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Antineutrophil cytoplasmic autoantibodies (ANCA) associated vasculitis (AAV) consists of a group of systemic autoimmune diseases. The roles of serum anti-nuclear antibodies (ANA) and anti-double-stranded DNA (anti-dsDNA) antibodies in AAV patients remain unknown. This study investigated the prevalence of serum ANAs and anti-dsDNA antibodies in AAV patients and characterized the clinical and pathological features of these patients. A total of 218 AAV patients were enrolled. Clinical and pathological data of patients were analyzed retrospectively. Of the 218 AAV patients, 109 (50.0%) were positive for ANA, 45 (20.6%) were positive for anti-dsDNA, and 43 (19.7%) were positive for both. The AAV patients with ANA had severer kidney damage and more chronic renal histopathological changes compared to those who were negative for ANA. Specifically, patients positive for ANA had more hypertension, higher levels of urea nitrogen and serum creatinine, lower estimated glomerular filtration rate (eGFR), more end-stage renal disease (ESRD), severer proteinuria, glomerular sclerosis, tubular interstitial fibrosis and tubular atrophy, and were more likely to receive renal biopsies compared to ANA negative patients. The study found ANA and anti-dsDNA in AVV patients were not rare, ANA-positive AAV patients had severer kidney damage and more chronic renal histopathological changes compared to ANA-negative AAV patients. Renal biopsy is strongly recommended for differential diagnosis in such cases.

Background There are reports of circulating antineutrophil cytoplasmic autoantibodies (ANCA) in patients with immunoglobulin A (IgA) nephropathy with an uncertain pathogenic role. Aim of the work To present the findings of myeloperoxidase (MPO) ANCA-positive patients amid a different course of IgA nephropathy with crescents and to discuss the efficacy of immunosuppressive therapy. Case presentation Two cases of IgA nephropathy associated with positive ANCA are reported and a review of the literature data is presented. The first patient presented with a progressive nephropathy and significantly impaired renal function at baseline, whereas in the second patient renal function remained stable over 10 years, despite the recurrent exacerbations of the disease. Both patients had extrarenal manifestations (joint pain and/or anemia) and elevated markers of inflammation (erythrocyte sedimentation rate, C-reactive protein) that are not typical features for IgA nephropathy. In the first case, immunosuppressive therapy with corticosteroids and cyclophosphamide resulted in improvement of kidney function. The second case showed the potential efficacy of rituximab as an induction remission and maintenance therapy for ANCA-positive IgA nephropathy. Conclusion Whether the association of IgA nephropathy with ANCA positivity is coincidental or constitutes a novel entity remains debated. Circulating ANCA can be found in patients with IgA nephropathy. They can be truly pathogenic and contribute to kidney damage and may induce overt systemic vasculitis or at least extrarenal signs and symptoms. ANCA-positive IgA nephropathy can respond to immunosuppressive regimens, including rituximab, similar to patients with ANCA-associated vasculitis (AAV).

Nefropatía por IgA; Autoanticuerpos anticitoplasma de neutrófilos IgA nephropathy; Antineutrophil cytoplasmic autoantibodies Nefropatia per IgA; Anticossos anticitoplasma de neutròfils Background: Immunoglobulin A nephropathy (IgAN) is the most common glomerulonephritis worldwide. The concomitant presence of both crescentic proliferation and anti-neutrophil cytoplasmic autoantibodies (ANCA) in this pathology represents a rare coincidence. However, it is not clear to what extent the presence of ANCA (IgA or IgG) in these patients could have any clinical significance. The aim of the current work is to describe the presence of ANCA (IgA or IgG) in patients with IgAN and crescentic proliferation and its possible clinical implications. Methods: We retrospectively recruited all patients in our center with a histological diagnosis of IgAN with crescentic proliferation between January 2013 and December 2020. The main demographic and clinicopathologic data, fundamental histological characteristics, as well as the treatments implemented and main kidney outcomes, were collected and analyzed at a 6 and 12-month follow-up. Results: Between January 2013 and December 2020, a total of 17 adults were diagnosed with concomitant crescentic proliferation through a kidney biopsy of IgAN. Five (29.4%) patients showed ANCA, three (60%) showed IgA-ANCA and two (40%) showed IgG-ANCA. All ANCA-positive patients had some degree of crescentic proliferation. At diagnosis, the mean age of patients was 48 years old (range: 27–75). Nine of them were women (52%) and the most common clinical presentation was hypertension (71%). At the time of biopsy, the mean serum creatinine and proteinuria were 2.2 mg/dL (DS 1.42) and 3.5 g/mgCr (DS 1.22), respectively, with no statistical differences between ANCA-positive and -negative patients. Histological analyses showed that 11 out of the 12 (91%) ANCA-negative IgAN patients displayed less than 25% cellular crescents, whereas 100% of ANCA-positive IgAN patients displayed more than 25% cellular crescents (p = 0.04). Notably, five (30%) patients displayed fibrinoid necrosis, with four of them (80%) being IgAN-ANCA-positive (p = 0.01). Only one ANCA-negative patient needed renal replacement therapy (RRT) upon admission (5%). The mean serum creatinine and proteinuria were 1.94 mg/dL (DS 1.71) and 1.45 g/gCr (DS 1.78), respectively, within 6 months of immunosuppressive therapy. At 12-month follow-up, the mean creatinine was 1.57 mg/dL (DS 1). Four (23.5%) patients needed RRT at the end of the follow-up and four (23.5%) patients died. Conclusions: Probably due to the limited number of IgAN-ANCA-positive and IgAN-ANCA-negative patients, no significant differences were found between the clinical and laboratory characteristics. IgAN-ANCA-negative patients seemed to display less extracapillary proliferation than IgAN-ANCA-positive patients, who tended to show significantly higher fibrinoid necrosis. There were no differences regarding renal prognosis and patient survival after aggressive immunosuppressive therapy within 6 and 12 months when comparing the two samples.

Background: PR3-ANCA, the serological marker of granulomatosis with polyangiitis (GPA), is usually detected by immunometric assays, with purified PR3 directly coated onto the solid-phase. Novel methods for PR3-ANCA detection have been developed to improve the performance of traditional PR3-ANCA specific assays, but little is known about their diagnostic performance in real-life clinical settings. This study aimed to compare the performance of nine different commercial PR3-ANCA specific assays, including traditional and newer ones, for the diagnosis of GPA. Methods: The evaluated assays for PR3-ANCA detection were representative of the first, second, and third generation tests (direct, capture and anchor assays, respectively). A third-generation assay employing both human and recombinant PR3 was also evaluated. The study population consisted of 55 GPA patients, 175 disease controls (representing most diseases in differential diagnosis with primary small-vessel vasculitis) including 52 with microscopic polyangiitis, and 20 healthy subjects. We performed the primary evaluation of test sensitivity using cut-off points which provided adequate and identical specificity for each test. Results: Although specificity and area under the ROC curve did not differ significantly between the different assays, substantial differences in sensitivity at 98%-specificity were found in some instances (p Conclusions: Some of the newer PR3-ANCA specific assays have better PPV than traditional ones.

Informamos el caso de un hombre de 79 años con hemorragia alveolar, glomerulonefritis necrosante y polineuropatía por poliangiítis microscópica, una enfermedad autoinmune, caracterizada por vasculitis sistémica, predominantemente de vasos de pequeño calibre. Se revisan los aspectos clínicos y terapéuticos de la enfermedad. We report the case of a 79 years-old male, with alveolar hemorrhage, necrotizing glomerulonephritis and polyneuropathy due to microscopic polyangiitis, an autoimmune disease, characterized by systemic vasculitis, predominantly of small vessels. We review the clinical and therapeutic aspects of the disease.

Autoimmune hepatitis (AIH) is a chronic necroinflammatory disease of the liver characterized by hypergammaglobulinemia, characteristic autoantibodies, association with HLA DR3 or DR4 and a favorable response to immunosuppressive treatment. The etiology is unknown. The detection of non-organ and liver-related autoantibodies remains the hallmark for the diagnosis of the disease in the absence of viral, metabolic, genetic, and toxic etiology of chronic hepatitis or hepatic injury. The current classification of AIH and the several autoantibodies/target-autoantigens found in this disease are reported. Current aspects on the significance of these markers in the differential diagnosis and the study of pathogenesis of AIH are also stated. AIH is subdivided into two major types; AIH type 1 (AIH-1) and type 2 (AIH-2). AIH-1 is characterized by the detection of smooth muscle autoantibodies (SMA) and/or antinuclear antibodies (ANA). Determination of antineutrophil cytoplasmic autoantibodies (ANCA), antibodies against the asialoglycoprotein receptor (anti-ASGP-R) and antibodies against to soluble liver antigens or liver-pancreas (anti-SLA/LP) may be useful for the identification of patients who are seronegative for ANA/SMA. AIH-2 is characterized by the presence of specific autoantibodies against liver and kidney microsomal antigens (anti-LKM type 1 or infrequently anti-LKM type 3) and/or autoantibodies against liver cytosol 1 antigen (anti-LC1). Anti-LKM-1 and anti-LKM-3 autoantibodies are also detected in some patients with chronic hepatitis C (HCV) and chronic hepatitis D (HDV). Cytochrome P450 2D6 (CYP2D6) has been documented as the major target-autoantigen of anti-LKM-1 autoantibodies in both AIH-2 and HCV infection. Recent convincing data demonstrated the expression of CYP2D6 on the surface of hepatocytes suggesting a pathogenetic role of anti-LKM-1 autoantibodies for the liver damage. Family 1 of UDP-glycuronosyltransferases has been identified as the target-autoantigen of anti-LKM-3. For these reasons the distinction between AIH and chronic viral hepatitis (especially of HCV) is of particular importance. Recently, the molecular target of anti-SLA/LP and anti-LC1 autoantibodies were identified as a 50 kDa UGA-suppressor tRNA-associated protein and a liver specific enzyme, the formiminotransferase cyclodeaminase, respectively. Anti-ASGP-R and anti-LC1 autoantibodies appear to correlate closely with disease severity and response to treatment suggesting a pathogenetic role of these autoantibodies for the hepatocellular injury. In general however, autoantibodies should not be used to monitor treatment, predict AIH activity or outcome. Finally, the current aspects on a specific form of AIH that may develop in some patients with a rare genetic syndrome, the autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED) are also given. Autoantibodies against liver microsomes (anti-LM) are the specific autoantibodies detected in AIH as a disease component of APECED but also in cases of dihydralazine-induced hepatitis. Cytochrome P450 1A2 has been identified as the target-autoantigen of anti-LM autoantibodies in both APECED-related AIH and dihydralazine-induced hepatitis. The latter may indicate that similar autoimmune pathogenetic mechanisms can lead to liver injury in susceptible individuals irrespective of the primary defect. Characterization of the autoantigen-autoantibody repertoire continues to be an attractive and important tool to get access to the correct diagnosis and to gain insight into the as yet unresolved mystery of how hepatic tolerance is given up and AIH ensues.