The NF-kappaB pathway regulates the expression of over 150 target genes, e.g., cytokines, chemokines, leukocyte adhesion molecules and inducible effector enzymes. Consequently, it plays a crucial role in innate and adaptive immune responses, inflammatory response, stress responses, apoptosis and so on. IkappaB kinase (IKK) is the key of this pathway, and it owns a special structure which consists of catalytic subunit and regulatory subunit. Naturally, the activation of IKK needs the interaction of the two subunits and phosphorylation by its upstream kinases. Actually, there are two methods of activation of the NF-kappaB pathway, and both of the methods need the IKK complex. Given to the crucial role of IKK, researchers have isolated and synthesized amounts of IKK inhibitors, and these provide a great convenience to develop novel anti-inflammatory and anti-tumor drugs.

Objective:To explore the relationship between somatic symptoms of major depressive disorder(MDD)and cortisol(COR) rhythm, C-reactive protein(CRP) and other immune-metabolism-related indicators, and understand its mechanism from the perspective of endocrine and immune regulation.Methods:A case-control study was conducted in hospitalized patients with MDD who met DSM-5 diagnostic criteria.According to the Patient Health Questionnaire (PHQ-15), PHQ-15 ≥10 were classified as the somatic major depressive disorder group(S-MDD group) and 73 patients were enrolled.PHQ-15 <5 was classified as the non-somatic depressive disorder group (NS-MDD group) and 70 patients were enrolled.Plasma cortisol (COR8, COR16 and COR24) levels were measured at 8∶00, 16∶00 and 24∶00 on the same day, plasma CRP and interleukin-6 (IL-6) level, serum uric acid (UA), blood glucose (GLU), blood lipid (TC, TG, HDL, LDL) level were detected at 8∶00.Independent sample t test, non-parametric test, chi-square test, repeated ANOVA, covariance analysis, and multivariate Logistic regression were used for statistical analysis. Results:①Time effect, grouping effect and the interaction effect of the time and grouping in the level of COR were statistically significant ( P<0.05). Covariance analysis excluded age as an influential factor, COR16, AUC(total cortisol output/area under the curve, AUC) and COR8-16 in S-MDD group ((90.50±40.57)μg/L, (1 425.12±564.78), (-6.43±5.76))were higher than those in NS-MDD group((68.74±31.51)μg/L, (1 251.57±456.61), (-8.77±5.48)), and the difference was statistically significant ( F=8.971, 4.320, 8.731, P<0.05). ②CRP in S-MDD group ((1.41±1.06)mg/L) were higher than that in NS-MDD group((0.61±0.53)mg/L), and the difference was statistically significant ( F=25.436, P<0.05). The proportion of patients with higher CRP level(CRP≥1 mg/L) in S-MDD group(58%) was higher than that in NS-MDD group(23%), and the difference was statistically significant(χ 2=17.824, P<0.01). ③Multivariate logistic regression analysis found that CRP ( OR=4.953, 95% CI: 2.407-10.193), COR8-16 ( OR=3.451, 95% CI: 1.380-8.633) were main risk factors of somatic symptoms of MDD ( P<0.05). Conclusion:Cortisol rhythm disturbance and high CRP level may be the biological basis of somatic symptoms in patients with MDD.