Certain medications could explain diminished protection, researchers say
THURSDAY, July 30 (HealthDay News) -- The two prime means by which the seasonal influenza vaccine activates the immune system against the virus appear to be diminished in people with lupus, a new study finds.
According to Dutch researchers led by Albert Holvast, of the University of Groningen, the human immune system goes on alert against the seasonal flu virus after vaccination in two ways. First, it generates antibodies specifically reacting to the flu virus, and secondly, it primes certain immune T-cells to respond to the flu bug.
Prior work had already shown that the antibody-mediated vaccine response was dimmed in lupus patients, and the new study, involving 54 patients with lupus and 54 healthy controls, replicated those findings.
But the study, published in the August issue of Arthritis & Rheumatism, also found that the activity of those T-cells key to immunization were diminished in lupus patients who received the flu shot vs. immunized healthy controls. This dip in cell-mediated responses was linked to the use of the medications prednisone and/or azathioprine, the researchers added.
Flu vaccination did not impact lupus disease activity, the team said.
"Clinicians should be aware that this combined defect might increase the morbidity and mortality due to influenza virus infection, in particular in patients receiving prednisone and/or azathioprine," the researchers advised. They also called for more investigation into whether alternate flu vaccination strategies might offer better protection to people with lupus.
There's more on lupus at the Lupus Foundation of America.
-- E.J. Mundell
SOURCE: Arthritis & Rheumatism, news release, July 30, 2009
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