Immune consequences of the spontaneous pro-inflammatory status in depressed elderly patients.

INTRODUCTION

The aim of the study was to describe the interrelationship between senescence, depression, and immunity.

METHODS

We assessed 10 elderly patients with depression and 10 age- and sex-matched controls: before, at one and at six month intervals after the anti-influenza vaccination. Levels of TNFalpha, IL6, ACTH, and cortisol, titres of anti-hemagglutinins and anti-neuraminidases, lymphocytes secreting IFNgamma, IL2, IL4, and IL10, cytotoxicity of NK and CD3+ CD8+ IFNgamma+ cells, anti-CMV antibodies, and CD28- CD57+ lymphocytes known to be associated with the CMV carrier status were evaluated.

RESULTS

Higher levels of anti-CMV, higher percentage of the CD28- CD57+ cells, and elevated levels of TNFalpha, IL6, and cortisol concomitant with decreased levels of ACTH and insufficient production of IL10 (which increased the IFNgamma+ /IL10+ ratio) were found in the patients suffering from depression, in comparison to healthy controls. The subjects with depression revealed a low NK cytotoxicity, while a level of CD3+ CD8+ IFNgamma+ cells was comparable between the groups. Although the levels of anti-hemagglutinins and anti-neuraminidases were low in the depressed patients, they reached the protective titres. The majority of these differences disappeared when CMV titres were entered into the analyses as a covariate.

DISCUSSION

The results suggest that the elderly depressed patients were characterised by increased exposure to CMV in the past, which could have resulted in a pro-inflammatory profile demonstrated as elevated levels of TNFalpha, IL6 and deficiency of suppressive IL10+ cells. These changes negatively affect humoral and innate response in the depressed patients.