF-beta1 T/C G/G, high producer genotype as compared with 52% who experienced DGF, 39% with SGF (P<0.01, RR=2.0), and 27.3% of controls (P<0.003, RR=2.6). The IFN-gamma T/A intermediate producer genotype was found in 69.2% of patients with REs as compared with 26.8% of patients with SGF (P<0.008, RR=2.85). The IL-10, ATA/ATA low producer genotype was found in 38.5% of recipients with REs and 14.6% of recipients without REs (P<0.04, RR=0.53). Expression levels of mRNA transcript were correlated with genotype data, except for the TGF-beta1 high producer genotype where there was no significant difference between the level of mRNA transcript at pre- and post-transplantation. Low DRbeta1 and high DPbeta1 expression by recipient peripheral blood mononuclear cells before transplantation was associated with more SGF, whereas high DRbeta1 and low DPbeta1 expression at pretransplantation was associated with more REs (DRbeta1, P<0.001 and DPbeta1, P<0.05, respectively). We concluded that, dual analysis of cytokine genotype and expression levels by peripheral cells may be an important clue to understanding the contribution of the recipient's immune response to an allograft pre- and post-transplantation. Identification of peripheral markers diagnostic of rejection could allow advance anticipation of clinical outcome, and might reduce the need for tissue biopsy.