White blood cell count at first depression diagnosis as predictor for risk of subsequent hospitalization with depression

Evaluation of Inflammatory Response System (IRS) and Compensatory Immune Response System (CIRS) in Adolescent Major Depression

Purpose

Nowadays, the role of two tightly interconnected systems, the inflammatory response system (IRS) and the compensatory immune response system (CIRS) in depression, is increasingly discussed. Various studies indicate pro-inflammatory activity in adolescent depression; however, there is an almost complete lack of findings about IRS and CIRS balance. Thus, we aimed to assess different IRS and CIRS indices, profiles, and IRS/CIRS ratios in drug-naïve MDD patients at adolescent age, with respect to sex.

Patients and Methods

One hundred MDD adolescents (40 boys, average age: 15.4±1.2 yrs.) and 60 controls (28 boys, average age: 15.3±1.5 yrs.) were examined. Evaluated parameters were 1. plasma levels of interleukin (IL)-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, interferon gamma, tumor necrosis factor alpha (TNF-α), soluble receptor of IL-6 (sIL-6R), soluble receptors of TNF-α (sTNF-R1, sTNF-R2); 2. profiles: IL-6 trans-signaling, M1 macrophage signaling, helper T lymphocytes (Th) 1 profile, regulatory T lymphocytes (Treg)+Th2, allIRS, and allCIRS; 3. IRS vs CIRS activity ratios: TNF-α/TNF-R1, TNF-α/TNF-R2, TNF-α/sTNF-Rs (ie sTNF-R1+sTNF-R2), Th1/Th2, Th1/Treg, Th1/Th2+Treg, M1/Th2, M1/Treg, M1/Treg+Th2, allIRS/allCIRS.

Results

MDD patients showed increased IL-4, IL-10, TNF-α, sIL-6R, Treg+Th2, allIRS, allCIRS, and TNF-α/sTNF-Rs, and decreased Th1/Th2+Treg. MDD females showed increased IL-10 and TNF-α compared to control females. MDD males showed increased IL-4, IL-10, sIL-6R, Treg+Th2, and TNF-α/TNF-R1 compared to control males. Increased sTNF-R1 was found in MDD males compared to MDD females. Positive correlations were found between CDI score and sIL-6R and IL-10 in the total group and between CDI score and IL-10 in adolescent males.

Conclusion

Our study for the first time extensively evaluated IRS and CIRS interactions revealing enhanced pro-inflammatory TNF-α signaling and IL-6 trans-signaling in association with increased IL-10- and IL-4-mediated anti-inflammatory activity in first-episode depression at the adolescent age. Moreover, results reflect the sex-specific simultaneous activation of IRS and CIRS pathways in adolescent depression.

Role of leukocytes, gender, and symptom domains in the influence of depression on hospitalization and mortality risk: Findings from the Moli-sani study

BACKGROUND

Major depressive disorder is a mental illness associated with chronic conditions like cardiovascular disease (CVD). Circulating inflammation has been proposed as a potential mechanism underlying this link, although the role of specific biomarkers, gender, and symptom domains is not well elucidated.

METHODS

We performed multivariable Cox regressions of first hospitalization/all-cause mortality and CVD, ischemic heart (IHD), and cerebrovascular disease (CeVD) causes vs. depression severity in an Italian population cohort (N = 13,191; age ≥ 35 years; 49.3% men; 4,856 hospitalizations and 471 deaths, median follow-up 7.28 and 8.24 years, respectively). In models adjusted for age, sex, and socioeconomic status, we estimated the proportion of association explained by C-reactive protein (CRP), platelet count, granulocyte-to-lymphocyte ratio (GLR), and white blood cell count (WBC). Gender-by-depression interaction and gender-stratified analyses were performed. Associations of polychoric factors tagging somatic and cognitive symptoms with incident clinical risks were also tested, as well as the proportion explained by a composite index of circulating inflammation (INFLA score).

RESULTS

Significant proportions of the influence of depression on clinical risks were explained by CRP (4.8% on IHD hospitalizations), GLR (11% on all-cause mortality), and WBC (24% on IHD/CeVD hospitalizations). Gender-by-depression interaction was significantly associated only with all-cause mortality (p = 0.03), with moderate depression showing a + 60% increased risk in women, but not in men. Stable associations of somatic, but not of cognitive, symptoms with increased hospitalization risk were observed (+ 16% for all causes, + 14% for CVD causes), with INFLA score explaining small but significant proportions of these associations (2.5% for all causes, 8.6% for IHD causes).

CONCLUSIONS

These findings highlight the importance of cellular components of inflammation, gender, and somatic depressive symptoms in the link between depression and clinical (especially CVD) risks, pointing to the existence of additional pathways through which depression may play a detrimental effect on the cardiovascular system.

White blood cell count as a mediator of the relationship between depressive symptoms and all-cause mortality: A community-based cohort study

BACKGROUND AND OBJECTIVES

One possible pathway by which depressive symptoms influence all-cause mortality is through their relationship with markers of inflammatory response. We aimed to examine whether white blood cell (WBC) count mediated the relationship between the presence of depressive symptoms and all-cause mortality among older Chinese people.

METHODS

This community-based cohort study targeted 4053 individuals aged 60 years or over. A bootstrapping approach was applied to examine whether WBC count mediated the relationship between the presence of depressive symptoms and all-cause mortality. WBC count was evaluated as a mediator. The presence of depressive symptoms was assessed by the nine-item Patient Health Questionnaire (PHQ-9). The mediating effect was considered significant if the 95% confidence interval (CI) did not include 0.

RESULTS

Mediation analysis indicated that WBC count played an important mediating role in the relationship between PHQ-9 score and all-cause mortality based on the significance of indirect effect (β = -0.0039, 95% CI = -0.01, -0.0009). The direct effect from PHQ-9 score to all-cause mortality was not statistically significant (P = 0.11) after adjusting for WBC count.

CONCLUSION

WBC count was associated with depressive symptoms and all-cause mortality. The association of depressive symptoms with all-cause mortality was fully mediated by WBC count.

Combined influence of depression severity and low-grade inflammation on incident hospitalization and mortality risk in Italian adults

BACKGROUND

Depression and low-grade systemic inflammation are associated risk factors for hospitalizations and mortality, although the nature of this relationship is under-investigated.

METHODS

We performed multivariable Cox regressions of first hospitalization/mortality for all and specific causes vs depression severity, in an Italian population cohort (N=13,176; age≥35 years; 49.4% men), incrementally adjusting for sociodemographic, health and lifestyle factors. We tested potential mediation, additive and interactive effects of INFLA-score, a composite circulating inflammation index, and potential concurrent mediations of main lifestyles and chronic conditions.

RESULTS

Over 4,856 hospitalizations (median follow-up 7.28 years), we observed an increased incident risk of events by 24% (CI=17-32%) and 59% (30-90%) for moderate and severe depression, which also showed a 125% (33-281%) increased risk of all-cause mortality (over 471 deaths, 8.24 years). These remained stable after adjustment for lifestyles, health conditions and INFLA-score, which explained 2.1%, 7.6%, 16.3% and 8%, 14.9% and 12% of depression influence on hospitalizations and mortality risk, respectively. These proportions remained substantially stable after reciprocal adjustments. INFLA-score showed significant additive (but not interactive) effects on both hospitalizations and mortality risk.

LIMITATIONS

Depression severity was defined using a sub-version of Patient Health Questionnaire 9, which was validated here. Directionality links among exposures could not be established since they were collected simultaneously.

CONCLUSIONS

These findings suggest a combined influence of depression and low-grade inflammation on health, which is partly intertwined and dependent on lifestyles and chronic conditions. This suggests the existence of pathways other than inflammation through which depression may play its detrimental effect.

Potential major depressive disorder biomarkers in pediatric population - a pilot study

Mental disorders affect 10-20 % of the young population in the world. Major depressive disorder (MDD) is a common mental disease with a multifactorial and not clearly explained pathophysiology. Many cases remain undetected and untreated, which influences patients' physical and mental health and their quality of life also in adulthood. The aim of our pilot study was to assess the prediction value of selected potential biomarkers, including blood cell counts, blood cell ratios, and parameters like peroxiredoxin 1 (PRDX1), tenascin C (TNC) and type IV collagen (COL4) between depressive pediatric patients and healthy peers and to evaluate a short effect of antidepressant treatment. In this study, 27 young depressive patients and 26 non-depressed age-matched controls were included. Blood analyses and immunological assays using commercial kits were performed. Platelet count was the only blood parameter for which the case/control status was statistically significant (p=0.01) in a regression model controlling for the age and gender differences. The results from ELISA analyses showed that the case/control status is a significant predictor of the parameters PRDX1 (p=0.05) and COL4 (p=0.009) in respective regression model considering the age and gender differences between MDD patients and controls. A major finding of this study is that values of platelet count, monocyte to lymphocyte ratio, white blood cell, and monocyte counts were assessed by the Random Forest machine learning algorithm as relevant predictors for discrimination between MDD patients and healthy controls with a power of prediction AUC=0.749.