Mycophenolate mofetil and C-reactive protein in renal transplant recipients

Cardiovascular disease after transplantation: an emerging role of the immune system

Cardiovascular disease (CVD) after transplantation remains a major concern. Little is known about what drives the increased cardiovascular risk in transplant recipients apart from traditional risk factors. The immune system is involved in the pathogenesis of hypertension, atherosclerosis, and coronary artery disease in the general population. Recently, inhibition of interleukin 1 - β by canakinumab versus placebo decreased the incidence of cardiovascular events. Emerging evidence points to a role of adaptive cellular immunity in the development of CVD. Especially, expansion of pro-inflammatory and antiapoptotic cytotoxic CD4⁺ CD28^null T cells is closely associated with incident CVD in various study populations including transplant recipients. The association of cytomegalovirus exposure with increased cardiovascular mortality might be explained by its capacity to upregulate these cytotoxic cells. Also, humoral immunity seems to be relevant for cardiovascular outcome in transplant recipients. Panel-reactive antibodies at baseline and donor-specific antibodies are independently associated with poor cardiovascular outcome after kidney transplantation. Cardiovascular effects of immunosuppressive drugs and statins do not only imply indirect positive or negative effects on traditional cardiovascular risk factors but also intrinsic immunological effects. How immunosuppressive drugs modify atherosclerosis largely remains elusive.

Cardiovascular risk factors following renal transplant

Kidney transplantation is the gold-standard treatment for many patients with end-stage renal disease. Renal transplant recipients (RTRs) remain at an increased risk of fatal and non-fatal cardiovascular (CV) events compared to the general population, although rates are lower than those patients on maintenance haemodialysis. Death with a functioning graft is most commonly due to cardiovascular disease (CVD) and therefore this remains an important therapeutic target to prevent graft failure. Conventional CV risk factors such as diabetes, hypertension and renal dysfunction remain a major influence on CVD in RTRs. However it is now recognised that the morbidity and mortality from CVD are not entirely accounted for by these traditional risk-factors. Immunosuppression medications exert a deleterious effect on many of these well-recognised contributors to CVD and are known to exacerbate the probability of developing diabetes, graft dysfunction and hypertension which can all lead on to CVD. Non-traditional CV risk factors such as inflammation and anaemia have been strongly linked to increased CV events in RTRs and should be considered alongside those which are classified as conventional. This review summarises what is known about risk-factors for CVD in RTRs and how, through identification of those which are modifiable, outcomes can be improved. The overall CV risk in RTRs is likely to be multifactorial and a complex interaction between the multiple traditional and non-traditional factors; further studies are required to determine how these may be modified to enhance survival and quality of life in this unique population.

Delta Neutrophil Index as a Marker for Differential Diagnosis between Acute Graft Pyelonephritis and Acute Graft Rejection

Introduction

The delta neutrophil index (DNI) is the fraction of circulating immature granulocytes, which reflect infectious and/or septic condition. Acute graft pyelonephritis (AGPN) versus acute graft rejection is a frequently encountered diagnostic and therapeutic dilemma in kidney transplant recipients, but little is known about the clinical usefulness of DNI value in the differentiation of the two conditions.

Material & Methods

A total of 90 episodes of AGPN or acute graft rejection were evaluated at the Kangdong Sacred Heart Hospital between 2008 and 2014. We performed retrospective analysis of demographic, clinical, and laboratory parameters data. Receiver operating curves (ROC) and multivariate logistic regression were conducted to ascertain the utility of DNI in discriminating between AGPN and acute graft rejection.

Results

AGPN group had significantly higher DNI values than acute graft rejection group (2.9% vs. 1.9%, P < 0.001). The area under the ROC curve for DNI value to discriminate between AGPN and acute graft rejection was 0.85 (95% confidence interval [CI]; 0.76–0.92, P < 0.001). A DNI value of 2.7% was selected as the cut-off value for AGPN, and kidney transplant recipients with a DNI value ≥ 2.7% were found to be at a higher risk of infection than those with a DNI < 2.7% (odd ratio [OR] 40.50; 95% CI 8.68–189.08; P < 0.001). In a multivariate logistic regression analysis, DNI was a significant independent factor for predicting AGPN after adjusting age, sex, log WBC count, log neutorphil count, log lymphocyte count, CRP concentration, and procalcitonin concentration (OR 4.32; 95% CI 1.81–10.34, P < 0.001).

Conclusions

This study showed that DNI was an effective marker to differentiate between AGPN and acute graft rejection. Thus, these finding suggest that DNI may be a useful marker in the management of these patients.

Lower total and percent of high-molecular-weight adiponectin concentration in South Asian kidney transplant recipients

BACKGROUND

Ethnicity is an important determinant of post-renal transplant outcomes. Limited data are available on cardiovascular risk differences in kidney transplant recipients (KTR) based on ethnicity.

METHODS

A group of 129 clinically stable age-matched KTR [43 South Asian (SA), 86 Caucasian]) were assessed for plasma total and high-molecular-weight (HMW) adiponectin, cystatin C, apolipoproteins A1 and B, C-reactive protein, uric acid, urine albumin-to-creatinine ratio, estimated glomerular filtration rate (eGFR) and transplant-specific plus traditional Framingham risk factors. SA and Caucasians were compared by t-tests, Wilcoxon rank-sum or chi-square testing. Accounting for the matched design, multivariable linear regression was performed to determine predictors of adiponectin concentrations.

RESULTS

SA did not differ from Caucasians in background cardiac disease or cardioprotective medication use or risk factors other than smoking (26 versus 56%, P = 0.001). Total adiponectin (9.5 ± 3.5 versus 12.9 ± 6.7 μmg/mL, P < 0.001) and HMW adiponectin (22 ± 9 versus 29 ± 11%, P < 0.001) were significantly lower in SA. Determinants of total adiponectin included SA ethnicity (P = 0.02), cystatin C-eGFR (P < 0.001), high-density lipoprotein (HDL) cholesterol (P < 0.0001) and waist-to-hip ratio (P < 0.001), while those of HMW adiponectin included SA ethnicity (P < 0.001), cystatin C-eGFR (P = 0.03) and HDL cholesterol (P = 0.001). There were no important differences in the other measured biomarkers.

CONCLUSION

Total and HMW adiponectin concentrations are lower in SA KTR and may be promising exploratory biomarkers of post-transplant cardiovascular risk.

Subclinical inflammation in renal transplant recipients: impact of cyclosporine microemulsion versus tacrolimus

BACKGROUND

Renal insufficiency and renal transplant (RT) provoke a microinflammatory state that leads to increased atherosclerosis. It is not fully known whether calcineurin inhibitors (CNIs) play a role in the inflammation observed in these patients or whether any differences exist between CNIs.

OBJECTIVES

The study aimed to establish differences in the inflammatory state of two groups treated with cyclosporine microemulsion (CyA) or tacrolimus (TC).

PATIENTS AND METHODS

This prospective study included 81 RT patients divided into two groups according to the CNI: CyA group, n = 35 versus TC group, n = 46. The markers of inflammation (MIF) were determined preRT and at 3 and 12 months' postRT: C-reactive protein (CRP), serum amyloid protein A (SAA), interleukin-6 (IL-6), soluble interleukin-2 receptor (sIL-2R), tumor necrosis factor-alpha (TNF-alpha), and pregnancy-associated plasma protein A (PAPP-A). Samples were collected in stable patients in the absence of rejection, active infection, or inflammatory processes.

RESULTS

No significant differences existed between the markers of inflammation in the two treatment groups prior to transplantation. At 3 months' posttransplant, patients treated with CyA showed significantly higher levels of IL-6 (P = .05), SAA (P = .03), and sIL-2R (P = .008) compared with patients treated with TC. These differences were maintained for IL-6 (P = .03) and sIL-2R (P = .027) at 12 months' posttransplant. A multivariate analysis at 3 months showed that only age [OR 10.1; CI (95% 2.6-38.4); P = .001], SAA [OR 4.8; IC (95% 1.4-16.5); P = .015], and sIL-2R [OR 4.9; IC (95% 1.5-16.2); P = .009] were independent predictors of the CNI used. At 12 months, age [OR 3.7; IC (95% 0.9-14.2] and sIL-2R [OR 6.04; IC (95% 1.5-23); P = .006] continued to be independent predictors.

CONCLUSIONS

Patients treated with CyA displayed significantly higher levels of inflammatory markers (IL-6, SAA, sIL-2R) at 3 and 12 months' posttransplantation, independent of age, gender, time on dialysis, diabetes mellitus (preRT and de novo postRT), and renal function measured by serum creatinine.