Immunofluorescence deposits in the mesangial area and glomerular capillary loops did not affect the prognosis of immunoglobulin a nephropathy except C1q:a single-center retrospective study

Abstract

Background: Immunoglobulin A nephropathy (IgAN) is identified as mesangial IgA deposition and is usually accompanied by other immunofluorescence deposits. The impact of immunofluorescent features in IgAN patients, however, remains unclear. Methods: Baseline clinicopathologic parameters and renal outcomes of 337 patients diagnosed with IgAN between January 2009 and December 2015 were analyzed. We then categorized these patients into four groups: without immunofluorescence deposits, mesangial-only, mesangial and glomerular capillary loops (GCLs), and GCLs-only. The study endpoint was end-stage kidney disease (ESKD) or a ≥ 50% decline in the estimated glomerular filtration rate (eGFR). Kaplan–Meier and Cox regression analyses were performed to calculate renal survival. Results: Of the 337 IgAN patients, women comprised 57.0%. Compared to patients with IgA deposition in the mesangial-only group, patients with IgA deposition in the mesangial +GCLs group were much heavier, and exhibited higher systolic blood pressure, lower serum IgG levels, and heavier proteinuria (all P < 0.05). Patients with IgG deposition in the mesangial +GCLs group presented with higher levels of cholesterol, heavier proteinuria than IgG deposition in the mesangial-only group (both P < 0.05). Compared with the mesangial-only group exhibiting C3 deposits, patients in the mesangial +GCLs group with C3 deposition had a higher systolic blood pressure (P = 0.028). A total of 38 patients (11.3%) continued to the study endpoint after a median follow-up time of 63.5 months (range,49.8–81.4). Kaplan–Meier analysis and Cox regression analysis showed that C1q deposition in the mesangial +GCLs group predicted a poor renal prognosis. Conclusions: IgA and IgG deposits in the mesangial region and GCLs were associated with more unfavorable clinical and histopathologic findings in IgAN patients. C1q deposition in the mesangial region and GCLs predicted a poor renal prognosis. However, the impact of the pattern of immunofluorescence deposits on renal outcomes remains to be proven by further investigation.