Influenza vaccination appears to be safe in patients with quiescent systemic lupus erythematosus, although the overall efficacy of the immunization is decreased in them compared to controls, according to a new study.
In addition, there is a trend toward a further decrease in the vaccine's efficacy among systemic lupus erythematosus (SLE) patients taking azathioprine as compared with several other immunosuppressive drugs, reported Dr. A. Holvast from the University of Groningen, the Netherlands, and colleagues.
The study included 56 SLE patients with quiescent disease, defined as an SLE disease activity index (SLEDAI) of £5. Patients were divided into groups based on their use of immunosuppressive drugs, with 12 using no drugs, 17 using hydroxychloroquine (
All patients, along with 18 healthy controls, were vaccinated in October and November 2003 with Influvac (Solvay Pharmaceuticals Inc.), a trivalent influenza vaccine.
SLEDAI scores measured a mean of 30 days after vaccination did not differ significantly from baseline SLEDAI scores in any of the patient groups, and there were also no significant changes in patient-recorded visual analogue scores—suggesting that vaccination did not induce disease activity. “The immune response to influenza is generated during the first weeks following vaccination,” wrote the authors. “If vaccination were to enhance established autoimmunity, this would be expected to occur particularly during this early period.”
They noted that compared with controls, SLE patients had more systemic side effects of vaccination—although these were all mild. With respect to vaccination efficacy, the authors concluded that “SLE patients appear to have a decreased immune response, compared to healthy controls.”
Using blood samples taken at baseline and at the follow-up visit, the subjects' influenza antibody responses to A/H1N1, A/H3N2, and B/Hong Kong were measured in 3 ways: by assessment of a
Although the GMT increased after vaccination in all subjects and did not differ significantly between patients and controls, the authors suggested this was because prevaccination GMTs were higher in patients than in controls because of the patients' higher rate of vaccination in the previous year (77% vs. 22%).
Compared with controls, SLE patients had significantly fewer seroconversions against A/H1N1 and A/H3N2 (43% vs. 94% and 39% vs. 88%, respectively). SLE patients also had fewer seroconversions to B/Hong Kong, compared with controls (41% vs. 71%), although this difference was marginally significant.
No significant differences could be found overall between patients and controls in terms of the percent of people achieving a postvaccination titer of
After excluding all subjects who had been vaccinated the previous year, they found that significantly fewer SLE patients achieved seroconversions and protective titers to A/H1N1 and A/H3N2. (See seroconversion graph.)
“It is conceivable that SLE patients have an intrinsic [immunologic] defect that results in decreased responsiveness to vaccination,” wrote the authors, adding that the use of immunosuppressive drugs may further decrease the vaccination response in these patients. “SLE patients receiving azathioprine showed a trend towards a decreased immune response against influenza A/H3N2, compared with the other patient groups,” they wrote. “For A/H3N2, SLE patients receiving azathioprine had fewer fourfold titre rises than [did] the other patient groups (P = .041). Furthermore, a smaller proportion of the azathioprine group achieved titres of 40 or greater against A/H3N2 (P = .030), compared with the other patient groups.”(See immune response graph.)
The authors suggested that virosomal vaccines, which generate better cellular immune responses and enhance humoral immune responses, might improve the efficacy of vaccination in SLE patients.
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