The Effect Of Serum C3 Levels,mesangial C3 Deposition On Clinical And Pathological Characteristics In IgA Nephropathy

Objective:To identify the effect of serum C3 levels,mesangial C3 deposition on clinical and pathological characteristics of IgA nephropathy(IgAN)as well as investigate the influence of complement activated status in IgAN.Methods:We enrolled patients with primary IgAN diagnosed by renal biopsy at the Department of Nephrology,Second Hospital of Tianjin Medical University from August 2009 to April 2018,whose clinical pathological data were recorded.According to the inclusion and exclusion criteria,151 patients were included.According to the deposition of mesangial C3,the above 151 patients were divided into three groups: negative,weakly positive,and strong positive.According to the serum C3 levels,,the above 151 patients were divided into C3 reduction group(<85 mg/dl)and normal group.The patient’s basic information,clinical manifestations,biochemical indicators,Oxford pathological classification MEST-C score and other indicators were retrospectively analyzed.Results:(1)There were 67 males and 84 females(male:female ratio0.80:1),the average age was(37.69±11.67)years old,the median duration was 240 days,the average height was(168.19±8.48)cm,and the average body weight was(69.80±14.40)kg.,average systolic blood pressure was(129.63 ± 16.30)mmHg,average diastolic blood pressure was(84.74 ± 11.13)mmHg.(2)65 cases(43.05%)was classified in the negative C3 deposition group,51 cases(33.78%)was classified in the weakly C3 deposition group,35 cases(23.18%)was classified in the strongly C3 deposition group.33 cases(21.85%)was classified in the serum C3 decreased group while 118 cases was classified in the normal serum C3 group(78.15%).With the deposition of C3 in the mesangial area increased,the mean value of serum C3 decreased,the difference was statistically significant(P=0.000).(3)Clinical indicators: Compared with the normal serum C3 group,the blood urea nitrogen,serum creatinine and albumin were significantly higher than that in the serum C3 decreased group(P<0.05)(P= 0.006,0.035,0.009)while the fasting blood glucose,low-density lipoprotein,triglyceride,and 24-hour urine protein were significantly lower than that in the serum C3 decreased group(P<0.05)(P = 0.002,0.046,0.011,0.000).Compared with the negative mesangial C3 deposition group and the weakly mesangial C3 deposition group,the strongly mesangial C3 deposition group had significantly higher urea nitrogen,uric acid and serum creatinine while a significantly lower eGFR(P<0.05).(4)Pathological data: There is no difference between serum C3 decreased group and normal serum C3 group in the Oxford classification according to mesangial cell proliferation(M),endothelial proliferation(E),segmental glomerular sclerosis(S),tubular atrophy or interstitial fibrosis(T)and There was no significant difference in spherical sclerosis(S),tubular atrophy or interstitial fibrosis(T),and crescents(C)(P>0.05).But the mesangial C3 deposition was associated with T.Strong mesangial C3 deposition was associated with significantly severe tubular atrophy and interstitial fibrosis(p=0.001).Conclusions:1.The reduction of serum C3 and the strongly mesangial C3 deposition are related to the aggravation of clinical parameters of renal function;2.The Strongly mesangial C3 deposition is associated with severe tubular atrophy and interstitial fibrosis,accompanying the serious pathological damage;3.Both the reduction of serum C3 and the strongly mesangial C3 deposition are related to the activated state of the complement system,suggesting that the activation of the complement system participates in the pathogenesis and progression in IgA nephropathy.