Expression Of Nephrin In Human IgA Nephropathy

ObjectiveThe present study was performed to detect the expression of nephrin in the glomerular in order to disclose the possible effect of nephrin in the development of proteinuria in patients with immunoglobulin A nephropathy (IgAN).MethodsA total of 37 renal samples diagnosed as IgA nephropathy was included in this study to summarize clinical manifestations and pathological features of IgAN. Clinica data including age, gender, urine routine, BUN, SCr, Alb, quantitate of urine protein were collected. According to the clinical manifestations, patients were divided into the group with with heavy proteinuria (the urinary protein exceeded 3.5g/24h, 13 cases) and the group with hematuria and/or light proteinuria(the urinary protein did not exceed 3.5g/24h, 24 cases). The expression of the nephrin in the glomerular staining by immunohistochemistry was semiquantitated by image-analysis system.Results1. Data of every patient was analyzed. ALB of the heavy proteinuria group was 22.25±6. 70g/L, while that of the hematuria was 43.45±3. 44g/L. BUN of the heavy proteinuria group was 8.82±4. 82mmol/L, while that of the hematuria was 4.89±0. 81mmol/L. SCr of the heavy proteinuria group was 102.51±65. 08umol/L, while that of the hematuria was 79.90±15. 93umol/L. Number of urine rad blood cell of the heavy proteinuria was 243.65±529. 86/HPF, while that of the hematuria was 269.89±721. 32/HPF. Quantitate of urine protein was 4.21±1. 04g/24h, while that of the hematuria was 0.74±0. 50g/24h.2. According to WHO pathological Grades, patients of the heavy proteinuria group distributed in grade II, III and IV, while patients of the hematuria group in grade I , II and III. Immunofluorescence results: In the group of heavy proteinuria 6 cases(46.1%) presented IgA+IgG+IgM deposition in the glomerular, and in the group of hematuria 9 cases (37.5%) presented IgA+IgM deposition in the glomerular. There was no significant difference between them(P>0.05).3. In control group, the distribution of nephrin showed a linear pattern along the glomerular basement membrane. In the heavy proteinuria group, the staining of nephrin on glomeruli was uneven, and weaker than controls. Crescents and sclerotic lesions were negative, and mesangial proliferation led to a scattered and sparse staining pattern. The distribution of nephrin in the hematuria group was similar to controls.4. In the patients with heavy proteinuria, the glomerular expression of nephrin decreased significantly compared with that in hematuria and control groups (P<0.05). There was no significant difference in the expression of nephrin between hematuria and control groups (P>0.05).Conclusion1. The pathological characteristicses of IgA nephropathy presenting with heavy proteinuria are not significantly different compared with the pathological characteristicses of IgA nephropathy with hematuria and/or light proteinuria.2. The dramatic decrease of nephrin expression might contribute to the development of proteinuria in the patients of IgA nephopathy with manifestation of heavy proteinuria, suggesting that nephrin may be the target of injury in IgAN and implying the role of nephrin in the pathogenesis of proteinuric diseases.