PCSK9 and inflammatory biomarkers in the early post kidney transplantation period.

OBJECTIVE:   Various biomarkers have been studied in the early post-kidney transplantation (post-KTx) period in order to identify potential therapeutic targets for improving long-term graft survival. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a biomarker that has recently gained interest in cardiovascular disease but its role still remains to be defined post-KTx. PATIENTS AND METHODS: We prospectively evaluated the levels of PCSK9, interleukin (IL)-6, WBC and C-reactive protein in seventy-three hemodialysis patients undergoing KTx, at 3 time-points; pre-transplantation (day 0) and at 1 and 6-months post-KTx. All data were also analyzed according to donor-type (living or deceased) and compared with hemodialysis patients on transplant waiting list. RESULTS: At Day 0 there was no difference in WBC, CRP, IL-6 and PCSK9 levels between patients scheduled for transplantation and those who remained on hemodialysis. In transplanted patients WBC, CRP and IL-6 levels were significantly reduced early post-KTx [logIL-6 Day 0: 0.68 (0.33, 0.85) vs. 1-month: 0.57 (0.37, 0.75) vs. 6-months: 0.50 (0.32, 0.69) pg/ml, p=0.01], while PCSK9 levels were significantly increased (Day 0: 199.8±63.0 vs. 1-month: 276.2±79.4 vs. 6-months: 245.9±62.5 ng/ml, p<0.001). In contrast, no change of WBC, CRP, IL-6 and PCSK9 levels was observed in hemodialysis patients on follow-up (p=NS for all). Between living-donor and deceased-donor recipients, analysis showed reduced CRP and increased PCSK9 levels in both groups (p<0.05 for all), while IL-6 levels were reduced in living-donor and increased in deceased-donor recipients 1-month post-KTx. PCSK9 levels were not correlated with renal function, delayed graft function, rejection episodes or inflammatory biomarkers. CONCLUSIONS: PCSK9 levels were increased post-KTx independently from renal function and inflammatory biomarkers, in both living and deceased-donor recipients.

Syndrome of Inappropriate Antidiuretic Hormone Secretion Complicating Systemic Nocardiosis in a Renal Transplant Recipient: A Case Report.

BACKGROUND: Infection by Nocardia species is an uncommon cause of severe clinical syndromes, particularly in immunocompromised patients, and solid-organ transplantation is the most common underlying condition. The syndrome of inappropriate antidiuretic hormone secretion (SIADH) has been described thus far in lung and stem cell transplants with systemic nocardiosis. CASE REPORT: We report the first case of SIADH in a female elderly renal transplant recipient diagnosed with systemic nocardiosis 2 years after transplantation. The SIADH was managed appropriately, and her immunosuppressive regimen remained unchanged but was adjusted at a lower level. The systemic Nocardia infection was successfully treated with intravenous administration of trimethoprim-sulfamethoxazole and imipenem for 2 weeks followed by oral trimethoprim-sulfamethoxazole for a total of 12 months. CONCLUSIONS: The SIADH syndrome is a recognizable complication of Nocardia infection in renal transplant recipients. Prompt identification along with proper management and prolonged antimicrobial treatment are essential to improve patients' outcome.

Glomerular Diseases and Renal Transplantation: Pathogenic Pathways and Evolution of Therapeutic Interventions.

Glomerular diseases and renal transplantation are the main fields of nephrology in which the immune system plays a prevalent role. Glomerular diseases have traditionally been attributed to auto-immune conditions, whereas allograft rejection has been considered an allo-immune response. However, common immunopathologic mechanisms that include Toll-like receptors, complement and B-cell activation, as well as genetic and infectious factors appear to be involved in the pathogenesis of both entities. Novel therapeutic regimens directed against specific targets of the immune system show promising results in glomerulopathies as well as in renal transplantation.

Patients After Kidney Allograft Failure: Immunologic and Nonimmunologic Considerations.

Patients returning to dialysis after kidney transplant failure represent approximately 5%-15% of the population starting hemodialysis. These patients exhibit a high risk of morbidity and mortality attributed mainly to the exposure to immunosuppressive medications and to a uremic environment. The purpose of this paper was to review data regarding survival after renal allograft failure and the optimal management of patients before returning to dialysis. Moreover, issues surrounding nephrectomy after renal allograft failure, the tapering of immunosuppression and the possibility of retransplantation are examined, because they seem to be crucial for patient survival and the quality of life.

Evolution of Renal Function in Renal Allograft Recipients Under Various Everolimus-Based Immunosuppressive Regimens.

BACKGROUND: Long-term allograft survival is a major challenge in kidney transplantation. This study sought to estimate the evolution of renal function in patients receiving different immunosuppressive regimens based on everolimus (EVR). METHODS: Ninety-nine renal allograft recipients were included in a 12-month open-label, noninterventional, prospective, single-center study. Patients were divided into 2 groups, de novo and late conversion to EVR. RESULTS: Group A included 40 patients under calcineurin inhibitor (CNI) plus EVR. Median time posttransplantation was 33.06 months (interquartile range 18.25 to 42.85). Mean estimated glomerular filtration rate (eGFR) the first month posttransplantation (using Modification of Diet in Renal Disease formula) was 54.89 ± 19.08 mL/min, and mean proteinuria was 0.54 ± 0.38 g/24 h. At the end of follow up, mean eGFR and mean proteinuria significantly improved (65.49 ± 20.79 mL/min; P = .011 and 0.157 ± 0.089 g/24 h; P = .002, respectively). Group B consisted of 59 patients; 49 of them initially received mycophenolic acid (MPA) plus CNI, and 10 had been on azathioprine plus CNI. Initial immunosuppression was switched to MPA plus EVR in 49 patients, CNI plus EVR in 4 patients, and EVR in 6 patients, in a median time of 37 months (interquartile range 14.75 to 112.5) posttransplantation. Main indications for conversion were malignancies and biopsy-proven chronic allograft injury. Mean eGFR 1 month posttransplantation and at the time of conversion were 50.79 ± 17.83 mL/min and 57.39 ± 19.17 mL/min, respectively (P = .014). After conversion, mean eGFR increased (66 ± 24.89 mL/min; P = .006). Mean proteinuria was 0.509 ± 0.530 g/24 h the first posttransplantation month, and it remained stable at 0.415 ± 0.431 g/24 h until study completion. Two acute rejection episodes occurred. At the end of follow-up, patient and death-censored graft survival were 97% and 100%, respectively. CONCLUSIONS: In kidney transplant recipients, EVR either de novo or after conversion with or without CNI is a safe and effective treatment that preserves renal function.

The Importance of Novel Inflammatory Biomarkers in Renal Disease.

Kidney disease, whether acute or chronic, represents a major health hazard. Acute kidney injury (AKI) detection is based mainly on serum creatinine, which is considered to delay prompt diagnosis and management, thus increasing substantially patient morbidity and mortality and prolonged hospitalization. Several biomarkers have been evaluated as early prognostic markers of AKI. However, the vast majority of them are still far from being implicated into clinical practice. On the other hand, routine eGFR estimation and proteinuria monitoring have contributed to previous identification of chronic kidney disease (CKD). Hence, more sensitive and specific biomarkers are needed to enable us recognize individuals at increased risk for progression of CKD to end-stage renal disease (ESRD) and occurrence of cardiovascular complications. This review focuses on the most important novel inflammatory biomarkers that have emerged for early prediction, monitoring and management of kidney disease.

Glomerular disease recurrence in the renal allograft: a hurdle but not a barrier for successful kidney transplantation.

Almost all forms of primary as well as secondary glomerulonephritides may recur after renal transplantation. Recurrence of the original disease is now the third most common cause of late allograft loss. Nevertheless, in most cases it is difficult to assess the true impact of primary disease recurrence in the allograft; histological recurrence with mild features does not necessarily implicate clinically severe disease. Moreover it is often difficult to distinguish recurrent from de novo disease as in membranous glomerulopathy. Because recurrence occurs late, histological lesions of recurrent glomerulonephritis may be unmasked by chronic damage from other causes such as chronic rejection. Beside the difficulties to interpret renal histology due to the variety of allograft lesions, there are no well-established options to prevent clinically severe disease recurrence nor the therapeutic approaches to the problem. The purpose of this review was mainly to underline that almost all primary and secondary glomerulonephritides represent a contraindication to transplantation. For the majority of patients with end-stage renal disease due to glomerulonephritis, transplantation still represents the treatment of choice.

B cell depletion: rituximab in glomerular disease and transplantation.

B cells play a central role in the pathogenesis of many autoimmune diseases. Selective targeting can be achieved with the use of the monoclonal antibody rituximab. In addition to being a drug for non-Hodgkin's lymphoma, rituximab is also an FDA-approved treatment for refractory rheumatoid arthritis and, since recently, ANCA vasculitis. It has shown efficacy in many autoimmune diseases. This review will discuss current evidence and the rationale of the use of rituximab in glomerular diseases, including randomized controlled trials. The focus will be on the use of rituximab in idiopathic membranous nephropathy, systemic lupus erythematosus and ANCA-associated vasculitis. The emerging role of rituximab in renal transplantation, where it seems to be important for the desensitization protocols for highly sensitized patients as well as for the preconditioning of ABO-incompatible recipients and the treatment of antibody-mediated rejection, will also be addressed.

Mycophenolate mofetil as maintenance therapy in patients with vasculitis and renal involvement.

AIM: Cytotoxic drugs have reduced the mortality in patients with ANCA-associated vasculitis (AASV) but their use carries a substantial risk of toxicity. Efforts are made to switch from cytotoxic drugs to less toxic maintenance regimens. In this study we aimed to assess the efficacy of mycophenolate mofetil (MMF) as maintenance therapy in patients with AASV and renal involvement. METHODS: 22 patients with newly diagnosed AASV, microscopic polyangiitis (MPA) (n = 16), Wegener's granulomatosis (WG, n = 4), renal limited vasculitis (RLV, n = 1) and Churg-Strauss syndrome (CSS, n = 1) and renal involvement were followed for a median of 42 months (range 24 - 101). After 6 months of standard induction therapy, patients were switched to MMF monotherapy for 18 months. Renal parameters i.e. serum creatinine, proteinuria and urine sediment, BVAS scores and ANCA titers were assessed at baseline, after induction and after 18 months with MMF. RESULTS: After the end of induction, 3 of the 4 patients who were initially hemodialysis (HD) dependent, remained on HD and were withdrawn from further analysis. In the remaining 19 patients, the improvement in renal function (p < 0.001), hematuria (p = 0.011), proteinuria (p = 0.007) and BVAS scores (p < 0.001) after induction was sustained after 18 months maintenance with MMF and no patient relapsing during this period. Until the end of the follow up, 31.58% of patients relapsed, at a median of 21.5 months (range: 18 - 60). Side effects were transient and infrequent. CONCLUSION: In patients with AASV and renal involvement, MMF seems to be an effective and well tolerated option in sustaining short- and medium-term remission.

In vivo effects of cyclic administration of 15-deoxyspergualin on leucocyte function in patients with Wegener's granulomatosis.

15-Deoxyspergualin (DSG) is an alternative treatment modality for Wegener's granulomatosis (WG) patients refractory to conventional treatment. Nevertheless, it is unclear how DSG modulates disease activity in these patients. This study was conducted to investigate which parameters of adaptive and acquired immunity were influenced during two subsequent cycles of DSG treatment. Emphasis was put upon T cell and monocyte activation, neutrophil function and surface expression of proteinase-3 (PR-3). Anti-CD3/anti-CD28 and interleukin (IL)-15/IL-7-mediated T cell proliferation were assessed by fluorescence activated cell sorter (FACS) analysis using carboxyfluorescein succinimidyl ester (CSFE) labelling. Interferon (IFN)-gamma and IL-10 production were determined in the supernatants of these cultures by enzyme-linked immunosorbent assay. Monocyte activation was assessed in lipopolysaccharide (LPS)-stimulated whole blood, using tumour necrosis factor (TNF)-alpha as read-out. Neutrophil function was determined by measuring oxidative burst, chemotaxis and phagocytosis. T cell activation markers and PR3 expression were measured by FACS. All parameters were determined directly before and after each DSG cycle. Anti-CD3/anti-CD28-mediated T cell proliferation was reduced directly after DSG treatment. Directly before a subsequent cycle of DSG was started, T cell proliferation was increased. Similar findings were observed for IFN-gamma and IL-10 production by T cells. DSG did not influence IL-15/IL-7-mediated T cell proliferation. LPS-mediated TNF-alpha production was also impaired directly after DSG treatment. No influence on T cell activation markers, neutrophil function and surface PR-3 expression was observed in peripheral blood of these patients. Our data demonstrate that DSG influences T cell and monocyte activation in a reversible fashion. Although DSG causes neutropenia in these patients, it does not influence neutrophil function.

Abnormalities of CD4 T cell subpopulations in ANCA-associated vasculitis.

In patients with ANCA-associated vasculitis (AAV), CD25 expression is increased on circulating T cells. Although in animal experiments the role of CD4(+) CD25(+) T-regulatory-cells (T(reg)) in protection against autoimmunity is well established, the role of these cells in AAV is unknown. To investigate the hypothesis that an increased expression of CD25 on T cells is related to persistent T cell activation and not to disturbances in T(reg) cells in AAV (34 patients, six of them after renal transplantation), we investigated CD25 expression in different subpopulations of CD4(+) cells and FOXP3 mRNA expression by reverse transcription-polymerase chain reaction (RT-PCR). In addition, T cell proliferation and cytokine secretion after stimulation with anti-CD3 and anti-CD28 and intracellular cytokine production after stimulation with phorbol myristate acetate (PMA)-ionomycin was determined. Controls were non-vasculitic renal transplant patients (n = 9) and healthy controls (HC) (n = 13). In AAV the total number of lymphocytes, CD4(+) lymphocytes and the percentage of naive T cells are lower than in HC and RTX. An increased percentage of CD25(+) cells was found in AAV and AAV/RTX, irrespective of disease activity, but not in HC or RTX. This was confined to the naive (CD4(+) CD45RB(high)) population only. FOXP3 mRNA expression in CD4(+) T cells did not differ between AAV patients and healthy controls. In vitro T cell proliferation was enhanced in AAV patients compared to HC (P < 0.01). PBMC of AAV patients produced significantly less interleukin (IL)-10 and interferon (IFN)-gamma after anti-CD3/CD28 stimulation. The percentage of IL-10 and IL-12, but not IFN-gamma, IL-4 or tumour necrosis factor (TNF)-alpha-producing cells was significantly higher in patients compared to HC. These findings were confined to the memory population of CD4(+) cells. We conclude that AAV patients are lymphopenic and have low numbers of CD4(+) T cells, which seem to be in a persistent state of activation.

Altered CD46-mediated T cell co-stimulation in haemodialysis patients.

While most of our understanding of immune dysfunction in dialysis patients involves alterations in CD28-CD80/86 signalling, nothing is known of CD46-mediated co-stimulation of T cells in these patients. Because C3b/C4b bind to CD46 and complement activation occurs during haemodialysis (HD), we addressed whether CD46-mediated T cell activation is altered in HD (n = 9), peritoneal dialysis (PD) (n = 10) and predialysis patients (n = 8) compared to healthy controls (HC) (n = 8). T cell surface markers, T cell proliferation and interleukin (IL)-10 production were studied in CD4(+)T cells. In addition, CD46 splice-variants and IL-10 promoter gene polymorphisms were studied by reverse transcription (RT) or amplification refractory mutation system-polymerase chain reaction (ARMS-PCR), respectively. In all uraemic patients, irrespective of the stage of renal insufficiency or dialysis modality, a significant increase in the percentage of CD25 positivity in naive CD4(+)T cells was found (64% +/- 21%versus 23% +/- 18%, P < 0.001). Lymphocytes of HD patients proliferated in greater numbers and produced more IL-10 after co-stimulation with anti-CD46 than after co-stimulation with anti-CD28. This was also found in CD4(+)T cells of PD patients, albeit to a lesser extent. In contrast, with T cells of predialysis patients and of HC, co-stimulation via CD28 was more efficient. The observed alterations in T cell proliferation and IL-10 production were associated neither with CD46 splice variants nor with IL-10 promoter gene polymorphisms. Lymphocytes of HD patients show an increased response on CD46 co-stimulation. These data suggest that ongoing complement activation in HD patients may lead to alterations in acquired immunity.