Positive and negative mood: Association with natural killer cell activity

Abstract

Negative mood (e.g., emotional distress) is known to affect immune function, but little research has addressed effects of positive mood. In the present study, positive and negative mood (over a day) were examined for their relations to natural killer cell activity (NKCA) in 48 healthy women. Results indicated that women reporting some negative mood (N = 26) had lower levels of NKCA than women who had no negative mood, while those with higher levels of positive mood had higher NKCA. However, as indicated by the significant interaction between positive and negative mood, the relation between positive mood and NKCA depended upon the women's experience of negative mood. Higher levels of positive mood were related to higher levels of NKCA only among the women who reported having some negative mood over the day. These results raise the possibility that positive mood may moderate, or buffer, the effects of negative mood on immune function.