IgA deficiency and membranous glomerulonephritis

Selective IgA deficiency associated with glomerulonephritis is rare and no previous reports in childhood have been made of the association of IgA deficiency and membranous glomerulonephritis (MGN). We report a 5-year-old boy with selective IgA deficiency and MGN. He presented with nephrotic syndrome. Percutaneous renal needle biopsy showed diffuse global thickening on light microscopy and heavy IgG and moderate C3 deposits were found on immunofluorescence. Electron microscopy detected extensive global subepithelial deposition of electron-dense material with frequent intramembranous extension and spike formation. The pathological diagnosis was diffuse MGN stage 1. Oral prednisolone (1 mg kg(-1) day(-1)), angiotensin-converting enzyme inhibitors (ACEI), and angiotensin II receptor blocker (ARB) were given resulting in reduction of proteinuria. The prednisolone dose was gradually tapered and discontinued after 2 months. At present the patient has been in complete remission for 10 months despite the discontinuance of prednisolone. In conclusion, our treatment with corticosteroid, ACEI and ARB reduced proteinuria and was effective for our case with selective IgA deficiency and MGN.

Secondary membranous glomerulonephritis (MGN) is usually caused by drugs or systemic disorders that produce circulating immune complexes. However, some disorders that did not seem to form circulating immune complexes have been listed as underlying diseases of secondary MGN. The case of a 13-year-old boy with MGN and unilateral renal agenesis is presented. Renal histology showed segmental MGN with mesangial proliferation and mesangial electron-dense deposits, and no other underlying disorder except for unilateral renal agenesis. Patients with MGN, who have histological findings suggesting secondary MGN and no underlying disorder distinctly causing formation of circulating immune complexes, should not be defined as having idiopathic or secondary forms, but as having a ‘cryptogenic’ form.