IgA nephropathy with minimal change disease.
OBJECTIVE
Patients with IgA nephropathy typically present with hematuria and subnephrotic proteinuria. Nephrotic syndrome is uncommon in IgA nephropathy, and when present, it is usually associated with severe histologic features, such as endocapillary proliferation, segmental sclerosis, and crescent formation. Rarely, patients with IgA nephropathy present with nephrotic syndrome and only mild mesangial disease. This study sought to better characterize these patients.


METHODS
A retrospective review of cases of IgA nephropathy diagnosed from 2004 to 2011 identified patients with nephrotic range proteinuria and histologically mild IgA nephropathy. Specifically, using the Oxford Classification of IgA Nephropathy, we identified cases that lacked endocapillary proliferation or segmental sclerosis.


RESULTS
The cohort consisted of 17 patients, including 10 men and 15 adults. The median serum creatinine was 0.9 mg/dl (range=0.7-3.1), median 24-hour urine protein was 8.0 g/d (3.0-18.0 g), and 14 patients were fully nephrotic, whereas the remaining 3 patients fulfilled two of three criteria for nephrotic syndrome. Biopsies revealed IgA-dominant or codominant deposits accompanied by mesangial proliferation in 14 patients (82.4%). Electron microscopy showed mesangial deposits and extensive foot process effacement (median=90%). Initial treatment consisted of corticosteroids, although many patients required additional agents to maintain remission status. Over a median follow-up of 20 months (2.2-82 months), 14 patients experienced a complete response, and 3 patients showed a partial response, with a median response time of 2 months (0.5-27 months). At least one relapse of nephrotic syndrome occurred in nine patients (53%). All patients exhibited stable or improved renal function over the follow-up period.


CONCLUSIONS
The findings in this cohort and previous studies suggest that rare cases of mild IgA nephropathy with nephrotic range proteinuria exhibit a clinical presentation, biopsy findings, treatment response, and outcome more typical of IgA nephropathy with superimposed minimal change disease. This study favors the view that such cases represent a dual glomerulopathy.
Department of Pathology and Cell Biology, Division of Renal Pathology, and LB684@columbia.edu.
Leal C
LC
Herlitz
Department of Medicine, Division of Nephrology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, New York.
Andrew S
AS
Bomback
Department of Pathology and Cell Biology, Division of Renal Pathology, and.
Michael B
MB
Stokes
Department of Medicine, Division of Nephrology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, New York.
Jai
J
Radhakrishnan
Department of Pathology and Cell Biology, Division of Renal Pathology, and.
Vivette D
VD
D'Agati
Department of Pathology and Cell Biology, Division of Renal Pathology, and.
Glen S
GS
Markowitz
D000305:Adrenal Cortex Hormones / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D005922:Glomerulonephritis, IGA / Q000097:blood / Q000150:complications* / Q000188:drug therapy / Q000473:pathology*; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009402:Nephrosis, Lipoid / Q000097:blood / Q000150:complications* / Q000188:drug therapy / Q000473:pathology*; D011507:Proteinuria / Q000209:etiology; D012008:Recurrence; D012189:Retrospective Studies; D012709:Serum Albumin / Q000378:metabolism; D016896:Treatment Outcome; D055815:Young Adult
D000305:Adrenal Cortex Hormones; D007166:Immunosuppressive Agents; D012709:Serum Albumin; D003404:Creatinine
IgA; nephrotic syndrome; renal biopsy; renal pathology