IgA-dominant Glomerulonephritis Research Articles

Bacterial infection-related glomerulonephritis in patients with diabetes.

Diabetic patients are prone to infections, thus making them a unique cohort at risk of developing bacterial infection-related glomerulonephritis (IRGN). In total, 1693 adult diabetic patients underwent kidney biopsy between 2005 and 2021 at our tertiary care hospital in South India. Of these, 121 consecutive cases which met criteria of bacterial IRGN were included in this study. The mean age of the cohort was 53.1 ± 10.1 years and 83/121 (68.5%) were males. Majority (98.3%) had type 2 diabetes for a median duration of 6 (IQR, 2-12) years. The most common sites of infection were skin (47/121, 38.8%) and urinary tract (15/121, 12.4%). Fifty percent (58/121) of patients had underlying advanced diabetic kidney disease (DKD). Isolated C3 deposits (without immunoglobulin) occurred in 66/121 (54.5%) patients predominantly in advanced DKD patients. IgA-dominant glomerulonephritis occurred in only 9/121 (7.4%) patients. Short-course oral steroid was given to 86/121 (71.1%) patients. Steroid related dysglycemia and immunosuppression related infections occurred in 9/61 (14.8%) and 16/61 (26.2%) patients respectively. Of the 90 patients with follow up details >3 months, 46 (51.1%) progressed to kidney failure over a median period of 0.5 (IQR, 0-7.2) months. Patients diagnosed in the latter half of our study period (2013-2021) were older, less commonly presented with fever, had more pronounced hypocomplementemia and severe renal histology predominantly with a 'starry sky' immunofluorescence pattern. Superimposed bacterial IRGN on underlying DKD is associated with poor renal outcomes. Use of short course steroid was associated with significant toxicity.

IgA-dominant glomerulonephritis with DNAJB9-negative fibrillar polytypic immunoglobulin deposits in the subepithelium.

Fibrillary glomerulonephritis (FGN), a rare disease is pathologically characterized by glomerular fibril accumulation ranging from 12 to 24nm in diameter with negative Congo red staining. Recently, the identification of DnaJ homolog subfamily B member 9 (DNAJB9) as a highly sensitive and specific marker for FGN has revolutionized diagnosis of this disease. However, few recent studies have reported DNAJB9-negative glomerulonephritis with fibrillar deposits. As such, it remains unclear whether DNAJB9-negative cases can be considered equivalent to FGN. Here, we report the case of a 70-year-old woman who developed renal impairment and nephrotic-range proteinuria. Renal biopsy and pathological examination revealed focal glomerulonephritis with fibrocellular crescents. Immunofluorescence microscopy showed IgA-dominant deposition of polytypic IgG in the glomerulus. Electron microscopy revealed hump-like subepithelial electron dense deposits with fibrils of 15-25nm in diameter. These findings were consistent with FGN; thus, Congo red and direct fast scarlet (DFS) staining, and immunohistochemistry for DNAJB9 were performed. In addition to negative Congo red/DFS/DNAJB9 staining, laser microdissection (LMD) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) resulted negative for DNAJB9, which is a highly sensitive and specific marker for FGN. The patient's renal function further declined, prompting administration of rituximab weekly for 2weeks, similar to the treatment for FGN. This is a unique case of IgA-dominant glomerulonephritis with DNAJB9-negative fibrillar polytypic immunoglobulin deposits in the subepithelium, unlike previous DNAJB9-negative cases. Thus, DNAJB9-negative cases diagnosed based on accurate electron microscopic evaluation must be gathered, and LMD and LC-MS/MS must be used to analyze the organized fibrillar deposits to reveal the disease entity.

Double glomerulopathies or two-faced janus? A challenging case in the COVID-19 era.

SARS-CoV-2 very often causes kidney involvement through various mechanisms including: acute tubular injury, virus cell invasion, vascular damage due to hypercoagulability and finally dysregulation of the immune system. Even though there are no pathognomonic morphologic features that can rule out or confirm direct damage by SARS-CoV-2, the latest literature suggests that there may be some association. SARS-CoV-2 infection represents a poor prognostic factor, regardless of pulmonary involvement. We report a challenging case with complex renal biopsy findings suggestive of collapsing glomerulopathy and focal proliferative IgA-dominant glomerulonephritis in a patient affected by active hepatitis C virus (HCV), SARS-CoV-2 infection and personal history of cocaine abuse.

IgA immune complex deposits, what can lie behind them? Comments on a case of IgA dominant glomerulonephritis associated to staphylococcus infection

IgA immune complex deposits, what can lie behind them? Comments on a case of IgA dominant glomerulonephritis associated to staphylococcus infection

Henoch-Schönlein purpura-like presentation in IgA-dominant Staphylococcus infectionassociated glomerulonephritis – a diagnostic pitfall

In children and adults, Henoch-Schönlein purpura (HSP) has a characteristic clinical presentation that includes a purpuric lower extremity skin rash, IgA-dominant glomerulonephritis, and abdominal and joint pain. A similar clinical presentation can be seen in adults who have a systemic infection with methicillin-resistant Staphylococcus aureus. It is critically important to distinguish the IgAdominant glomerulonephritis of HSP from the IgA-dominant glomerulonephritis of staphylococcal infection, because HSP may need to be treated with corticosteroids and immunosuppressives, while Staphylococcus infection-associated glomerulonephritis requires antibiotics. We searched our renal biopsy database for cases of Staphylococcus infection-associated IgA-dominant glomerulonephritis, to identify those with an HSP-like presentation. Their clinical, laboratory, and biopsy findings are reviewed. Between 2004 and 2011, we identified 37 patients with culture-proven Staphylococcus infection-associated glomerulonephritis. Of these, 8 (22%) had an HSP-like presentation manifested by lower extremity purpuric skin rash. Mesangial IgA and C3 deposits were consistent findings on kidney biopsy. Crescents were uncommon. Four of the 8 patients received glucocorticoid (steroid) therapy for a presumed diagnosis of HSP. Renal function worsened in 3 patients, and 1 patient ultimately improved but developed sepsis during the course. Overall, renal outcome was poor in 71% of the cases despite mild chronic renal injury in the biopsy. In adult patients with an HSPlike presentation, a high index of suspicion for underlying Staphylococcal infection is warranted. Blood cultures are frequently negative. Cultures from the site of infection should be performed. Steroid treatment did not improve outcomes. Renal outcomes were frequently poor.

Discrimination between postinfectious IgA-dominant glomerulonephritis and idiopathic IgA nephropathy

Background: A unique form of postinfectious glomerulonephritis (PIGN) with IgA-dominant deposition mimicking IgA nephropathy has been increasingly reported. Methods: We compared the clinical and histological features of 12 patients with postinfectious IgA-dominant glomerulonephritis to 134 patients with idiopathic IgA nephropathy. Results: In addition to hypocomplementemia and subepithelial hump-shaped deposits characteristic of PIGN, patients with postinfectious IgA-dominant glomerulonephritis had older age (62.3 ± 16.9 vs. 37.9 ± 16.3 years; p < 0.001) and more frequently presented with acute renal failure (83.3% vs. 10.4%; p < 0.001) than patients with idiopathic IgA nephropathy. Moreover, glomerular changes including endocapillary proliferation, neutrophil infiltration, and capillary loops deposits by immunofluorescence were more commonly present in postinfectious IgA-dominant glomerulonephritis group (p < 0.001). Conclusions: PIGN could be characterized by glomerular IgA-dominant deposition resembling idiopathic IgA nephropathy. It is essential to differentiate postinfectious IgA-dominant glomerulonephritis from idiopathic IgA nephropathy because of the different treatments and prognosis of the two diseases.