title: Serum alpha-actinin antibody status in systemic lupus erythematosus and its potential in the diagnosis of lupus nephritis.
abstract: BACKGROUND
  In lupus nephritis (LN), deposition of pathogenic autoantibodies in the glomeruli is mediated via cross-reactivity with alpha-actinin. Association of serum alpha-actinin antibody (AαA) with LN has been shown in a few studies but the results are controversial.
  
  
  METHODS
  Eighty patients into entered the study. The diagnosis of SLE was confirmed according to the American College of Rheumatology criteria and LN was diagnosed by proteinuria ≥ 500 mg/24 hour and kidney biopsy. Serum AαA was measured with ELISA method. Receiver operating characteristics curve (ROC) analysis was applied to determine an optimal cutoff value for AαA to discriminate patients with and without LN at the highest sensitivity and specificity. The association of AαA with LN was determined by logistic regression analysis with calculation of odds ratio (OR).
  
  
  RESULTS
  Serum AαA was significantly lower in LN as compared with SLE patients without LN (P=0.001). Serum AαA at cutoff levels ≤ 59.5 pg/ml discriminated the two groups with sensitivity, specificity, positive predictive values of 60%. 90% and 85.7%, respectively. Serum AαA level ≤ 59.5 pg/ml was significantly associated with LN (OR=13.5, P=0.001) and the OR increased to 25.2 (P=0.003) after adjustment for age, sex, C3, C4, anti-ds-DNA, SLEDAI.
  
  
  CONCLUSIONS
  This study indicates that serum AαA decreases in LN and serum level ≤ 59.5 pg/ml is SLE and is predictive of nephritis.
authors.affiliation: Department of Rheumatology, Ayatollah Rouhani Hospital, Babol University of Medical Sciences, Babol, Iran.
authors.forename: Mansour
authors.initials: M
authors.lastname: Babaei
authors.affiliation: Rheumatic Disease Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Zahra
authors.initials: Z
authors.lastname: Rezaieyazdi
authors.affiliation: Rheumatic Disease Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Nayereh
authors.initials: N
authors.lastname: Saadati
authors.affiliation: Rheumatic Disease Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Massoud
authors.initials: M
authors.lastname: Saghafi
authors.affiliation: Rheumatic Disease Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Sahebari
authors.affiliation: Center for Health Sciences Research, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Bahram
authors.initials: B
authors.lastname: Naghibzadeh
authors.affiliation: Center for Health Sciences Research, School of Health, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Habibollah
authors.initials: H
authors.lastname: Esmaily
keywords: Anti-alpha-actinicn antibody; Diagnosis.; Nephritis; Systemic lupus erythematous