Immunosuppressants render flu vaccination less effective in people with lupus

Lupus Foundation of America

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What is the topic?

The immune system fights off the flu in different ways. One way is by making antibodies (immune proteins) that recognize the flu virus and attack it. Another way is by activating certain white blood cells to fight the virus; this is called “cell-mediated immunity.” Both antibodies and cell-mediated immunity play important roles in the body’s normal response to a flu shot. Lupus patients might have decreased antibody responses to the flu shot as compared to healthy people. Since cell-mediated responses to the influenza vaccine also influence how well the vaccine will work, it is important to understand how lupus may affect the body’s cell-mediated response to the vaccine.

What did the researchers hope to learn?

The researchers wanted to measure the cell-mediated responses (or responses of certain white blood cells) to a flu vaccine in lupus patients.

Who was studied?

54 lupus patients and 54 healthy people, similar in age and about the same percent of women and men, were studied. Most of the lupus patients had relatively few active symptoms. Pregnant women were not studied.

How was the study conducted?

Lupus patients were randomly picked to either get a flu shot or not. All the healthy people got a flu shot. The flu shot was a "subunit" vaccine, meaning that it had parts of the dead flu virus that help to trigger an immune response but was missing other parts of the virus. Blood samples were taken at the beginning of the study and again 28 days later.

What did the researchers find?

As compared to healthy people, lupus patients had less cell-mediated responses to the flu shot, which may have been influenced by the fact that many of them were taking prednisone and/or azathioprine (Imuran) when they got the shot. Influenza vaccination did not increase lupus disease activity, but minor side effects occurred more frequently in lupus patients than in healthy people.

What were the limitations of the study?

This was a small study. Given that there were not that many patients in the first place, the fact that they were taking a wide variety of medications make it difficult to sort out the results. Finally, more of the lupus patients than the healthy people had gotten a flu shot in the previous year, which could have influenced the results when comparing these two groups.

What do the results mean for you?

It may be that lupus patients have decreases in both antibody and cell-mediated responses to the flu shot as compared to most people. This may make it easier for lupus patients to get the flu and harder to fight it off when they do, especially when taking prednisone or other treatments that suppress the immune system. Appropriate caution to prevent the flu should be taken by all lupus patients, such as avoiding contact with infected people and washing hands frequently, even if the flu shot has already been given.

Studies of cell-mediated immune responses to influenza vaccination in systemic lupus erythematosus.
Authors: Holvast A, van Assen S, de Haan A, Huckriede A, Benne CA, Westra J, Palache A, Wilschut J, Kallenberg CG, and Bijl M. (2009).
Arthritis & Rheumatism 60: 2438-2447.