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Currently filtering by tag: IgA

IgA Dominant Infection-Associated Glomerulonephritis

A 65-year-old male presents to the ER with a new onset rash and blood in his urine. The ER doc is worried about an allergic reaction and on chem 7 finds that the patient’s creatinine is 6.5 mg/dl. The patient has been a diabetic for over 20 years and had been diagnosed with cellulitis of his left foot a week ago by a family practice physician who gave him antibiotics. A skin biopsy of the new onset rash during this hospitalization shows a leukocytoclastic vasculitis with IgA deposition. A kidney biopsy is requested. The kidney biopsy shows nodular diabetic glomerulosclerosis...

Potential Diagnostic Pitfall of PIF Method

The paraffin immunofluorescence technique is simple to perform for renal pathology laboratories familiar with routine IF. It is important as a salvage technique as well as to identify “masked” deposits. While the interpretation is similar to routine IF, there are important pitfalls to be aware of. Due to fixation, the glomerular capillaries will often contain residual serum on paraffin IF which is not typically present in routine IF sections from frozen tissue. This serum will stain nonspecifically positive for many of the antibodies employed. Photomicrograph A shows strong staining for IgA in the mesangium in a case of IgA  nephropathy....

Diagnose This! (January 8, 2018)

The immunofluorescence image shown is of IgA. What is the most likely diagnosis and clinical history?     ​   ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​ ​   ​ ​  ...

Crescentic Glomerulonephritis with IgA Deposits

This biopsy was taken from a 58-year-old male with no significant past medical history, who presents with gross hematuria, serum creatinine of 2.5 mg/dl and a urine protein/creatinine ratio of 1.4 g/g. The biopsy shows segmental rupture of the capillary loops associated with fibrinoid necrosis of the glomerular tuft and cellular crescent formation (Fig 1 – Jones stain). Of note, no mesangial or endocapillary proliferation is present. Immunofluorescence (Fig 2) shows mesangial granular staining for IgA (3+), C3 (1+), kappa (2+) and lambda (3+). Electron microscopy (not shown) shows scattered mesangial electron-dense deposits. The differential diagnosis in patients with necrotizing and...

IgA with Crescents, MEST-C

This biopsy is from a young adult patient with IgA nephropathy (the immunofluorescence image in Fig. 2 shows 2+ mesangial IgA deposits). While both glomeruli show endocapillary hypercellularity, the arrow indicates one glomerulus with a cellular crescent (Fig. 1). The recently updated Oxford classification of IgA nephropathy recommends that the frequency of crescents (cellular and/or fibrocellular) be added as the “C” in the MEST-Cscore (see reference). Although randomized clinical trials are still needed to determine optimal therapy, a C1 score (crescents in <25% of glomeruli) identifies patients at risk for poor renal outcome if not treated with immunosuppression, and a...

Diagnose This! (October 23, 2017)

This IF image is from a 22 y/o Asian male with hematuria. What immunoreactant does it represent and what is the diagnosis?     ​   ​ ​   ​   ​ ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​   ​  ...

IgAN and Acute Tubular Injury with Legionella

Acute kidney injury in the setting of Legionella pneumonia. This biopsy is a middle-aged person with Legionella pneumonia who developed acute kidney injury. Early in the hospitalization, the baseline creatinine was 1.0 mg/dl. However, the creatinine rose to 6.5 over 5 days and Nephrology was consulted. Urinalysis showed microscopic hematuria and 2+ proteinuria. The creatinine increased to 7.5 and a biopsy was done. Serologic studies were ordered and were pending at the time of biopsy. The images provided show a combination of acute tubular injury (Image 1), mild mesangial matrix expansion (Image 2) and mesangial IgA deposits (Image 3). While...

IgA Nephropathy

Figure 1 shows a renal biopsy from a 29-year-old man with no significant past medical history, who was found to have microscopic hematuria and non-nephrotic range proteinuria. The glomeruli show minimal mesangial matrix expansion and segmental hypercellularity. No crescents are identified. The surrounding tubules appear normal. Figure 2 shows dominant IgA mesangial deposits, consistent with IgA nephropathy. Remember that IgA deposits often persist and are seen in repeat biopsies even in patients who receive immunosuppressive therapy. Also, note the recent recommendation to include the presence or absence of crescents in the Oxford classification score (https://www.ncbi.nlm.nih.gov/pubmed/28341274).