Safety and efficacy of influenza vaccination in systemic lupus erythematosus patients with quiescent disease.

OBJECTIVE

to assess the safety and efficacy of influenza vaccination in patients with systemic lupus erythematosus (SLE), and to evaluate the influence of immunosuppressive drugs on the immune response.

METHODS

SLE patients (n=56) and healthy controls (n=18) were studied. All patients had quiescent disease (SLE disease activity index<or=5). Four patient groups were defined on the basis of their drug use: (1) no drug treatment; (2) hydroxychloroquine treatment; (3) azathioprine treatment; (4) prednisone treatment. Participants received trivalent influenza subunit vaccine during October/November 2003. Disease activity scores and side effects were recorded. Antibody titres against influenza virus were measured before and 30 days after vaccination using the haemagglutination inhibition assay.

RESULTS

Influenza vaccination did not result in changes in disease activity and was well tolerated. SLE patients had fewer seroconversions or fourfold titre rises for A/H1N1 (p<0.001) and A/H3N2 (p<0.001) than healthy controls, while for B/Hong Kong the difference was of borderline significance (p=0.051). With regard to immunosuppressive treatment, fewer SLE patients using azathioprine developed fourfold titre rises against A/H3N2 (p=0.041), and fewer achieved titres of >or=40 against A/H3N2 (p=0.030) compared with the other patient groups.

CONCLUSIONS

Influenza vaccination in SLE patients with quiescent disease is safe but is less effective than in controls. Use of azathioprine was associated with a trend to decreased vaccination efficacy.