Anti-ETAR and suPAR as markers of disease activity in renal ANCA-associated vasculitis.

PURPOSE: In anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV), there is a lack of reliable biomarkers of disease activity. The aim of the study was to evaluate soluble urokinase plasminogen activator receptor (suPAR) and anti-endothelin-1 type A receptor (anti-ETAR) antibodies levels in active phase and remission of AAV. PATIENTS AND METHODS: We enrolled 60 patients (median age 63.0 years) with renal AAV into this study. Plasma suPAR, urine suPAR (expressed as urine suPAR/creatinine ratio) and serum anti-ETAR antibodies were assayed by ELISA. Disease activity was assessed using Birmingham Vasculitis Activity Score (BVAS) and patients were divided into 2 subgroups based on their BVAS scores, namely: active AAV subgroup (BVAS≥1) and remission subgroup (BVAS â€‹= â€‹0). Median follow-up was 12 months. RESULTS: Patients with active AAV had higher levels of all candidate biomarkers in comparison to those in remission (p â€‹< â€‹0.05). C-statistics for plasma suPAR, urine suPAR/creatinine ratio and serum anti-ETAR were 0.807, 0.713 and 0.783, respectively. In multivariable analysis, no clear associations were found between serum anti-ETAR and BVAS, while both plasma suPAR and serum anti-ETAR were independently influenced by estimated glomerular filtration rate (eGFR). CONCLUSIONS: Plasma suPAR better discriminated between active AAV and remission in comparison to urine suPAR/creatinine ratio and serum anti-ETAR antibodies.

Toll-like 4 receptor (TLR4) expression on peripheral blood mononuclear cells in renal transplant recipients with pre-transplant chronic interstitial nephritis indicates patients at risk of graft deterioration.

Data binding the expression of Toll-like 4 receptor (TLR4ex), transplanted kidney function, and the cause of pre-transplant end-stage renal disease are scarcely available. OBJECTIVE: To investigate the relationship between pre-transplant chronic interstitial nephritis (CIN), TLR4ex and transplanted kidney function. MATERIALS AND METHODS: TLR4ex was measured in peripheral blood mononuclear cells of 43 CIN kidney transplant recipients. We compared TLR4ex among 33 patients with pre-transplant chronic non-infectious interstitial nephritis (NIN) and 10 patients with pre-transplant chronic pyelonephritis (Py). At the beginning (Day-0) TLR4ex, as well as concentrations of cyclosporin A (CyA) and tacrolimus (TAC) were determined. Both CIN and NIN patients were divided according to the respective median of TLR4ex into groups of low-TLR4 expression (L-TLR4ex) and high-TLR4 expression (H-TLR4ex). Serum creatinine/glomerular filtration rate (sCr/EGFR) was assessed on Day-0 and after the follow-up (F-up). The magnitudes of sCr/EGFR change (ΔsCr/ΔEGFR) were evaluated. The treatment was maintained stable along the F-up period (median 11.9 months). RESULTS: Day-0: in CIN with L-TLR4ex TAC was lower but sCr/EGFR were not different from H-TLR4ex; in Py TLR4ex and TAC were lower than in NIN with no difference in sCR/eGFR. After F-up: in CIN with L-TLR4ex sCR/EGFR and ΔsCr/ΔEGFR were worse than in H-TLR4ex; in Py sCR/EGFR and ΔsCr/ΔEGFR were worse than in NIN. The regression analysis points out prospective impact of Py and TLR4ex on sCR/eGFR and ΔsCr/ΔeGFR. CONCLUSION: In CIN, both TLR4ex and Tac appear to be a useful positive predictor of the effectiveness of immunosuppression. Chronic pyelonephritis indirectly promotes faster progression of chronic transplanted kidney disease.

Post-transplant Alternative Complement Pathway Activation Influences Kidney Allograft Function.

The complement system is one of the crucial pathophysiological mechanisms that directly influence the function of a transplanted kidney. Since the complement pathways' activation potential can be easily determined via their functional activity measurement, we focused on fluctuation in the cascade activity in the early post-transplant period. The aim of the study was to relate the kidney transplantation-induced complement system response to allograft outcome. Forty-two kidney recipients (aged: 53.5 [37-52], 17 females/25 males) and 24 healthy controls (aged: 40.5 [34-51], 13 females/11 males) were enrolled in the study. The functional activities of alternative, classical, and lectin pathways were determined before and in the first week after transplantation using Wielisa®-kit. We observed that the baseline functional activity of the alternative pathway (AP) was higher in chronic kidney disease patients awaiting transplantation compared to healthy controls and that its level depended on the type of dialysis. AP-functional activity was decreased following transplantation procedure and its post-transplant level was related to allograft function. The baseline and transplantation-induced functional activities of the classical and lectin pathways were not influenced by dialysis type and were not associated with transplant outcome. Moreover, our study showed that intraoperative graft surface cooling had a protective effect on AP activation. Our study confirms the influence of dialysis modality on persistent AP complement activation and supports the role of AP in an early phase after kidney transplantation and allograft outcome.

High Prevalence of Autoantibodies Against Monomeric C Reactive Protein (CRP) in Children with PFAPA Syndrome.

PFAPA (periodic fever, aphthous stomatitis, pharyngitis, cervical adenitis) syndrome is an autoinflammatory disorder of unknown etiology. The aim of our study was to evaluate whether the presence of anti-mCRP autoantibodies (anti-mCRP) might possibly contribute to systemic inflammation during PFAPA flares. We carried out anti-mCRP testing (in-house ELISA) in a single-center, prospective cohort of 30 PFAPA patients (12 girls). We found a high prevalence (43.3%) of anti-mCRP antibodies in PFAPA patients during their febrile episodes, which implies the possible involvement of anti-mCRP antibodies in PFAPA pathogenesis.

Antibodies against monomeric C-reactive protein - a promising biomarker of lupus nephritis?

OBJECTIVE AND AIM: A significant incidence of systemic lupus erythematosus (SLE), the severity of lupus nephritis and varying responses to treatment rationalize the search for novel biomarkers of disease activity. The aim of the study was to assess whether antibodies against monomeric C reactive protein (anti-mCRP) are associated with the presence of lupus nephritis, correlate with disease activity, and whether they can serve to evaluate a response to treatment. METHODS: The study involved 74 patients with lupus nephritis, 29 patients with systemic lupus without renal involvement and 31 patients with primary glomerulonephritis; the control group included 31 healthy volunteers. Interleukin-6 and tumor necrosis factor alpha were measured using commercially available ELISA tests. The presence of anti-mCRP in the serum was tested with the use of in-house ELISA. RESULTS: The highest prevalence and concentrations of antibodies against monomeric C-reactive protein were observed among patients with lupus nephritis, as compared to other groups. The elevated level of anti-mCRP was associated with standard clinical and laboratory indicators of SLE activity. Moreover, the highest concentrations of both Il-6 and TNF-α were observed for patients with the most severe nephropathy. A significant decrease in anti-mCRP and cytokines' levels in the course of treatment was observed. CONCLUSION: The study gives further evidence that antibodies against monomeric C-reactive protein may be considered an indicator of renal involvement in patients with SLE. Assessment of anti-mCRP supports monitoring of disease activity and can be used in evaluating the treatment effectiveness.

Immune activation- and regulation-related patterns in stable hand transplant recipients.

We assessed cell subsets and expression of a set of genes related to the T-cell populations in peripheral blood mononuclear cells to elucidate whether immune status of stable hand transplant recipients (HTx) differs from stable kidney transplant recipients (KTx). The study was conducted on five HTx 4.8 ± 1.7 years after transplantation and 30 stable KTx 7.9 ± 2.4 years after transplantation as well as 18 healthy volunteers. The research involved PBMC gene expression analysis of CD4, CD8, CTLA4, GZMB, FOXP3, IL10, IL4, ILR2A, NOTCH, PDCD1, PRF1, TGF-B, and TNF-A genes on a custom-designed low-density array (TaqMan) as well as flow cytometry assessment of lymphocyte subpopulations. HTx presented significantly increased expression of immunomodulatory genes (TNF, IL10, GITR, and PDCD1) compared to KTx and controls. HTx revealed a proinflammatory molecular pattern with higher expression of NOTCH and CD8 compared to KTx and controls. KTx showed a reduced level of regulatory T cells compared to controls and HTx. Both HTx and KTx presented an increased number of CD8+ and CD8+ CD28- T cells compared to controls. Stable hand transplant recipients exhibit persistent immune activation with rejection-related gene expression pattern counterbalanced by secondary induction of regulatory mechanisms.

The influence of warm ischemia elimination on kidney injury during transplantation - clinical and molecular study.

Kidney surface cooling was used during implantation to assess the effect of warm ischemia elimination on allograft function, histological changes and immune-related gene expression. 23 recipients were randomly assigned to a group operated on with kidney surface cooling during implantation (ice bag technique, IBT group), and the other 23 recipients receiving the contralateral kidney from the same donor were operated on with a standard technique. Three consecutive kidney core biopsies were obtained during the transplantation procedure: after organ recovery, after cold ischemia and after reperfusion. Gene expression levels were determined using low-density arrays (Format 32, TaqMan). The IBT group showed a significantly lower rate of detrimental events (delayed graft function and/or acute rejection, p = 0.015) as well as higher glomerular filtration rate on day 14 (p = 0.026). A greater decrease of MMP9 and LCN2 gene expression was seen in the IBT group during total ischemia (p = 0.003 and p = 0.018). Elimination of second warm ischemia reduced the number of detrimental events after kidney transplantation, and thus had influence on the short-term but not long-term allograft function. Surface cooling of the kidney during vascular anastomosis may reduce some detrimental effects of immune activation resulting from both brain death and ischemia-reperfusion injury.

CD4(+)CD25(+)CD127(-) and CD4(+)CD25(+)Foxp3(+) Regulatory T Cell Subsets in Mediating Autoimmune Reactivity in Systemic Lupus Erythematosus Patients.

UNLABELLED: The available clinical as well as experimental studies implicate participation of T regulatory (Treg) subsets in the pathogenesis and course of systemic lupus erythematosus (SLE). Introduction of the CD4(+)CD25(+)CD127(-) and CD4(+)CD25(+)Foxp3(+) regulatory subpopulations analysis into immunological processes assessment and disease activation prognosis in patients with lupus nephritis (LN) may improve monitoring of disease activity and enable an early, and thus more effective, therapeutic treatment. The main goal of the study was to investigate whether the quantitative changes of Treg subpopulations are related to the clinical status of patients with LN. Fifty-four adult SLE patients divided into two groups according to their SLEDAI and renal SLEDAI scores were enrolled into the study. Subpopulations of CD4(+)CD25(+)CD127(-) and CD4(+)CD25(+)Foxp3(+) phenotypes were determined by flow cytometry. The control group had higher absolute number of CD4(+)CD25(+)Foxp3(+) cells compared with the study group (p < 0.001). Also, significant inverse correlation in the absolute number of CD4(+)CD25(+)Foxp3(+) cells and SLEDAI score was observed. There were significant differences in the percentage and absolute number of CD4(+)CD25(+)Foxp3(+) lymphocytes between active and non-active LN groups. The study group had statistically lower values of CD4(+)CD25(+)CD127(-) cells, both in the percentage (p < 0.001) as well as their absolute number (p = 0.014) compared to the control group. There were also statistically significant positive correlations between the absolute number of CD4(+)CD25(+)CD127(-) and CD4(+)CD25(+)Foxp3(+) Tregs. IN CONCLUSION: (1) reduction in the number of regulatory CD4(+)CD25(+)Foxp3(+) cells is a promising indicator of the activity of SLE, particularly of renal involvement; (2) determination of the number of regulatory cells using the CD4(+)CD25(+)CD127(-) phenotype is unreliable in patients with SLE.

[The immunomodulatory role of Vitamin D]. / Immunomodulacyjne dzialanie witaminy D.

The vitamin D endocrine system plays a crucial role in regulation of calcium homeostasis and bone metabolism. Over the past two decades of research, there is a growing appreciation for the immunoregulatory role of vitamin D. Vitamin D deficiency is associated with numerous diseases characterized by inflammation, including malignancies, autoimmune disorders and chronic infections. Vitamin D suppresses parathyroid hormone secretion, adaptive immune response, cell proliferation, and at the same time promotes insulin secretion, innate immune response and stimulates cell differentiation. The review discusses present state of knowledge of a basic role of vitamin D in modulating different immunological properties, including lymphocyte activation and proliferation, differentiation of Th lymphocytes, production of specific antibodies and regulation of the immune response. Finally, clinical potential of vitamin D metabolites for modulating tissue-specific immune responses and for preventing and treating inflammatory disease and immune system disorders has been reported.

The influence of non-HLA antibodies directed against angiotensin II type 1 receptor (AT1R) on early renal transplant outcomes.

Non-HLA antibodies (Abs) targeting vascular receptors are thought to have an impact on renal transplant injury. Anti-angiotensin II type 1-receptor-activating antibodies (anti-AT1R) have been mentioned to stimulate a severe vascular rejection, but the pretransplant screening has not been introduced yet. The aim of our study was to assess the incidence and importance of anti-AT1R antibodies and their influence on renal transplant in the 1st year of observation. We prospectively evaluated the presence of anti-AT1R antibodies in 117 consecutive renal transplant recipients in pre- and post-transplant screening. Anti-AT1R antibodies were observed in 27/117 (23%) of the analyzed recipients already before transplantation. The function of renal transplant was considerably worse in anti-AT1R(+) group. The patients with anti-AT1R Abs >9 U/ml lost their graft more often. Biopsy-proven AR was described in 4/27 (15%) pts in the anti-AT1R(+) group and 13/90 (14.4%) in the anti-AT1R(-) group, but more severe cases of Banff IIB or antibody-mediated rejection (AMR) were more often observed in anti-AT1R (+) 4/27 (15%) vs. 1/90 (1.1%) in anti-AT1R(+) (P = 0.009). Patients with anti-AT1R Abs level >9 U/ml run a higher risk of graft failure independently of classical immunological risk factors. The recipients with anti-AT1R Abs developed more severe acute rejections described as IIB or AMR in Banff classification. More recipients among the anti-AT1R-positive ones lost the graft. Our study suggests monitoring of anti-AT1R Abs before renal transplantation for assessment of immunologic risk profiles and the identification of patients highly susceptible to immunologic events, graft failure, and graft loss.

The impact of non-HLA antibodies directed against endothelin-1 type A receptors (ETAR) on early renal transplant outcomes.

BACKGROUND: Non-HLA antibodies (Abs) targeting vascular receptors are considered to have an influence on renal transplant injury. Anti-endothelin-1 type A receptor (anti-ETAR) antibodies were associated with cellular and antibody-mediated rejection and early onset of vasculopathy in heart transplant patients but their role in renal transplantation remains unclear. The aim of our study was to assess the incidence and importance of anti-ETAR antibodies and their impact on renal transplant during the first year observation. METHODS: We evaluated the presence of anti-ETAR antibodies in 116 consecutive renal transplant recipients in pre- and post-transplant screening (before and in 1st, 3rd, 6th, 12th month after transplantation). Additionally, we assessed the presence of anti-HLA antibodies. Anti-ETAR antibodies were assayed by ELISA. The diagnosis of acute rejection was based on the Banff criteria. RESULTS: Anti-ETAR antibodies were observed in 55 (47.4%) of the analyzed recipients before transplantation. The function of renal transplant was significantly worse in the anti-ETAR(+) group compared to the anti-ETAR(-) group during the first post-transplant year. One month after transplantation the serum creatinine in anti-ETAR (+) patients (pts) was 1.86±0.8mg/dl and 1.51±0.5 in anti-ETAR(-) pts (p=0.009). Twelve months after transplantation the difference between the groups was still observed 1.70±0.7 vs. 1.40±0.4 (p=0.04). Biopsy proven acute rejection was recognized in 8/55 (14.5%) in ETAR(+) and 9/61 (14.8%) in ETAR(-) patients but cases with mild to severe intimal arteritis (v1-v3) were more often observed in patients with the presence of anti-ETAR Abs 4/55 (7.2%) comparing with 1/61 (1.6%) in anti-ETAR(-) patients. The anti-ETAR antibody levels varied at different measurement intervals during the one-year follow-up. CONCLUSIONS: The presence of anti-ETAR antibodies is associated with a worse renal transplant function during the first 12months after transplantation. Including anti-ETAR antibodies in the diagnostics of renal transplant recipient immune status should be considered to provide comprehensive assessment of humoral alloimmunity.

The complement cascade and renal disease.

Serum complement cascade, a part of innate immunity required for host protection against invading pathogens, is also a mediator of various forms of disease and injury. It is activated by classical, lectin, and alternative pathways that lead to activation of C3 component by C3 convertases, release of C3b opsonin, C5 conversion and eventually membrane attack complex formation. The tightly regulated activation process yields also C3a and C5a anaphylatoxins, which target a broad spectrum of immune and non-immune cells. The review discusses the involvement of the complement cascade in kidney disease pathogenesis and injury. The role of the complement pathways in autoantibody-mediated forms of glomerulonephritis (lupus nephritis, anti-glomerular basement membrane disease, anti-neutrophil cytoplasmic autoantibody-induced or membranoproliferative glomerulonephritis, membranous nephropathy), C3 glomerulopathy, atypical forms of hemolytic uremic syndrome, ischemic-reperfusion injury of transplanted kidney, and antibody-mediated renal allograft rejection are discussed. The disturbances in complement activation and regulation with underlying genetics are presented and related to observed pathology. Also promising strategies targeting the complement system in complement-related disorders are mentioned.