Monocyte count in schizophrenia and related disorders: a systematic review and meta-analysis.

OBJECTIVE: Increasing evidence suggests that immunological and inflammatory dysfunctions may play an important role in predisposition, onset, and progression of schizophrenia and related psychosis. The activation of cells of the mononuclear phagocyte system, especially microglia and monocytes, has been reported in schizophrenia. We carried out this systematic review and meta-analysis to investigate if there are significant differences in monocyte count comparing healthy controls with people suffering from schizophrenia and related disorders. METHODS: We searched main electronic databases; nine records met all our criteria and were included in the meta-analysis. Meta-analyses based on random effects models have been carried out generating pooled standardised mean differences (SMDs) of monocyte count in peripheral blood between schizophrenia and related psychosis and healthy controls. Heterogeneity was estimated. Relevant sensitivity and subgroup analyses were conducted. RESULTS: Patients showed higher monocyte count as compared with healthy control (SMD = 0.393; p = 0.001). Heterogeneity across studies was from moderate to high (I2 = 65.952%); sensitivity analysis leaving out two studies responsible for most of the heterogeneity showed a slightly higher SMD. Subgroup analyses confirmed this result, showing no significant differences in the effect size across different study characteristics. CONCLUSIONS: Monocyte count can be considered an indirect marker of microglia activation in the central nervous system. Thus, the observed higher monocyte count in patients could be considered as a possible peripheral marker of microglia's activation in schizophrenia disorder.

Neutrophil-lymphocyte ratio, monocyte-lymphocyte ratio and platelet-lymphocyte ratio in non-affective psychosis: A meta-analysis and systematic review.

Objectives: Neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and monocyte/lymphocyte ratio (MLR) are inexpensive and reproducible biomarkers of inflammation. This is the first meta-analysis exploring the role of NLR, MLR and PLR in non-affective psychosis.Methods: Eight studies have been identified from the main electronic databases. Meta-analyses based on random-effects models have been carried out generating pooled standardised mean differences (SMDs) between non-affective psychotic patients and healthy controls (HCs).Results: Subjects with non-affective psychosis had a significant higher NLR and MLR as compared with HC (respectively SMD = 0.715; P < 0.001; I2=57.565% and SMD = 0.417; P = 0.001; I2=65.754%), confirmed by heterogeneity-based sensitivity analysis. Subgroup analyses showed no differences in effect size across different study characteristics, including drug treatment status, diagnosis, and setting. Meta-regression showed that age influenced the relationship between non-affective psychosis and MLR. A trend of significance, not confirmed by heterogeneity-based sensitivity analysis, was observed in PLR with patients showing higher PLR than HC.Conclusions: Our meta-analysis supports the hypothesis that an inflammatory activation occurs in non-affective psychosis and inflammatory ratios, especially NLR and MLR, may be useful to detect this activation.

Neutrophil/lymphocyte ratio and platelet/lymphocyte ratio in mood disorders: A meta-analysis.

The immune and inflammatory system is involved in the etiology of mood disorders. Neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR) and monocyte/lymphocyte ratio (MLR) are inexpensive and reproducible biomarkers of inflammation. This is the first meta-analysis exploring the role of NLR and PLR in mood disorder. We identified 11 studies according to our inclusion criteria from the main Electronic Databases. Meta-analyses were carried out generating pooled standardized mean differences (SMDs) between index and healthy controls (HC). Heterogeneity was estimated. Relevant sensitivity and meta-regression analyses were conducted. Subjects with bipolar disorder (BD) had higher NLR and PLR as compared with HC (respectively SMD = 0.672; p < 0.001; I2 = 82.4% and SMD = 0.425; p = 0.048; I2 = 86.53%). Heterogeneity-based sensitivity analyses confirmed these findings. Subgroup analysis evidenced an influence of bipolar phase on the overall estimate whit studies including subjects in manic and any bipolar phase showing a significantly higher NLR and PLR as compared with HC whereas the effect was not significant among studies including only euthymic bipolar subjects. Meta-regression showed that age and sex influenced the relationship between BD and NLR but not the relationship between BD and PLR. Meta-analysis was not carried out for MLR because our search identified only one study when comparing BD to HC, and only one study when comparing MDD to HC. Subjects with major depressive disorder (MDD) had higher NLR as compared with HC (SMD = 0.670; p = 0.028; I2 = 89.931%). Heterogeneity-based sensitivity analyses and meta-regression confirmed these findings. Our meta-analysis supports the hypothesis that an inflammatory activation occurs in mood disorders and NLR and PLR may be useful to detect this activation. More researches including comparison of NLR, PLR and MLR between different bipolar phases and between BD and MDD are needed.