Antineutrophil cytoplasmic antibody negative pauci-immune extracapillary glomerulonephritis

Comparison of Clinico-pathologic features and outcomes of ANCA negative and ANCA positive pauci immune crescentic glomerulonephritis: A single centre study

Introduction

Pauci-immune crescentic glomerulonephritis (PICN) is an important cause of rapidly progressive renal failure. 10-40% of PICN cases have ANCA (antineutrophil cytoplasmic antibody) negative serology. The present study compared clinico-pathologic features, Brix's renal risk score, Berden's histopathological classes and differences in outcome between ANCAnegative vs ANCA positive PICN patients.

Materials and Methods

Sixty-one patients of biopsy-proven PICN were studied. Biochemical findings and ANCA serology were recorded. Renal biopsy slides were reviewed along with direct immunofluorescence. Clinical and histological features were compared between ANCA negative and positive PICN using the Man Whitney U test and Chi-square test. Patients were compared for distribution in Berden's histological classes and Brix's renal risk categories. Patient and renal survival were compared using Kaplan-Meier survival analysis.

Results

ANCA negative PICN patients were younger (44.9 ± 16.5 years vs 53.6 ± 15.1 years, P = 0.049). Nasal (0 vs 18%, P = 0.035) and pulmonary involvement (9% vs 38%, P = 0.014) were lower in ANCA negative group. Both ANCA groups had similar renal biochemical profiles, percentage normal glomeruli, 16.3 ± 18.2 vs 21.7 ± 20.4 and percentage glomeruli with crescents, 64.5 ± 28.1 vs 64.3 ± 27.1. Twenty-seven per cent of ANCA negative cases fell in the sclerotic class in Berden's classification vs just 2.5% in ANCA positive group (p = 0.037) without significant difference in Brix's renal risk categories (p = 0.329). Thirteen per cent of ANCA negative patients achieved complete remission on treatment compared to 33% in ANCA positive patients. Patient survival and overall probability of progressing to ESRD were similar in the two groups.

Conclusion

ANCA negative PICN cases present at younger ages. Nasal and pulmonary involvement is uncommon in these patients. Patient survival and progression to ESRD are similar in both ANCA groups.

A Meta-Analysis and Cohort Study of Histopathologic and Clinical Outcomes in ANCA-Negative versus -Positive Vasculitis

BACKGROUND

ANCA-negative pauci-immune glomerulonephritis (PIGN) represents a rare and often under-studied subgroup of the vasculitides. This study aims to investigate differences in the clinical phenotype, renal histological features, and clinical outcomes of patients with PIGN, with and without serum ANCA positivity.

METHODS

A cohort of biopsy-proven PIGN with and without detectable circulating ANCA was constructed from a single center between 2006 and 2016. Primary outcomes compared clinical presentation and histopathological features according to ANCA status, with multivariate Cox regression to compare mortality and ESKD. A systematic review and meta-analysis of the published literature was undertaken.

RESULTS

In our cohort of 146 patients, 22% (n=32) had ANCA-negative disease, with a comparatively younger mean age at diagnosis; 51.4 versus 65.6 years (P<0.001). In total, 14 studies, inclusive of our cohort, were eligible for meta-analysis, totaling 301 patients who were ANCA negative. Those with ANCA-negative disease tended to have fewer extrarenal symptoms and a higher frequency of renal-limited disease, but both failed to reach statistical significance (P=0.92 and P=0.07). The risk of ESKD was significantly higher in seronegative disease (RR, 2.28; 95% confidence interval, 1.42 to 3.65; P<0.001), reflecting our experience, with a fivefold increased risk of ESKD in ANCA-negative disease (P<0.001). No significant difference in the chronicity of histopathological findings was seen and the meta-analysis showed no difference in morality (RR, 1.22; 95% confidence interval, 0.63 to 2.38; P=0.55).

CONCLUSION

Our findings demonstrate that ANCA-negative PIGN presents in younger patients, with fewer extrarenal manifestations and higher ESKD risk, despite a lack of difference in histopathology. This study provides the impetus for further research into the pathogenesis, treatment response, and duration of immunotherapy in ANCA-negative disease. We suggest that the absence of positive ANCA serology should not discourage treatment and for clinical trials to include patients who are ANCA negative.

A Case of Colon Cancer and Pauci-Immune Crescentic Glomerulonephritis

The association between membranous nephropathy and cancer has been well documented. Crescentic glomerulonephritis (GN) has also been associated with various types of cancers. To our knowledge, there has only been one previously documented case of seronegative pauci-immune crescentic glomerulonephritis associated with colon cancer. We present a case of a 51-year-old male with newly diagnosed high-grade poorly-differentiated colon carcinoma who was found to have seronegative pauci-immune crescentic GN with 70% involvement of glomeruli on renal biopsy. The patient was treated with pulse steroids and rituximab with resolution of acute kidney injury.

Something Out of Nothing: A Rare Case of Pulmonary Renal Syndrome With Pauci-Immune Glomerulonephritis and Diffuse Alveolar Hemorrhage With Negative Serologies

Background: Pauci-immune crescentic glomerulonephritis (CrGN) is one of the most common etiologies of rapidly progressive glomerulonephritis. This condition presents with crescentic glomerulonephritis with little or no immunoglobulin staining and negative serological workup aside from a positive antineutrophil cytoplasmic autoantibody (ANCA). Typically, patients with pauci-immune CrGN have an underlying systemic small vessel vasculitis, but in rare cases, it presents without any known vasculitis or ANCA. Pauci-immune ANCA negative CrGN is often strictly isolated to the kidneys. In this case, we present a patient with ANCA negative, pauci-immune CrGN with severe diffuse alveolar hemorrhage.

Case Presentation: A 66-year-old Hispanic woman with a past medical history of controlled hypertension presented with fatigue and dysphagia. On admission, her vital signs were significant for hypoxia on room air, and her physical exam was remarkable for crackles bilaterally. The initial laboratory results revealed anemia (hemoglobin 5.2 g/dL), hyperkalemia (6.3 mmol/L), elevated creatinine (4.50 mg/dL, with a baseline of 0.9mg/dL). Urinalysis showed moderate blood and urine protein (200 mg/dL). Urine microscopic examination showed 25-50 RBCs seen/high power field.

The patient was admitted to ICU due to hypoxia, a computed tomography scan of the chest/abdomen/pelvis was obtained and revealed multifocal pulmonary consolidations. A blood transfusion was ordered. The patient began to have hemoptysis and subsequent bronchoscopy showed diffuse alveolar hemorrhage. ICU team proceeded to intubate her as the hemorrhage continued to worsen. Further workup revealed a positive anti-nuclear antibodies (ANA) of 1:40, but otherwise negative serologies including myeloperoxidase (MPO)-ANCA, glomerular basement membrane antibody, and anti-double stranded DNA. Kidney biopsy showed necrotizing glomerulonephritis with crescents and negative immunofluorescence. She was diagnosed with pauci-immune ANCA-negative vasculitis with associated diffuse alveolar hemorrhage and nephritis based on these results and was started on pulse-dose steroids. The patient was started on intravenous (IV) high-dose cyclophosphamide, which helped improved the overall clinical condition significantly. After creatinine began trending down and urine output improved, the patient was discharged on a regimen of daily oral cyclophosphamide and steroid taper. Patient oxygen requirements decreased and she was sent home with supplemental oxygen while requiring 3L/min of oxygen.

Conclusion: Pauci-immune and ANCA-negative glomerulonephritis with concurrent diffuse alveolar hemorrhage is exceptionally rare. In this situation, medical management relied on clinical evidence from similar populations in the use of steroids and cyclophosphamide. This case report aims to shed more light on the clinical progression and management of this condition. Here we present a case of pulmonary-renal syndrome with biopsy-proven glomerulonephritis but without ANCA positive serologies.

When Anti-Neutrophil Cytoplasmic Antibody Fails: A Case of Anti-Neutrophil Cytoplasmic Antibody Negative Granulomatosis With Polyangiitis

Granulomatosis with polyangiitis (GPA) is a vasculitis of small and medium-sized vessels and presents with varying signs and symptoms. It includes upper and lower airway manifestations and glomerulonephritis with a positive antineutrophil cytoplasmic antibody (ANCA) in serology in 90% of cases. However, about 10% of cases with GPA can have negative serology, often resulting in a diagnostic delay. Obtaining a tissue pathology is needed to confirm GPA. Here we present a 77-year-old male who presented with generalized weakness and loss of appetite and was found to have glomerulonephritis and bilateral opacities in the lungs with a negative ANCA. He was diagnosed with ANCA negative granulomatosis with polyangiitis after a renal biopsy revealed necrotizing inflammation with crescent formation. He was successfully treated with systemic glucocorticoids and rituximab. In conclusion, prompt diagnosis and treatment of ANCA negative vasculitis are required to decrease mortality.

Significance of Crescentic Glomeruli in Acute Kidney Injury with Rheumatoid Arthritis

Crescentic glomerulonephritis (GN) without immune reactants or deposits (referred to as pauci-immune) is typically characterized by the presence of anti-neutrophilic cytoplasmic antibodies (ANCA). While ANCA-negative patients might be expected to have a more benign course, they often have poor renal outcomes, especially without treatment with steroids and immune-modulating therapy. Pauci-immune crescentic GN can also co-exist with other autoimmune conditions, including rheumatoid arthritis (RA). Here, we describe an ANCA-negative patient with RA who developed dialysis-requiring acute kidney injury (AKI) with findings consistent with focal pauci-immune crescentic GN (i.e., no IgG or immune complex on kidney biopsy). Coexistent conditions included Klebsiella sepsis attributed to pneumonia, rhabdomyolysis, leukocytoclastic immune-mediated skin vasculitis, and positive ANA. He had spontaneous improvement in renal function without immunosuppressive therapy. This crescentic GN was not associated with poor renal outcome as AKI resolved with supportive care and treatment of his infection. The AKI was likely multifactorial with co-existing acute tubular necrosis in the setting of Kebsiella sepsis and rhabdomyolysis, and the crescentic GN was felt more likely to be related to the infection rather than having a primary role. This case highlights the importance of viewing crescentic GN in the context of the clinical picture, as it may not always lead to the need of aggressive immune suppression and is not a universally poor prognostic kidney finding. However, these cases do warrant close follow-up as our patient had recurrent RA disease manifestations over the next 2 years that eventually led to his death from severe pulmonary hypertension.