Elevated plasma levels of IL-12 strongly correlate with a higher percentage of non-classical monocytes and more activated classical monocytes in the blood of patients with Major Depressive Disorder

ANGELES ARENA; LEANDRO GRENDAS; DEMIÁN RODANTE; WANDA NOWAK; EUGENIO ANTONIO CARRERA SILVA; FEDERICO DARAY; ANDREA E. ERRASTI

Mar del Plata

Congreso; LXIII Reunión Anual de la Sociedad Argentina de Investigación Clínica- LXVI Reunión Anual de la Sociedad Argentina de Inmunología- Reunión Anual de la Sociedad Argentina de Fisiología; 2018

Sociedad Argentina de Investigación Clínica- Sociedad Argentina de Inmunología- Sociedad Argentina de Fisiología

Major Depressive Disorder (MDD) is a prevalent and disabling condition that comprises a set of pleomorphic syndromes with emotional, cognitive, visceral and behavioral symptoms domains.Despite the public impact of depression its etiology remains unknown. However, in the last years, evidences suggesting the role of the innate and the adaptive immune system in MDD have emerged.Monocyte-macrophage lineage orchestrates the initiation and resolution phases of innate and adaptive immunity, with significant impact on protective immunity and immune-mediated pathological damage. Monocytes can be defined in three populations as classical (CD16negCD14bright), intermediate (CD16+CD14+) and non-classical (CD16brightCD14neg)subsets. Several studies have shown that non-classical monocytes are increased in patients with inflammation processes and infectious diseases. We aimed to characterize the plasma levels of IL-12 and IL-6 together with the monocyte subsets distribution and their activation status in patients with MDD. Blood samples were obtained from patients enrolled in a multicenter prospective cohort study approved by the IRB.Written informed consent was obtained for all participants. In asampleof patients with MDD and no other medical illnessor substance abuse (N=33), 36% of patients showed higher levels of IL-12 and 54% of patients higher levels of IL-6compared with a matched distribution of age and gender healthy control group (N=20). Furthermore, 27% of patients exhibited increased levels of both cytokines. Interestingly, a significant increase of non-classical monocytes fraction in patients with MDD positively correlatedwith higher levels of IL-12 (r=0.51, p