IgA anticardiolipin and IgA anti-ß2 glycoprotein I antibody positivity determined by fluorescence enzyme immunoassay in primary antiphospholipid syndrome.

BACKGROUND: Primary antiphospholipid syndrome (PAPS) is an autoimmune disease characterized by thrombosis and/or pregnancy morbidity as well as blood antiphospholipid (aPL) antibodies such as anticardiolipin (aCL), anti-ß2 glycoprotein I (anti-ß2GPI) antibodies of the IgG/IgM isotype and lupus anticoagulant (LA). The clinical significance of aCL and anti-ß2GPI antibodies of the IgA isotype in PAPS is still a controversial issue. METHODS: Sera and plasma were collected from 84 PAPS patients (54 with thrombosis and/or pregnancy morbidity and 30 with pregnancy morbidity alone), 66 seronegative patients (subjects with clinical manifestations of PAPS although with negative results on conventional antiphospholipid antibody testing), and 78 healthy blood donors. IgA aCL and IgA anti-ß2GPI were determined using fluorescence enzyme immunoassay (FEIA), (EliATM, Phadia AB, Uppsala, Sweden). For comparison purposes, the sera were also tested for IgG/IgM aCL/anti-ß2GPI antibodies using the same immunoassay method. LA was assayed following internationally accepted guidelines. RESULTS: Present respectively in 19% and 50% of the PAPS patients studied, IgA aCL and IgA anti-ß2GPI antibody frequencies were both statistically significant (p=0.001 and p<0.001, respectively). The mean titers of both IgA aCL and IgA anti-ß2GPI antibodies were higher in the thrombotic patients, but only the latter were significantly associated with thrombosis. Isolated IgA anti-ß2GPI antibody positivity was significantly prevalent (p=0.04) in seven (10.6%) of the seronegative patients. CONCLUSIONS: Positivity to IgA anti-ß2GPI antibody detected using FEIA was found to be clinically relevant in PAPS patients. Moreover the prevalence of isolated IgA anti-ß2GPI antibody positivity was significant in the seronegative patients.

The clinical relevance of early anti-adalimumab antibodies detection in rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis: A prospective multicentre study.

OBJECTIVES: To evaluate the relevance of anti-adalimumab (anti-ADA) antibodies (Abs) and their relationship with clinical/laboratory features in rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA). METHODS: Fifty-eight patients affected with RA, AS and PsA were prospectively enrolled. Clinical/laboratory characteristics, disease activity, anti-ADA, anti-nuclear (ANA), anti-double strand (ds)DNA, anti-extractable nuclear antigens (anti-ENA) and anti-phospholipid Abs (aPL) were evaluated at baseline, 4, 12 and 24 weeks of adalimumab treatment. RESULTS: Anti-ADA Abs were observed in 11/58 (19%) patients; they were detected within the 4th week of therapy in 90.9% of the positive subjects. Anti-ADA positivity was associated with significantly lower mean adalimumab serum levels (P<0.05). Treatment failure was observed in 20/58 (34.5%) patients and was significantly associated with anti-ADA Abs (P<0.05). Mean adalimumab serum levels were significantly lower in patients with treatment failure than in the responders one, both in the whole cohort (P<0.01) and in the group of anti-ADA positive patients (P<0.01). Adverse events happened more often in anti-ADA positive then in anti-ADA negative patients (27.3% vs 14.9%). CONCLUSIONS: Anti-ADA abs could be considered an early marker associated to a poor clinical response to adalimumab treatment. Routine ANA/anti-ENA/aPL monitoring did not reveal as useful tools to predict the development of anti-ADA abs.