Pos1495 low intensity of c1q deposition with renal immunofluorescence predicts long-term poor renal prognosis in lupus nephritis

Background Although the prognosis of lupus nephritis (LN) has been improved due to recent advances in diagnosis and treatment, its long-term renal outcome is still poor. In spite of previous studies that investigated a number of prognostic factors, association of long-term renal outcome with renal histological findings focusing on immunofluorescence has been little elucidated. Objectives To clarify renal histological and immunofluorescent findings associated with deterioration of renal function in LN. Methods Consecutive patients with biopsy-proven LN class III/IV/V from 2008 to 2017 in our hospital were included in the study. They were classified into two groups: patients with deterioration of renal function and those without. The deterioration of renal function was defined as more than 30% decline in estimated glomerular filtration rate (eGFR) from baseline. Clinical characteristics and renal histological findings with immunofluorescence at the time of LN diagnosis were compared between the two groups. Results Sixty-nine patients (class III/IV 34; class III/IV+V 21; class V 14) were included in the analysis. Renal function was deteriorated during 5 years observation in 12 patient (17.4%). There was no significant difference in age (48 vs 42 years, p=0.16), disease duration (11.4 vs 9.8 years, p=0.65), and urinary protein-to-creatinine ratio (2.3 vs 2.2 g/gCr, p=0.56) between the deterioration and non-deterioration groups. The treatment regimens including maximum prednisolone dose (41 vs 47 mg/day, p=0.14), cyclophosphamide use (42 vs 54%, p=0.53) and mycophenolate mofetil use (0 vs 24%, p=0.11) were also not different. Regarding renal histopathological findings, while proportion of III/IV class (83 vs 79%, p=1.00), activity index (1 vs 4, p=0.14), and chronicity index (4 vs 3, p=0.19) were not different between the two groups, intensity of C1q deposition in renal immunofluorescence was significantly weaker in the deterioration group than the non-deterioration group; proportion of C1q deposition in renal immunofluorescence ≤ 1+ was 100% in the deterioration group compared to 47% in the non-deterioration group (p=0.006). When we divided the patients according to the intensity of C1q deposition, the cumulative deterioration rates of renal function were significantly different (p=0.01, Figure 1). The patients with low intensity of C1q deposition (≤ 1) had a lower positivity of serum anti-dsDNA antibody (75 vs 96%, p=0.04) and a higher serum C3 levels (54 vs 40 mg/dl, p=0.03) at LN diagnosis. Anti-SSA antibodies tended to be higher in the deterioration group than the non-deterioration group (80 vs 64%, p=0.43). Figure 1. Conclusion Low C1q deposition in renal immunofluorescence at LN diagnosis is associated with poor renal prognosis in LN. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests None Declared.