Increases in salivary lysozyme and IgA concentrations and secretory rates independent of salivary flow rates following viewing of a humorous videotape

Several studies have shown increases in salivary, secretory IgA (sIgA) levels following exposure to humor and various relaxation strategies. However, the use of sIgA as a marker of immunocompetence has been questioned. In this study we investigated the potential of an alternative marker, salivary lysozyme (sLys) in addition to sIgA. sIgA and sLys concentrations and secretion rates were measured from saliva samples collected immediately prior to and after viewing a humorous (situation comedy) and a control videotape (documentary). sLys concentrations and secretion rates were significantly increased after viewing of the humorous videotape (p =.0007 and p = .009, respectively) but not following viewing of the control video. Similarly, increases were obtained for sIgA (p = .01 and p = .05) following viewing of the humorous tape. sIgA concentration decreased following viewing of the control tape (p = .05). Salivary flow rates did not significantly change following the viewing of either the humorous or the control tapes. Changes following the humorous video were significantly different from changes following the control video for both sLys and sIgA levels (concentration, p = .007 and p = .005; secretory rate, p = .02 and p = .03), but not for salivary flow rates. The results suggest an enhancement of the innate and specific mucosal immune parameters following exposure to humor, independent of salivary flow. Use of sLys may serve as a useful additional or alternative marker of the effects of humor on mucosal immunity.