Granulomatosis with polyangiitis (GPA) is an autoimmune disease affecting mainly small blood vessels. B-cells are important in the GPA pathogenesis as precursors of autoantibody-producing cells but ...likely also contribute (auto)antibody-independently. This has been underlined by the effectiveness of B-cell-depletion (with Rituximab) in inducing and maintaining disease remission. Mycophenolate-mofetil (MMF) and azathioprine (AZA) are immunosuppressive therapies frequently used in GPA-patients. Interestingly, MMF-treated GPA-patients are more prone to relapses than AZA-treated patients, while little is known about the influence of these drugs on B-cells. We investigated whether MMF or AZA treatment (or their active compounds) alters the circulating B-cell subset distribution and has differential effects on in vitro B-cell proliferation and cytokine production in GPA-patients that might underlie the different relapse rate. Circulating B-cell subset frequencies were determined in samples from AZA-treated (n = 13), MMF-treated (n = 12), untreated GPA-patients (n = 19) and matched HCs (n = 41). To determine the ex vivo effects of the active compounds of MMF and AZA, MPA and 6-MP respectively, on B-cell proliferation and cytokine production, PBMCs of untreated GPA-patients (n = 29) and matched HCs (n = 30) were cultured for 3-days in the presence of CpG-oligodeoxynucleotides (CpG) with MPA or 6-MP. After restimulation (with phorbol myristate acetate, calcium-ionophore), cytokine-positive B-cell frequencies were measured. Finally, to assess the effect of MMF or AZA treatment on in vitro B-cell proliferation and cytokine production, PBMCs of MMF-treated (n = 18), and AZA-treated patients (n = 28) and HCs (n = 41) were cultured with CpG. The memory B-cell frequency was increased in AZA- compared to MMF-treated patients, while no other subset was different. The active compounds of MMF and AZA showed in vitro that MPA decreased B-cell proliferation in GPA-patients and HCs. B-cell proliferation in MMF- and AZA-treated patients was not different. Finally, the IL-6.sup.+ B-cell frequency was decreased by MPA compared to 6-MP. No differences in IL-10.sup.+, IL-6.sup.+ or TNFalpha.sup.+ B-cell proportions or proliferation were found in MMF- and AZA-treated patients. Our results indicate that MMF could be superior to AZA in inhibiting B-cell cytokine production in GPA-patients. Future studies should assess the effects of these immunosuppressive drugs on other immune cells to elucidate mechanisms underlying the potential differences in relapse rates.
This study evaluated predictors for patient and renal survival in patients with ANCA-associated vasculitis (AAV) with and without renal involvement.
There were 273 consecutive AAV patients from ...January 1990 until December 2007 who were followed until death, loss to follow-up, or December 2010. Based on organ involvement, patients were divided into renal (n=212) and nonrenal groups (n=61). The primary end point was ESRD requiring renal replacement therapy (RRT) or renal transplantation or death.
Patient survival was significantly better in the nonrenal group compared with the renal group (hazard ratio, 0.55; 95% confidence interval, 0.33 to 0.92; P=0.02). In the renal group, renal survival was significantly worse in MPO-ANCA-positive patients (n=65) compared with PR3-ANCA-positive patients (n=138) (hazard ratio, 2.1; 95% confidence interval, 1.11 to 3.8; P=0.01). Of 48 patients who needed RRT at diagnosis, 11 patients (23%) died within 6 months and 14 patients (29%) did not regain renal function. Of all 23 patients who regained renal function after RRT, 7 patients (30%) were temporarily dialysis independent and needed dialysis later (range, 13-63 months). Five patients had a renal relapse in the 6 months before restart of RRT. Of all 203 PR3-ANCA-positive and MPO-ANCA-positive patients with renal involvement, 12 patients (6%) developed ESRD during follow-up. These patients were classified as CKD stage 4 or 5 after initial treatment and eight patients had a renal relapse before becoming dialysis dependent.
AAV patients with renal involvement who needed RRT had the worst survival probability. In multivariate analysis, the only major determinants for long-term renal survival were renal function at 6 months and renal relapses.
The antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) comprise granulomatosis with polyangiitis (GPA), primarily associated with antibodies to proteinase 3 (PR3-ANCA); ...microscopic polyangiitis (MPA); and eosinophilic granulomatosis with polyangiitis (EGPA), both principally associated with antibodies to myeloperoxidase (MPO-ANCA). Genetic and environmental factors are involved in their etiopathogenesis, with a possible role for silica exposure in AAVs and Staphylococcus aureus infection in GPA. The distinct associations of PR3-ANCA and MPO-ANCA with different HLA class II antigens, which are stronger than those with the associated diseases, suggest a pathogenic role for those ANCAs and indicate that GPA and MPA are different diseases. Both in vitro and in vivo experimental data have shown that MPO-ANCA can induce necrotizing small-vessel vasculitis and glomerulonephritis. The additional role of the alternative pathway of complement activation has been demonstrated in human and experimental pathology. Also, T cells seem to be involved in lesion development, particularly in the kidney. Granuloma formation, as seen in PR3-ANCA–associated GPA, is not well explained by the presence of autoantibodies in experimental models. Here, T cells seem crucial. Recently obtained insights into the pathogenesis of AAVs have led to more targeted treatment of these life-threatening diseases.
Kidney histopathology in lethal human sepsis Aslan, Adnan; van den Heuvel, Marius C; Stegeman, Coen A ...
Critical care (London, England),
12/2018, Letnik:
22, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The histopathology of sepsis-associated acute kidney injury (AKI) in critically ill patients remains an understudied area. Previous studies have identified that acute tubular necrosis (ATN) is not ...the only driver of sepsis-AKI. The focus of this study was to identify additional candidate processes that may drive sepsis-AKI. To do this we immunohistochemically characterized the histopathological and cellular features in various compartments of human septic kidneys.
We studied the following histopathological features: leukocyte subsets, fibroblast activation, cellular proliferation, apoptosis, and fibrin deposition in the glomerulus and the tubulointerstitium in human post-mortem kidney biopsy tissue. Biopsy tissue samples from 27 patients with sepsis-AKI were collected 33 min (range 24-150) after death in the ICU. The unaffected part of the kidneys from 12 patients undergoing total nephrectomy as a result of renal carcinoma served as controls.
Immunohistochemical analysis revealed the presence of more neutrophils and macrophages in the glomeruli and more neutrophils in the tubulointerstitium of renal tissue from patients with sepsis compared to control renal tissue. Type II macrophages were predominant, with some macrophages expressing both type I and type II markers. In contrast, there were almost no macrophages found in control kidneys. The number of activated (myo)fibroblasts was low in the glomeruli of sepsis-AKI kidneys, yet this was not observed in the tubulointerstitium. Cell proliferation and fibrin deposition were more pronounced in the glomeruli and tubulointerstitium of sepsis-AKI than in control kidneys.
The extensive heterogeneity of observations among and within patients emphasizes the need to thoroughly characterize patients with sepsis-AKI in a large sample of renal biopsy tissue from patients with sepsis.
Azathioprine is a widely used immunosuppressive drug. Genetic polymorphisms and activity of the enzyme thiopurine methyltransferase (TPMT) have been associated with azathioprine efficacy and toxicity ...in several populations. We investigated whether these associations also exist for ANCA associated vasculitis (AAV) patients, who receive azathioprine maintenance therapy after remission induction with cyclophosphamide.
207 AAV patients treated with cyclophosphamide induction and azathioprine maintenance therapy were included and followed for 60 months. TPMT genotype and tertiles of TPMT activity were compared to relapse free survival and occurrence of adverse events, particularly leukopenia. Multivariable regression was performed to account for confounders.
In univariable analysis, relapse free survival was not significantly associated with TPMT genotype (P = 0.41) or TPMT activity (P = 0.07), although it tended to be longer in lower tertiles of TPMT activity. There was no significant association of TPMT genotype and activity with occurrence of any adverse event. In multiple regression, leukocyte counts at the end of cyclophosphamide induction were related to risk of leukopenia during azathioprine therapy P<0.001; OR 0.54 (95% CI 0.43-0.68) and risk of relapse during follow-up P = 0.001; HR 1.17 (95% CI 1.07-1.29) irrespective of TMPT genotype or activity.
TPMT genotype and activity were not independent predictors of relapse, and could not predict leukopenia or other adverse effects from azathioprine. Leukocyte counts after cyclophosphamide induction were related to both outcomes, implying a greater influence of cyclophosphamide response compared to azathioprine and TPMT in AAV patients.
Toll-like receptors (TLRs) are a family of receptors that sense pathogen associated patterns such as bacterial cell wall proteins. Bacterial infections are associated with anti-neutrophil cytoplasmic ...antibodies (ANCA)-associated vasculitis (AAV). Here, we assessed the expression of TLRs 2, 4, and 9 by peripheral blood leukocytes from patients with AAV, and investigated TLR mediated responses ex vivo.
Expression of TLRs was determined in 38 AAV patients (32 remission, 6 active disease), and 20 healthy controls (HC). Membrane expression of TLRs 2, 4, and 9, and intracellular expression of TLR9 by B lymphocytes, T lymphocytes, NK cells, monocytes and granulocytes was assessed using 9-color flowcytometry. Whole blood from 13 patients and 7 HC was stimulated ex vivo with TLR 2, 4 and 9 ligands and production of cytokines was analyzed.
In patients, we observed increased proportions of TLR expressing NK cells. Furthermore, patient monocytes expressed higher levels of TLR2 compared to HC, and in a subset of patients an increased proportion of TLR4(+) monocytes was observed. Monocytes from nasal carriers of Staphylococcus aureus expressed increased levels of intracellular TLR9. Membrane expression of TLRs by B lymphocytes, T lymphocytes, and granulocytes was comparable between AAV patients and HC. Patients with active disease did not show differential TLR expression compared to patients in remission. Ex vivo responses to TLR ligands did not differ significantly between patients and HC.
In AAV, monocytes and NK cells display increased TLR expression. Increased TLR expression by these leukocytes, probably resulting from increased activation, could play a role in disease (re)activation.
Oxalate nephropathy, due to secondary hyperoxaluria has widely been described in gastrointestinal diseases. However, reports of oxalate nephropathy in newly diagnosed celiac disease are rare. A ...72-year-old Caucasian male presented to the hospital with abdominal discomfort and acute renal insufficiency with a creatinine of 290 µmol/L. The clinical course, laboratory results and urinalysis were suspect for tubular injury. Renal biopsy showed calcium oxalate depositions. Elevated plasma and urine oxalate levels established the diagnosis oxalate nephropathy. The abdominal complaints with steatorrhea and positive anti-tissue transglutaminase antibodies were diagnosed as celiac disease, which was confirmed after duodenal biopsies. Treatment with prednisone, and gluten-free, low oxalate and normal calcium diet, lowered the plasma oxalate levels and improved his renal function. Decreased absorption of free fatty acids can lead to increased free oxalate in the colon due to the binding of free fatty acids to calcium, preventing the formation of the less absorbable calcium oxalate in the colon. Oxalate dispositions in the kidney can lead to acute tubular injury and chronic renal insufficiency. Celiac disease is therefore one of the intestinal diseases that can lead to hyperoxaluria and oxalate nephropathy.
Anti-neutrophil cytoplasmic antibody-associated (ANCA-associated) small vessel necrotizing vasculitis is caused by immune-mediated inflammation of the vessel wall and is diagnosed in some cases by ...the presence of myeloperoxidase-specific antibodies (MPO-ANCA). This multicenter study sought to determine whether differences in ANCA epitope specificity explain why, in some cases, conventional serologic assays do not correlate with disease activity, why naturally occurring anti-MPO autoantibodies can exist in disease-free individuals, and why ANCA are undetected in patients with ANCA-negative disease. Autoantibodies from human and murine samples were epitope mapped using a highly sensitive epitope excision/mass spectrometry approach. Data indicated that MPO autoantibodies from healthy individuals had epitope specificities different from those present in ANCA disease. Importantly, this methodology led to the discovery of MPO-ANCA in ANCA-negative disease that reacted against a sole linear sequence. Autoantibodies against this epitope had pathogenic properties, as demonstrated by their capacity to activate neutrophils in vitro and to induce nephritis in mice. The confounder for serological detection of these autoantibodies was the presence of a fragment of ceruloplasmin in serum, which was eliminated in purified IgG, allowing detection. These findings implicate immunodominant epitopes in the pathology of ANCA-associated vasculitis and suggest that autoantibody diversity may be common to other autoimmune diseases.
Physical quality of life is reduced in ANCA-associated vasculitis (AAV). This study aims to investigate whether this may be explained by reduced muscle strength and physical activity resulting from ...disease damage and steroid myopathy.
Forty-eight AAV patients were sequentially included from the outpatient clinic. Patients in different stages of disease and treatment underwent measurements of muscle strength and anthropometric parameters. Patients filled in physical activity (Baecke) and quality of life questionnaires (RAND-36) and carried an accelerometer for a week. Muscle strength and physical activity were compared to quality of life, prednisolone use and disease duration.
Most AAV patients had lower knee extension (76%) and elbow flexion (67%) forces than expected based on healthy norms. Also, physical (P<0.001) and mental (P = 0.01) quality of life were significantly reduced compared to healthy norm values. Lower knee extension force (P = 0.009), younger age <70 (P<0.001) and relapse of vasculitis (P = 0.003) were associated with lower age-adjusted physical quality of life. Lower Baecke index (P = 0.006), higher prednisolone dose (P = 0.005) and ENT involvement (P = 0.006) were associated with lower age-adjusted mental quality of life. Leg muscle strength showed no association with current or cumulative prednisolone use. Disease duration was longer in patients with knee extension force below healthy norms (P = 0.006).
Knee extension force and physical activity are positively associated with quality of life in AAV. Knee extension force decreases with longer disease duration, suggesting that disease- and treatment-related damage have a cumulative negative effect on muscle strength.
Wegener's granulomatosis and microscopic polyangiitis are antineutrophil cytoplasm antibodies (ANCA)-associated vasculitides with significant morbidity and mortality. The long-term survival of ...patients with ANCA associated vasculitis treated with current regimens is uncertain.
To describe the long-term patient survival and possible prognostic factors at presentation in an international, multicentre, prospectively recruited representative patient cohort who were treated according to strictly defined protocols at presentation and included the full spectrum of ANCA-associated vasculitis disease.
Outcome data were collected for 535 patients who had been recruited at the time of diagnosis to four randomised controlled trials between 1995 and 2002. Trial eligibility was defined by disease severity and extent, covered the spectrum of severity of ANCA-associated vasculitis and used consistent diagnostic criteria. Demographic, clinical and laboratory parameters at trial entry were tested as potential prognostic factors in multivariable models.
The median duration of follow-up was 5.2 years and 133 (25%) deaths were recorded. Compared with an age- and sex-matched general population there was a mortality ratio of 2.6 (95% CI 2.2 to 3.1). Main causes of death within the first year were infection (48%) and active vasculitis (19%). After the first year the major causes of death were cardiovascular disease (26%), malignancy (22%) and infection (20%). Multivariable analysis showed an estimated glomerular filtration rate <15 ml/min, advancing age, higher Birmingham Vasculitis Activity Score, lower haemoglobin and higher white cell count were significant negative prognostic factors for patient survival.
Patients with ANCA-associated vasculitis treated with conventional regimens are at increased risk of death compared with an age- and sex-matched population.
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