Comparisons of Serum Interleukin-8 Levels in Major Depressive Patients With Drug-Free Versus SSRIs Versus Healthy Controls

Abstract

Objective: The interleukin-8 (IL-8) has been reported to play an important role in depression, which might be modulated by the selective serotonin reuptake inhibitors (SSRIs). Thus, the aim of this study was to investigate serum IL-8 levels, depressive symptom, and their associations in drug-free MDD patients, MDD patients with SSRIs, and healthy controls (HCs).

Methods: Fifty-seven drug-free MDD patients (male/female = 35/22, mean age: 39.24 years), 30 MDD patients with SSRIs (male/female = 11/19, mean age: 39.73 years), and 101 HCs (male/female = 52/49, mean age: 37.38 years) were recruited in this cross-sectional study. Serum IL-8 levels and depressive symptom were assessed using the Flow Cytometer and Hamilton Depression Scale (HAMD). The analysis of variance was used for the comparison between groups. The relationship between serum log₁₀ IL-8 levels and HAMD score was analyzed by Pearson correlation.

Results: Serum log₁₀IL-8 levels were lower in all patients than HCs after controlling for covariates (F = 4.86, p = 0.03). There was significant difference in serum Log₁₀IL-8 levels among three groups after controlling for covariates (F = 14.63, p < 0.001). Serum Log₁₀IL-8 levels in drug-free patients were lower compared to HCs (F = 19.38, p < 0.001) or patients with SSRIs (F = 21.89, p < 0.001) after controlling for covariates. However, there was not difference in serum log₁₀IL-8 levels between patients with SSRIs and HCs after controlling for covariates. Moreover, serum Log₁₀IL-8 levels were negatively correlated with HAMD score in all patients (r = -0.37, p = 0.02). Also, serum Log₁₀IL-8 levels were negatively correlated with HAMD score in drug-free patients (r = -0.74, p = 0.01), but not in patients with SSRIs.

Conclusion: Our data supported that the decline in serum IL-8 levels was association with depression. Moreover, the SSRIs might modulate increased serum IL-8 levels of depression.

Keywords: SSRIs; association; depressive symptom; interleukin-8; major depressive disorder.

FIGURE 1

(A) Serum log₁₀IL-8 levels in all major depressive disorder (MDD) patients were lower in comparison to healthy controls (HCs) after adjusting for covariates (1.86 ± 0.64 vs. 2.03 ± 0.53, F = 4.86, p = 0.03). (B) There was significant difference in serum log₁₀IL-8 levels among three groups after adjusting for covariates (1.65 ± 0.56 vs. 2.27 ± 0.57 vs. 2.03 ± 0.53, F = 14.63, p < 0.001). Serum log₁₀IL-8 levels were significantly lower in drug-free MDD patients in comparison to MDD patients with SSRIs (F = 21.89, p < 0.001) and HCs (F = 19.38, p < 0.001) after adjusting for covariates. However, there was no difference in serum log₁₀IL-8 levels between MDD patients with SSRIs and HCs after adjusting for covariates (F = 3.68, p > 0.05). (C) The significant correlations were found in drug-free MDD patients (r = –0.74, p = 0.01) and all MDD patients (r = –0.37, p = 0.02), but not in MDD patients with SSRIs (r = –0.27, p = 0.15). IL-8, interleukin-8; MDD, major depressive disorder; HCs, healthy controls; SSRIs, selective serotonin reuptake inhibitors; HAMD, Hamilton Depression Scale; ANOVA, analysis of variance; ANCOVA, analysis of covariance.