Proinflammatory cytokines have been linked to depression and interpersonal interactions are known risk factors for inducing stress and depression. In this study Chiang and coworkers examined whether daily social interactions predict levels of proinflammatory cytokines IL-6 and tumor necrosis factor-alpha soluble receptor, as well as their reactivity to a social stressor. Human subjects were given laboratory stress challenges, and IL-6 and tumor necrosis factor-alpha soluble receptor levels in oral mucosal transudate were measured at baseline, and at 25 and 80 minutes post-stressor. The authors found that daily social interactions that are negative and competitive are predictive of heightened proinflammatory cytokine levels. Although chronic stressor studies remain to be done, the authors suggest that sustained increases in proinflammatory cytokines may affect mental and physical health outcomes related to inflammatory processes.

Chiang JJ, Eisenberger NI, Seeman TE and Taylor SE: Negative and competitive social interactions are related to heightened proinflammatory cytokine activity. Proc. Natl. Acad. Sci. USA [Epub ahead of print, January 23, 2012; doi: 10.1073/pnas.1120972109].

http://www.pnas.org/content/early/2012/01/13/1120972109.abstract