Researcher testosterone influences influenza vaccinations

Men respond to a flu shot differently than women

24/12/2013

Women and men often show marked differences in the immune response to vaccinations and infections. A team of researchers from US and French scientists has now analyzed in detail in a recent study these gender differences on the basis of flu vaccination, and identified testosterone as a probable cause of the different immune responses.

To analyze the gender immune response to a flu immunization, the scientists subjected to Mark Davis at Stanford University in California and Boris P. Hejblum from the University of Bordeaux 53 vaccinated women and 34 men vaccinated a thorough investigation. It was „a large number of components of the immune system, including serum cytokines and chemokines, blood cell levels and cellular responses to diverse stimuli“ recorded, the researchers write in the journal „Proceedings of the National Academy of Sciences“ (PNAS). The genetic predisposition of the participants was also taken into account by Davis, Hejblum and colleagues. As part of their research, scientists identified one „Group of genes in lipid metabolism“ (Fat metabolism), which is "apparently related to the diminished immune response of men and whose activity is influenced by testosterone," as described in the study report.

Women show a stronger immune response
According to the researchers, "several previous studies have already shown that men have a weaker immune response than both women after vaccination and after infection." However, the mechanisms that underlie these differences have remained largely unexplained, Davis and Hejblum report. Based on the immune response to a „trivalent inactivated seasonal influenza vaccine“ The researchers have now identified possible causes for the gender-specific differences in the immune response. First, they found that women developed significantly more antibodies than men and that „the expression of proinflammatory cytokines in the serum of women compared to men regardless of age“ much higher. The researchers also identified a cluster of genes involved in lipid metabolism, apparently related to the immune response to the flu vaccine. His activity, according to Davis, Hejblum and colleagues, was closely correlated with testosterone levels in the blood. „Men with elevated serum testosterone levels and the corresponding gene signatures showed the lowest antibody responses“, The researchers continue to report.

Testosterone Cause for a Reduced Men's Immune Response
The results of the current study show "a close relationship between the immune response, the sex hormones (androgens) and the genes involved in lipid metabolism," report Davis and Hejblum. In her opinion, "there are indications that testosterone is the major cause of the different immune responses in men and women". From the evolution the weakening effect of testosterone on the immune response may let explained by the fact that men often suffered injuries while hunting and overreaction of the immune system should be avoided. In terms of in Germany by the Robert Koch Institute (RKI) the recommendations for flu vaccination has the latest findings hardly meaningful, however, raises the question whether should be differentiated in the vaccination does not distinguish between men and women in the future.

Men are actually suffering more?
The results of the study also provide an indication of why men often feel much stronger and longer than harmless women in harmless infections. Because her immune system can set here, due to the high level of testosterone only inadequate to defend. Changes in hormone levels may also have a lasting effect on the immune system, but more studies are needed to clarify the links. (Fp)