SAT0313 Different Serological Profiles and Activities in Two Onset Categories of Lupus Nephritis
Authors: M. Nakano, Y. Takahashi, H. Yamashita, H. Kaneko, A. Mimori
Journal: Annals of the Rheumatic Diseases (2016)

<h3>Background</h3> Previously, we reported a different renal prognosis between two onset categories of lupus nephritis (LN): LN that developed as a flare of systemic lupus erythematosus (SLE) after treating the prior non-renal SLE conditions successfully (delayed, D-LN) and LN manifesting at the time of SLE onset (early, E-LN).<sup>1)</sup> D-LN had a poorer renal prognosis than E-LN independent of the renal histology based on the chart review, but we had not analyzed the serological data in those LN patients. <h3>Objectives</h3> This study investigated possible differences in the serological profiles and activities between E-LN and D-LN. We focused on the serum levels of complement C3 and anti-ds DNA antibodies (Ab) as serological activities, and anti-Sm Ab as a serological profile. <h3>Methods</h3> Our hospital records for 1990–2015 were reviewed, and we identified 361 SLE patients diagnosed according to the American College of Rheumatology criteria for SLE. This study had two parts. 1. <i>Serological activity (C3 and anti-dsDNA Ab):</i> Of the 361 patients, 166 with LN (83 E-LN, 83 D-LN) had serum C3 and anti-dsDNA Ab levels measured on each admission to treat a total of 347 active SLE events (204 renal and 143 non-renal events). The serum data were compared between the E-LN and D-LN groups using the Mann–Whitney U-test and two-way analysis of variance (ANOVA). 2.<i>Prevalence of positive serum anti-Sm Ab:</i> From the 361 patients, we enrolled 129 patients diagnosed with SLE between Jan. 1996 and Oct. 2010 who were observed for more than 5 years. Patients diagnosed before 1996 were excluded because comprehensive anti-Sm Ab data were not available. Anti-Sm-Ab-positive patients were defined by at least once positive result before or at an LN manifestation. The frequency of anti-Sm-Ab-positive patients was compared among three patient-groups: E-LN, D-LN, and non-LN-SLE (the patients with no LN for more than 5 years). <h3>Results</h3> 1. The treated SLE conditions in the 83 E-LN patients included 91 renal events (35 flares) and 36 non-renal events, and those in the 83 D-LN patients comprised 113 renal events (52 flares) and 107 non-renal events. Serum anti-dsDNA Ab levels were higher in D-LN than in E-LN for the renal events (169 ± 139 IU/mL (EIA), n=98 <i>vs</i>. 120 ± 143 IU/mL, n=73, <i>p</i>&lt;0.01) and renal flare events (169 ± 130 IU/mL, n=47 <i>vs</i>. 48.8 ± 79.7 IU/mL, n=35, <i>p</i>&lt;0.01) (Fig). In both the D-LN and E-LN groups, the serum anti-dsDNA Ab levels were higher at renal events than non-renal events. The serum C3 levels were similar in the D-LN and E-LN groups during renal events. 2. The enrolled patients comprised 39 E-LN, 23 D-LN, and 67 non-LN-SLE. The frequency of anti-Sm-Ab-positive patients was higher in D-LN than non-LN-SLE (15/23, 65.2% <i>vs</i>. 16/67, 23.9%, <i>p</i>=0.001) and higher in D-LN than E-LN (15/23, 65.2% <i>vs</i>. 12/39, 30.8%, <i>p</i>=0.016). <h3>Conclusions</h3> High serum anti-dsDNA Ab titers were characteristic of LN that developed later in the course of an SLE flare (D-LN) compared with LN manifesting at the onset of SLE (E-LN). D-LN may reflect intractable SLE conditions. Positive serum anti-Sm antibodies were prevalent in D-LN patients in our study. Therefore, anti-Sm-Ab-positive SLE patients without LN may be at risk for the subsequent development of D-LN. <h3>References</h3> Takahashi Y, et al. Time of initial appearance of renal symptoms in the course of systemic lupus erythematosus as a prognostic factor for lupus nephritis. Mod Rheumatol 2009; 19: 293–301 <h3>Disclosure of Interest</h3> None declared