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Antiphospholipid Antibodies are Associated with Low Levels of Complement C3 and C4 in Patients with Systemic Lupus Erythematosus
Author(s) -
Garabet L.,
Gilboe I.M.,
Mowinckel M.C.,
Jacobsen A. F.,
Mollnes T. E.,
Sandset P. M.,
Jacobsen E.M.
Publication year - 2016
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/sji.12445
Subject(s) - medicine , complement system , antiphospholipid syndrome , antibody , connective tissue disease , systemic lupus erythematosus , immunology , gastroenterology , lupus erythematosus , vasculitis , autoimmune disease , disease
Complement activation and low complement levels are common in systemic lupus erythematosus ( SLE ). Antiphospholipid antibodies ( aPL ) are found in about 30‐40% of patients with SLE . This study aimed to investigate the association between aPL and complement levels in patients with SLE . Serum samples were collected from 269 patients with SLE enrolled in the Norwegian Systemic Connective Tissue and Vasculitis Registry ( NOSVAR ) during 2003‐2009, and from 353 controls. All samples were analysed for anti‐ β 2 glycoprotein 1 (anti‐ β 2 GP 1) and anticardiolipin antibodies ( aCL ), C‐reactive protein ( CRP ) and complement components C3 and C4. Median CRP level was significantly higher in cases than in controls (2.06 versus 0.90 mg/l; P < 0.0001). No significant difference in CRP was found between SLE patients with or without aPL (2.09 versus 1.89; P = 0.665). Median C3 levels were similar in cases (1.03 g/l) and controls (1.00 g/l), whereas median C4 levels were 0.16 g/l in cases versus. 0.19 in controls ( P < 0.0001). However, aPL ‐positive SLE patients had significantly lower median C3 levels (0.92 versus. 1.07 g/l; P = 0.001) and C4 levels (0.11 versus 0.16 g/l; P < 0.0001) compared to aPL ‐negative patients. Lower C3 and C4 values in aPL ‐positive SLE patients may reflect a higher consumption of C3 and C4 due to more pronounced complement activation in aPL ‐positive SLE patients compared to SLE patients without aPL .