The Clinicopathological Significance Of IgA Nephropathy With The C4d Staining On The Glomerular Capillary Loops

[Objective]1. To study the clinicopathological correlations about 2009 Oxford classification of IgA nephropathy (IgAN).2. To study the clinicopathological significance of IgAN with the complement C4d expression on the glomerular capillary loop from the different pathway of complement activation. And discussing this part of IgAN about the clinicopathological correlations and prognosis.[Methods]1. This retrospective study included 377 of patients who underwent a renal biopsy diagnosis at our department among three years from the thousands of IgAN patients. Counted the pathological features according to the PAM staining slice and then collected the clinical data of the 377 IgAN patients.2. C4d and C1q were performed by Elivison Immunohistochemistry in all 377 case. Collected other immune staining slice and then grouped observations. The 2009 Oxford classification of IgAN was refered to the pathological features.3. Recorded the information of all 377 case among pathological features、immune deposits、clinical features and the prognosis.[Results]1. In accordance with 2009 IgAN Oxford classification, there were 374 with mesangial proliferative,246 with segmental sclerosis,101 with endocapillary hypercellularity, and 126 with tubular atrophy/interstitial fibrosis in all 377 IgAN patients after observing by light microscopy. 2. The mesangial proliferative and endocapillary hypercellularity had no correlation with MAP, proteinuria (g/day) and SCr (P>0.1); segmental sclerosis was in interrelated to the proteinuria (g/day) and SCr (P<0.05); tubular atrophy/interstitial fibrosis was in interrelated to the MAP, proteinuria (g/day) and SCr (P<0.01); arterial lesions was related to the MAP, proteinuria (g/day) and SCr (P<0.01).3. There were 262 IgAN with C4d positive (69.5%) and 61 with C1q positive(16.2%) in the all 377 IgAN. The C4d expression in IgAN glomerular can be divided into three types:C4d negative (115 cases), with mesangial deposition (113 cases), and with mesangial and capillary loops deposition (149 cases).4. The positive rate of IgM and Clq were different among the three types of C4d deposition, the difference had statistically significant (P<0.05). And the positive rate of C1q was closely related to the capillary loops deposition of C4d (P<0.01).5. The pathological lesions such as glomerular segmental sclerosis and tubular atrophy/interstitial fibrosis were different between the group of IgAN with C4d capillary loops deposition and the group of the other two types of C4d staining, the difference had statistically significant (P<0.01); The clinical features of MAP, macroscopic hematuria, proteinuria (g/day), SCr and BUN also had differences between the two groups, the difference had statistically significant (P<0.05).6. In the group of IgAN with C4d capillary loops deposition, there were a part of IgAN with Clq positive. And this part of IgAN had more serious pathological lesions and more poorer clinical course.7. The group of IgAN with C4d capillary loops deposition showed a worse prognosis within 2 years compared to the other two types of C4d staining (P<0.05).[Conclusion]1. The pathological features as segmental sclerosis, tubular atrophy/interstitial fibrosis and arteriosclerosis of IgAN Oxford classification indicated a worse clinical course for closed relating to the pathological features.2. Compared to the group of C4d negative and C4d mesangial deposition, IgAN with C4d deposition on glomerular capillary loops had more serious pathological lesions and poorer clinical course and worse prognosis within 2 years.3. In the group of IgAN with C4d capillary loops staining, there may be a part of IgAN with the activation of classical pathway of complement which the pathological features, clinical features and prognosis were different from the other types of IgAN, and should be considered as a new subtype of IgAN.4. The IgAN with C4d staining on the glomerular capillary loops could help to identify patients with a poor short-term prognostic and showed as an important prognostic indicator.