Antibodies to selected minor target anti-neutrophil cytoplasmic antigens in systemic lupus patients

Abstract EN

Background: Anti-neutrophil cytoplasmic antibodies (ANCA)minor subsets (elastase , lysozyme , cathepsin G , lactoferrin & BPI )are detected among systemic lupus erythromatus patients causing vasculitis.

Systemic lupus erythematosus (SLE) is the prototypic immune complex disease, characterized by excessive autoantibody production, immune complex formation and immunologically mediated tissue injury.

Methods& Patients: A cross-sectional study was conducted on two main groups ,74 patients with SLE and 30 apperantly healthy control volunteers referred to immunology department in teaching laboratories \ medical city during period of (1st of march – 31st of May) 2011.

Antinuclear antibody (ANA) ,Cathepsin G, elastase, lactoferrin, lysozyme, bactericidal permeability increasing protein and C1q were detected by enzyme-linked immunosorbent assay (ELISA) technique.

While dsDNA was detected by indirect immunofluorescent(IIF) technique and C3,C4 by single radial immunodiffusion (SRID ) .

Result: Among patients group the mean levels of Cathepsin G (9.19 IU/ml), Elastase( 8.46 IU/ml) , Lysozyme (6.81 IU/ml), Lactoferrin (9.2 IU/ml)and BPI (5.59 IU/ml).

Among positive ANA result cathepsin G was detected in high percent (35.1%).

In regard to dsDNA positive result elastase Ab was detected in 18 (46.3%) with significant P value 0.00,while Cathepsin G (47.4%) & lactoferrin Ab(31.6%)were significantly found among C1q positive patients .Interestingly lactoferrin Ab associated with low complement C3&C4 levels .

Conclusion: Anti-neutrophil cytoplasmic antibody has a role among SLE patients in which cathepsin G detected in 35.1% among ANA positive patients ,while elastase & cathepsin G,significantly associated with disease activity (positive dsDNA,C1q) ,on other hand lactoferrin had a significant results in association with renal involvement (low C3,C4 levels ).