Neutrophil-to-Lymphocyte, Platelet-to-Lymphocyte and Monocyte-to-Lymphocyte Ratio in Bipolar Disorder.

Laura Fusar-Poli,Eugenio Aguglia,Patriciu Cimpoesu,Andrea Amerio,Antimo Natale,Gianluca Serafini,Pietro Grimaldi Filioli,Mario Amore,Andrea Aguglia

doi:10.3390/brainsci11010058

Abstract

Background: Several inflammatory hypotheses have been suggested to explain the etiopathogenesis of bipolar disorder (BD) and its different phases. Neutrophil-to-lymphocyte (NLR), platelet-to-lymphocyte (PLR), and monocyte-to-lymphocyte (MLR) ratios have been proposed as potential peripheral biomarkers of mood episodes. Methods: We recruited 294 patients affected by BD, of which 143 were experiencing a (hypo)manic episode and 151 were in a depressive phase. A blood sample was drawn to perform a complete blood count. NLR, PLR, and MLR were subsequently calculated. A t-test was performed to evaluate differences in blood cell counts between depressed and (hypo)manic patients and a regression model was then computed. Results: Mean values of neutrophils, platelets, mean platelet volume, NLR, PLR, and MLR were significantly higher in (hypo)manic than depressed individuals. Logistic regression showed that PLR may represent an independent predictor of (hypo)mania. Conclusions: Altered inflammatory indexes, particularly PLR, may explain the onset and recurrence of (hypo)manic episodes in patients with BD. As inflammatory ratios represent economical and accessible markers of inflammation, further studies should be implemented to better elucidate their role as peripheral biomarkers of BD mood episodes.

Highlights

Bipolar disorder (BD) is a chronic psychiatric disorder characterized by the alternation of different phases, hypomanic/manic and major depressive episodes
Two-hundred ninety-four bipolar inpatients were enrolled in the present study, of which 151 (51.4%) were experiencing a current major depressive episode and 143 (48.6%) a currentmanic episode
We found that neutrophils, platelets, platelet-to-lymphocyte ratio (PLR), Neutrophil-to-lymphocyte ratio (NLR), and monocyteto-lymphocyte ratio (MLR) were significantly higher in patients experiencing a manic episode than depressed individuals

Summary

Introduction

Bipolar disorder (BD) is a chronic psychiatric disorder characterized by the alternation of different phases, hypomanic/manic and major depressive episodes. Patients with BD type I have experienced at least one manic episode (defined as an abnormally elevated mood or irritability and related symptoms with severe functional impairment or psychotic symptoms for seven days or more), with or without major depressive episodes. Patients with BD type II have experienced at least one hypomanic episode (defined as abnormally elevated mood or irritability and related symptoms with decreased or increased function for four days) and one major depressive episode [2]. Immunity and inflammatory imbalance may affect mental functioning from the earliest stages of neural development [5,6] This notion is supported by the fact that various medical conditions characterized by chronic inflammation are associated with the onset and progression of BD [7]. As inflammatory ratios represent economical and accessible markers of inflammation, further studies should be implemented to better elucidate their role as peripheral biomarkers of BD mood episodes

Methods

Results

Discussion

Conclusion