Anticardiolipin antibodies in rheumatoid patients treated with etanercept or conventional combination therapy: direct and indirect evidence for a possible association with infections

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Anticardiolipin antibodies in rheumatoid patients treated with etanercept or

conventional combination therapy: direct and indirect evidence for a

possible association with infections

G Ferraccioli, F Mecchia, E Di Poi and M Fabris

Chair and Division of Rheumatology, DPMSC, Udine University Medical Centre,

University of Udine, 33100 Udine, Italy

Correspondence to:

Professor G Ferraccioli, Chair and Division of Rheumatology, DPMSC, Udine

University Medical Centre, University of Udine, 33100 Udine, Italy;

gf.ferraccioli@...

ABSTRACT

Objective: To assess the occurrence of anticardiolipin antibodies (ACA) (as

well as of anti-DNA antibodies) in patients with rheumatoid arthritis

treated with etanercept or combination therapy.

Methods: Eight patients treated with etanercept 25 mg twice weekly were

studied for a period of 85 weeks. A control group of 39 patients with

rheumatoid arthritis undergoing combination treatment (methotrexate (MTX) +

cyclosporin A or MTX + chloroquine) were studied for the same period of

time. The occurrence of anticardiolipin antibodies (ACA-IgG) and anti-DNA

was examined, together with the possible occurrence of infections due to

bacteria capable of inducing B cell activation.

Results: In 5/8 patients receiving etanercept an increase of ACA-IgG was

seen, while anti-DNA became positive in 3/8 patients. A nasal or bronchial

infection due to Staphylococcus aureus (Staph aureus) or a urinary tract

infection due to E coli, occurred in all five cases. Antibiotic treatment

produced a return to normal of ACA-IgG, and also of anti-DNA, in all cases

except one. The infectious agent was eradicated in all subjects but one. In

the control group Staph aureus was found in the nasal swab in 10/39

subjects; ACA-IgM (followed by ACA-IgG) appeared at the same time as

infection occurred in 6/10, while no infection related to the increased

ACA-IgM was recorded in the other four.

Conclusions: Bacterial DNA, especially that enriched in CpG motifs, is a

powerful immunostimulant that may, in some cases, lead to ACA or anti-DNA

positivity, once tumour necrosis factor is blocked. Eradication of the

infections leads to a rapid decrease of ACA-IgG and of anti-DNA levels.