FRI0259 SEROLOGICAL IMMUNE ABNORMALITIES ASSOCIATE WITH SPECIFIC PATHOLOGICAL ACTIVE LESIONS IN LUPUS NEPHRITIS

Background: Serological immune abnormalities such as anti-double strand DNA (dsDNA) antibodies (Abs) and hypocomplementemia (HC) are characteristic of lupus nephritis (LN). International Society of Nephrology/Renal Pathology Society (ISN/RPS) Classification of LN defines pathological active lesions (ALs) as including endocapillary hypercellularity, karyorrhexis, fibrinoid necrosis, cellular/fibrocellular crescents, and wire-loop lesion/hyaline thrombi [Reference 1]. Few reports have focused on the clinicopathological impact of serological immune abnormalities on pathological ALs. Objectives: To identify the clinicopathological association between serological immune abnormalities and pathological ALs in LN. Methods: We enrolled 126 Japanese LN patients who were subjected to renal biopsy in 11 hospitals from 2000 to 2018. We determined various clinical parameters at the time of renal biopsy, including creatinine (Cr), estimated glomerular filtration rate (eGFR), total protein (TP), IgG, IgA, IgM, C3, C4, CH50, anti-nuclear antibodies (Abs), anti-double strand DNA (dsDNA) Abs, anti-Sm Abs, anti-RNP Abs in the sera, urinalysis findings, presence of comorbidities (antiphospholipid antibody syndrome, hypertension, hyperlipidemia, diabetes mellitus, and hyperuricemia), and use of any immunosuppressive medications before renal biopsy. Renal biopsy findings were classified by ISN/RPS Classification including ALs. Immune deposits were evaluated by immunofluorescence. Elevation of serum anti- dsDNA Abs level [dsDNA Abs (+)] was defined as >12 IU/mL. HC was defined by C3 Results: Of 126 patients (104 females; mean age 41.8 years), dsDNA Abs (+) and HC (+) were found in 83 (65.9%) and 80 (63.5%), respectively. There were no significant differences in renal function, comorbidities, immune deposits or immunosuppressive medications before renal biopsy between dsDNA Abs (+) and dsDNA Abs (-), or between HC (+) and HC (-) patients. In pathological study, endocapillary hypercellularity, karyorrhexis, fibrinoid necrosis, cellular or fibrocellular crescents, and wire-loop lesion/hyaline thrombi were found in 81 (64.3%), 33 (26.2%), 19 (15.1%), 51 (40.5%), and 41 (32.5%), respectively. dsDNA Abs (+) had a higher frequency of endocapillary hypercellularity, karyorrhexis, fibrinoid necrosis, and wire-loop lesion/hyaline thrombi than dsDNA Abs (-). HC (+) had a higher frequency of endocapillary hypercellularity, karyorrhexis, fibrinoid necrosis, cellular or fibrocellular crescents, and wire-loop lesion/hyaline thrombi than HC (-). On multiple regression analysis dsDNA Abs and C3 associated with fibrinoid necrosis and karyorrhexis, respectively (β=0.25, p=0.049; β=-0.31 p=0.01). Conclusion: Serum anti-dsDNA Abs and HC were associated with fibrinoid necrosis and karyorrhexis, respectively. These results document that individual serological immune abnormalities associate with specific AL, suggesting that pathophysiological differences underlie each AL. References: [1] J Am Soc Nephrol. 2004;15:241-50. Disclosure of Interests: None declared