Is depression associated with immune activation?

Background: Some research immunologists have suggested that major depression amd chronic fatigue syndrome (CFS) are characterized by immune activation. To test this hypothesis, we compared immunological function in patients with major depression and in patients with CFS who developed major depression after the onset of CFS to that of sedentary healthy controls. Methods: Subjects completed the Centers for Epidemiological Study-Depression (CES-D) questionnaire and allowed venisection. We performed flow cytometric analysis on 13 groups of white blood cells and used a reverse transcriptase PCR method to assay m-RNA of eight cytokines. Results: CES-D scores were high in both patient groups and did not differ significantly. We found no evidence for immune activation in either patient group. Instead the data suggested immunological downregulation in depression. Limitations: Not all the subjects in the two patient groups were off antidepressants. Conclusions: The data indicate that immune activation is not necessary in depression - either alone or with CFS.