Suspending methotrexate could boost influenza vaccine immunogenicity
medwireNews: Patients with rheumatoid arthritis (RA) can improve their immune response to influenza vaccination by temporarily discontinuing methotrexate treatment, results of a randomized trial suggest.
Treatment with methotrexate “significantly decreases the satisfactory response of patients with RA to pneumococcal and seasonal influenza vaccination,” explain researcher Eun Bong Lee (Seoul National University College of Medicine, South Korea) and colleagues.
“Therefore, a novel strategy to improve the vaccine response of such patients with RA is needed,” they add.
The team found that 51.0% of 49 patients whose methotrexate treatment was suspended for 2 weeks before and 2 weeks after seasonal influenza vaccination achieved a satisfactory antibody response – defined as at least a fourfold increase in titers at 4 weeks postvaccination – against all three antigens in the vaccine, compared with 31.5% of 54 patients who continued to receive methotrexate throughout the study.
Conversely, the rate of satisfactory response to all three antigens was significantly lower among the 44 participants whose treatment was suspended for 4 weeks before vaccination compared with patients who continued to receive methotrexate, whereas there was no significant difference in the rates between 52 participants whose treatment was suspended for 4 weeks after vaccination and those who continued to receive methotrexate.
In an analysis of immunogenic responses to the individual influenza strains, Lee and colleagues found significantly better anti-H3N2 and anti-B-Yamagata responses among patients who suspended methotrexate treatment for 2 weeks before and after vaccination relative to those who continued to receive methotrexate, with increases from baseline of 12.2- versus 5.9-fold and 4.7- versus 2.9-fold, respectively.
These findings suggest that “temporarily discontinuing [methotrexate treatment], especially when the vaccination occurred in the middle of the discontinuation period, significantly increased the efficacy” of the vaccine, say the authors in the Annals of the Rheumatic Diseases.
However, they emphasize that methotrexate discontinuation could increase the likelihood of experiencing active RA, with flares occurring in 34.1% of patients who discontinued treatment for 2 weeks before and after vaccination compared with 24.1% of those who received continuous treatment, although this difference did not reach statistical significance.
The researchers caution that their study was limited by its sample size, and only patients with stable RA and low disease activity were included.
“Further studies testing the generalisability of our results to patients with moderate–high disease activity or with other ethnicities are needed,” they stress.
And the team concludes that although methotrexate discontinuation was associated with an improved humoral vaccine response, “it remains unclear as yet whether a rise in antibody titre actually translates into decreased influenza incidence.”
By Claire Barnard
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