Jun Ishizaki1, Kazuyoshi Saito2, Masao Nawata2, Yasushi Mizuno2, Mikiko Tokunaga2, Norifumi Sawamukai2, Masahito Tamura2, Shintaro Hirata2, Kunihiro Yamaoka2, Hitoshi Hasegawa2, Yoshiya Tanaka3. 1. First Department of Internal Medicine, Second Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health and Department of Hematology, Clinical Immunology and Infectious Diseases, Ehime University Graduate School of Medicine, Matsuyama, Japan. First Department of Internal Medicine, Second Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health and Department of Hematology, Clinical Immunology and Infectious Diseases, Ehime University Graduate School of Medicine, Matsuyama, Japan. 2. First Department of Internal Medicine, Second Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health and Department of Hematology, Clinical Immunology and Infectious Diseases, Ehime University Graduate School of Medicine, Matsuyama, Japan. 3. First Department of Internal Medicine, Second Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health and Department of Hematology, Clinical Immunology and Infectious Diseases, Ehime University Graduate School of Medicine, Matsuyama, Japan. tanaka@med.uoeh-u.ac.jp.
Abstract
OBJECTIVE: The aim of this study was to clarify the clinical characteristics and predictors of silent LN (SLN), a type of LN in SLE without abnormal urinalysis or renal impairment. METHODS: Of 182 patients who underwent renal biopsy, 48 did not present with abnormal urinalysis or renal impairment at the time of biopsy. The patients with LN (SLN group, n = 36) and those without LN (non-LN group, n = 12) were compared with respect to their baseline characteristics. Bivariate analysis comprised Fisher's exact test and the Mann-Whitney test, whereas multivariate analysis employed binomial logistic regression analysis. RESULTS: LN was histopathologically identified in 36 of 48 patients. According to the International Society of Nephrology/Renal Pathology Society classification, 72% of the SLN patients were classified as having class I/II, with a further 17% having class III/IV. Bivariate analyses indicated that platelet count, serum albumin, complement components (C3 and C4), complement haemolytic activity (CH50), anti-Sm antibody titre and anti-ribonucleoprotein antibody titre were significantly different between groups. Multivariate analysis indicated that CH50 and C3 titres were significantly lower in the SLN group, whereas anti-Sm antibody titre was significantly higher. The cut-off titre, calculated based on the receiver operating characteristic curve for CH50, was 33 U/ml, with a sensitivity and specificity of 89% and 83%, respectively. The cut-off titre for anti-Sm antibodies was 9 U/ml, with a sensitivity and specificity of 74% and 83%, respectively. CONCLUSION: Low titres of CH50 and C3 and a high titre of anti-Sm antibody were identified as predictors of SLN.
OBJECTIVE: The aim of this study was to clarify the clinical characteristics and predictors of silent LN (SLN), a type of LN in SLE without abnormal urinalysis or renal impairment. METHODS: Of 182 patients who underwent renal biopsy, 48 did not present with abnormal urinalysis or renal impairment at the time of biopsy. The patients with LN (SLN group, n = 36) and those without LN (non-LN group, n = 12) were compared with respect to their baseline characteristics. Bivariate analysis comprised Fisher's exact test and the Mann-Whitney test, whereas multivariate analysis employed binomial logistic regression analysis. RESULTS: LN was histopathologically identified in 36 of 48 patients. According to the International Society of Nephrology/Renal Pathology Society classification, 72% of the SLN patients were classified as having class I/II, with a further 17% having class III/IV. Bivariate analyses indicated that platelet count, serum albumin, complement components (C3 and C4), complement haemolytic activity (CH50), anti-Sm antibody titre and anti-ribonucleoprotein antibody titre were significantly different between groups. Multivariate analysis indicated that CH50 and C3 titres were significantly lower in the SLN group, whereas anti-Sm antibody titre was significantly higher. The cut-off titre, calculated based on the receiver operating characteristic curve for CH50, was 33 U/ml, with a sensitivity and specificity of 89% and 83%, respectively. The cut-off titre for anti-Sm antibodies was 9 U/ml, with a sensitivity and specificity of 74% and 83%, respectively. CONCLUSION: Low titres of CH50 and C3 and a high titre of anti-Sm antibody were identified as predictors of SLN.
Authors: Mariangelí Arroyo-Ávila; Yesenia Santiago-Casas; Gerald McGwin; Ryan S Cantor; Michelle Petri; Rosalind Ramsey-Goldman; John D Reveille; Robert P Kimberly; Graciela S Alarcón; Luis M Vilá; Elizabeth E Brown Journal: Clin Rheumatol Date: 2015-04-22 Impact factor: 2.980