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Background: Accumulating data indicate that sub‐therapeutic levels of tacrolimus are associated with long‐term kidney graft loss. However, elevated doses increase the risk of infection and drug toxicity, which also threaten graft and patient longevity. We sought to determine the minimal tacrolimus level required to maintain graft survival. Methods: We conducted a single‐center historical cohort study. The first‐year post‐transplant exposure time was calculated for each of the five tacrolimus trough level intervals. This measure was adjusted to the exposure time below a given interval level, allowing us to define the threshold for the optimal tacrolimus level as the upper limit of the interval. We then determined the association between the adjusted exposure time at each tacrolimus level interval and our primary outcome, death‐censored graft loss. Results: One thousand four hundred and seventeen patients with a median follow‐up of 5.3 years were included in the final cohort. The tacrolimus level interval of 5–6 ng/ml was the highest interval, which demonstrated a statistically significant association between adjusted exposure time and increased risk of graft loss (HR 1.58, per log days, p =.002). Cumulative exposure time above 14 days with a tacrolimus level below 6 ng/ml was associated with an increased rate of graft loss in most studied subgroups, except for recipients with pre transplant diabetes. Conclusions: Maintaining tacrolimus levels above 6 ng/ml during the first‐year post‐transplant might improve kidney graft survival. [ABSTRACT FROM AUTHOR]

Background and purpose: Kidney transplant is a major form of renal replacement therapy in many patients at advanced stages of the disease. Transplant rejection is a major complication following kidney transplant that could be reversible or irreversible. The present study was done to investigate the incidence of irreversible kidney transplant rejection. Materials and methods: A retrospective cohort study was performed using the information on 1571 renal transplants in Kermanshah, Iran, 1989 to 2016. Kaplan-Meier, Cox regression, and log-rank test were used to estimate the incidence of kidney transplant rejection 24 hr after surgery, the graft survival rate, and investigating the differences between the subgroups, respectively. Results: The rate of acute transplant rejection was 3.82% and the rejection rates within 6 months, one and three years after the transplantation were 10.06%, 12.41%, and 18.20%, respectively. The Cox regression model showed significant correlations between age (P=0.013), creatinine level (P=0.001), and diabetes (P=0.016) and survival rate of kidney transplants. Conclusion: High incidence of acute rejection and rejection within six months showed the influence of some underlying factors. Further studies on underlying variables that affect transplant rejection and kidney transplantation at younger ages could be of great benefit in increasing kidney transplantation survival.

Background and purpose: Kidney transplant is a major form of renal replacement therapy in many patients at advanced stages of the disease. Transplant rejection is a major complication following kidney transplant that could be reversible or irreversible. The present study was done to investigate the incidence of irreversible kidney transplant rejection. Materials and methods: A retrospective cohort study was performed using the information on 1571 renal transplants in Kermanshah, Iran, 1989 to 2016. Kaplan-Meier, Cox regression, and log-rank test were used to estimate the incidence of kidney transplant rejection 24 hr after surgery, the graft survival rate, and investigating the differences between the subgroups, respectively. Results: The rate of acute transplant rejection was 3.82% and the rejection rates within 6 months, one and three years after the transplantation were 10.06%, 12.41%, and 18.20%, respectively. The Cox regression model showed significant correlations between age (P=0.013), creatinine level (P=0.001), and diabetes (P=0.016) and survival rate of kidney transplants. Conclusion: High incidence of acute rejection and rejection within six months showed the influence of some underlying factors. Further studies on underlying variables that affect transplant rejection and kidney transplantation at younger ages could be of great benefit in increasing kidney transplantation survival. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Basically chronic graft rejection is a type-IV hypersensitivity process, also known as delayed-type hypersensitivity (DTH). The role of cytokines secreted from T-cell lymphocytes is known in this process. Among these cytokines, the biggest role belongs to the transforming growth factor beta (TGF-β) and interleukin-2 (IL-2). Many studies have been published on the effect of low level lasers (LLL) on DTH, but not many have focused on the mechanism of LLL effects on DTH, which is also the mechanism of chronic graft rejection. If LLL are able to decrease the level of cytokines effectively in this process, then it would be possible to use it to prevent chronic graft rejection, either alone or combined with routine treatments, to give fewer treatment side effects. This study was designed to evaluate the effect of LLL on the amount of cytokines secreted by T-cells after stimulation in vitro by foreign antigens. Method and materials: Human peripheral blood mononuclear cells were cultured and the cells were divided into 4 groups (control #1, control #2, case #1, and case #2). Control group #1 was the base group and the cells received neither stimulation nor irradiation. Control group #2 was only stimulated by phytohaemagglutinin (PHA); no laser irradiation was carried out. Case group #1 received daily laser irradiation for a total of 9 days, starting one day prior to stimulation with PHA. Case group #2 was given daily laser irradiation for a total of 7 days, starting one day after the stimulation with PHA. Both case groups were irradiated with the same helium-neon (HeNe) laser device (parameters: 632.8nm, 4J/cm2). On days 3, 5 and 8 of the experiment, the level of the cytokines interleukins IL-2 and IL-12, TGF-β and interferon gamma (INT-γ) were checked by the ELISA method in all the groups and the data were analyzed using SPSS 11.5. Results: Our results showed that low-level irradiation can decrease the level of cytokines that are known to be stimulators for chronic graft rejection (IL-2, IL-12, TGF-β and INF-γ). However, we did not find any significant differences between our two case groups. Discussion: Although this study suggests the successful role of LLL in preventing chronic graft rejection by affecting the cytokines known to have significant role in this process, further experimental studies and dosage determination experiments are required before using LLL in clinical treatment procedures. [Copyright &y& Elsevier]