The Combined Clinical And Pathological Study Mesangial IgA Deposition Of Steroid Sensitive Nephrotic Syndrome

BackgroundIn the clinical practice, we notice that there is a group of patients who present with the typical nephrotic syndrome with the course of disease resembling the minimal change disease, but show a certain degree of IgA deposition on immunofluorescence. We define this group of patients as the MCD-IgA. So far, there are three different points of view yielded confusion in pathogenesis and possible different therapy and outcome. But few quantitive and comparative researches have been published.Objectives(1) To study the relationship of MCD-IgA with IgA nephropathy and the minimal change disease(MCD).(2) To find a certain feature which can divide MCD-IgA into subgroups to identify the different pathogenesis.(3) To elucidate whether the mesangial deposition of IgA is pathogenic and complement activation is involved in the mechanism as also.MethodsCase selection:the patients underwent renal biopsy in PUMCH between2001and2009, with intact clinical and pathological data. Group:MCD-IgA(n=35),IgA-NS(n=76),MCD(n=168).(1) Clinical manifestations and pathological features are compared among three groups retrospectively.(2) The H.S.Lee and Oxford classification are utilized to evaluate the severity of the renal biopsy of MCD-IgA and IgA-NS respectively, and the iPP6.0is used to analyze the proportion of the mesangial area compared to the total area of the glomerulus quantitively.(3)The MCD-IgA group is divided into two subgroups and analyze comparatively.(4) By immunohistochemical staining, the positive incidence of C4d deposition in the mesangial area is compared among three groups, as well as the distribution and the intensity semi-quantitively.Results(1) Compared to IgA-NS, the patients with MCD-IgA have lower serum albumin, more severe edema and hyperlipidemia, as well as the lower incidence of hypertension, hematuria and azotemia, which are similar to those in MCD. Urinary protein excretion in24hr is more than IgA-NS, but not statistically significant.(2)The histological comparison of the two groups shows that the patients with MCD-IgA have lower histological grading on light microscopy and slighter mesangial IgA staining on immunofluorecence. But refer to the frequency of the diffuse foot process effacement, MCD-lgA is significantly higher than IgA-NS.(3)According to the presence of the codeposition of the C3, we divide MCD-IgA into two subgroups. Though the clinical manifestations show no significant difference, the immunoflurecent intensity of IgA, the severity of the lesion on light microscopy and the proportion of the mesangial area are significantly different.(4)The positive incidence of C4d deposition in the mesangial area is significantly higher in the IgA-NS group compared to the MCD-IgA and MCD group. But refer to the subgroup division, though there are differences in the distribution and intensity of the staining, the positive incidence of C4d deposition is not sensitive enough.(5) Among the indices differentiating IgA-NS and MCD, the high sensitive one is the incidence of the hemauria (100.0%), while non-hyperlipidemia(97.4%), elevation of the creatine (95.0%) rank in the high specific ones.Conclusion(1) The clinical manifestations and pathological features of MCD-IgA show significant differences compared to the IgA-NS group,but are similar to those in MCD.(2) According to the presence of the codeposition of the C3, We divide the MCD-IgA group-into two subgroups. The positive group may suffer from the overlap syndrome, while the negetive group is more likely to have the asymptomatic deposition of IgA.(3)The positive incidence of the C4d deposition is significantly different between IgA-NS and MCD-IgA. But refer to the subgroup division, C4d is not sensitive enough.(4) Hematuria, non-hyperlipidemia and elevation of the creatine are helpful in distinguishing IgA-NS from MCD.