RESUMEN

PURPOSE: Few studies have reported the roles of the complement system in concomitant idiopathic membranous nephropathy and IgA nephropathy (IMN-IgAN). Complement factor B (CFB) is a crucial factor that involved in the alternative complement pathway. We aimed to evaluate the association between disease activity (eGFR, anti-PLA2R antibody levels and 24 h urinary protein excretion), progression and serum CFB levels of IMN-IgAN patients. METHODS: In total, 39 IMN-IgAN patients (median follow-up, 46.6 months), 99 IMN patients and 92 IgAN patients participated in this study. The disease progression event was defined as end-stage renal disease (ESRD) or a 30% decline in estimated glomerular filtration rate (eGFR). The serum CFB concentration was measured by enzyme-linked immunosorbent assay. RESULTS: Serum CFB levels were lower in IMN-IgAN patients than in patients with IgAN only (P < .001). Serum CFB levels correlated positively with serum creatinine levels, anti-PLA2R antibody levels and 24 h urinary protein excretion (P < .05). Kaplan-Meier analysis revealed that IMN-IgAN patients with high serum CFB levels had a significantly lower cumulative renal survival rate than patients with low levels (log-rank test, P = .009). Multivariate Cox regression analysis showed that high baseline serum CFB levels were significantly associated with poor renal outcome in patients with IMN-IgAN (HR: 2.727, 95% CI 1.076-6.913, P = .034). CONCLUSION: High serum CFB levels correlated with increased serum creatinine, anti-PLA2R antibody and urinary protein excretion as well as poor renal prognosis in patients with IMN-IgAN, indicating that serum CFB may be a marker of disease activity and progression.

Asunto(s)

Glomerulonefritis por IGA , Glomerulonefritis Membranosa , Factor B del Complemento , Creatinina , Progresión de la Enfermedad , Femenino , Tasa de Filtración Glomerular , Glomerulonefritis por IGA/metabolismo , Humanos , Masculino , Pronóstico

RESUMEN

Objective:To detect serum level of complement factor B (CFB), and to explore its correlations with clinical parameters and prognosis in children with primary IgA nephropathy (IgAN).Methods:A total of 204 children with primary IgAN confirmed by kidney biopsy in the Department of Nephrology of the First Affiliated Hospital of Zhengzhou University from December 2014 to April 2017 were included in IgAN group.During the same period, 84 healthy children were included in healthy control group.Their mean age was (11.0±3.5) years and (10.9±3.2) years, respectively.Patients in IgAN group were divided into low CFB group (102 cases) and high CFB group (102 cases) according to the medium serum level of CFB measured by enzyme-linked immunosorbent assay. Spearman′ s coefficient was employed to analyze correlation amongst various parameters.Multivariable-adjusted Cox proportional ha-zards models were used to evaluate the relationship between serum CFB level and prognosis in children with IgAN. Results:Serum CFB levels were significantly higher in IgAN group than that in healthy control group [290.9 (186.2-453.9) mg/L vs.218.9 (155.0-321.3) mg/L, Z=-3.372, P=0.001]. Serum levels of CFB were negatively correlated with serum albumin ( r=-0.388, P<0.001) and estimated glomerular filtration rate ( r=-0.416, P<0.001), but positively correlated with serum creatinine ( r=0.305, P<0.001) and 24 h urinary protein ( r=0.456, P<0.001) in IgAN group.The incidences of crescents (C1-2) (70.6% vs.29.4%, χ2=34.588, P<0.001) and C 3 deposition (+ + -+ + + ) (63.7% vs.44.1%, χ2=7.892, P=0.005) were significantly higher in high CFB group than those in low CFB group. Kaplan- Meier analysis showed that high CFB levels predicted worse renal outcome in pediatric IgAN patients ( χ2=17.509, P<0.001). Multivariate Cox regression analysis showed that the high CFB level was the independent risk factor for the poor renal outcome ( HR=2.517, 95% CI: 1.284-4.932, P=0.007). Conclusions:High serum levels of CFB are associated with decreased renal function, increased urinary protein excretion, crescentic formation and poor renal outcome in pediatric IgAN patients.