Dissociation of inflammatory markers and natural killer cell activity in major depressive disorder.

Major depressive disorder is associated with increases in infectious disease risk as well as the incidence of inflammatory disorders. Declines of natural killer (NK) cell activity are reliably found in depression, whereas other studies report evidence of inflammation in depressed patients. The potential association between NK activity and circulating markers of immune activation has not been previously examined in the context of major depression. In this study, we measured levels of NK activity, circulating levels of interleukin-6 (IL-6), soluble interleukin-2 receptor, and acute phase proteins in 25 male patients with current major depressive disorder and 25 age, gender, and body weight comparable controls. As compared to controls, patients with major depressive disorder showed lower NK activity (p = .05) and higher circulating levels of IL-6 (p < .05). Levels of NK activity were not correlated with IL-6 or with other markers of immune activation. The independent effect of depression on inflammatory markers and natural killer immune responses has implications for understanding individual differences in the adverse health effects of major depressive disorder.

Effects of a behavioral intervention, Tai Chi Chih, on varicella-zoster virus specific immunity and health functioning in older adults.

OBJECTIVE: Both the incidence and severity of herpes zoster (shingles) increase markedly with increasing age in association with a decline in varicella-zoster virus (VZV) specific cell-mediated immunity (CMI). This study examined whether a behavioral intervention, Tai Chi Chih (TCC), affects VZV specific immunity and health functioning in older adults who, on average, show impairments of health status and are at risk for shingles. METHODS: Thirty-six men and women (age > or =60 years) were assigned randomly to a 15-week program of TCC instruction (three 45 minute classes per week; N = 18) or a wait list control condition (N = 18). VZV-specific CMI was measured at baseline and at 1-week postintervention. Health functioning (Medical Outcome scale: SF-36) was assessed at baseline, and at 5, 10, and 15 weeks during the intervention, and at 1-week postintervention. RESULTS: In the intent-to-treat sample, VZV-specific CMI increased 50% from baseline to 1-week postintervention in the TCC group (p < 0.05) but was unchanged in the wait list control group. In those who completed the study, 1-week postintervention SF-36 scale scores for role-physical (p < 0.05) and physical functioning (p < 0.05) were higher in the TCC group (N = 14) as compared with controls (N = 17). Older adults who had impairments of physical status at baseline showed the greatest increases of SF-36 role-physical (p < 0.01) and physical functioning (p < 0.001) during the TCC intervention. CONCLUSIONS: Administration of TCC for 15 weeks led to an increase in VZV-specific CMI. Gains in health functioning were found in participants who received TCC and were most marked in those older adults who had the greatest impairments of health status.