Association between cytokines and symptoms of depression and anxiety in patients with type 1 narcolepsy.

BACKGROUND: Symptoms of depression and anxiety are common complications of narcolepsy. Earlier studies have shown that narcolepsy type 1 (NT1) is an autoimmune inflammatory disease and symptoms of depression and anxiety are closely related to fluctuations in inflammatory cytokines. The objective of the current research was to investigate the potential correlation between cytokines and symptoms of depression and anxiety in patients with NT1. METHODS: We collected demographic and clinical data and information on cytokine levels from 50 patients with NT1 and used Self-Rating Depression Scale (SDS) and Self-Rating Anxiety Scale (SAS) to assess the severity of depression and anxiety symptoms. Patients with SDS scores ≥ 53 points were defined as depressive narcolepsy type 1 (D-NT1) and those with SDS scores < 53 points as non-depressive narcolepsy type 1 (ND-NT1). Patients with SAS scores ≥ 50 points were defined as anxious narcolepsy type 1 (A-NT1) and those with SAS scores < 50 points as non-anxious narcolepsy type 1 (NA-NT1). A binary logistic regression model was employed to identify the influencing factors of depressive and anxiety symptoms. RESULTS: Levels of IL-10 (p = 0.02), IL-4 (p = 0.049) and disease duration (p = 0.049) were decreased, while SAS scores (p < 0.001) and total sleep duration (p = 0.03) were increased in D-NT1 relative to ND-NT1 patients. A-NT1 patients had higher SDS scores (p < 0.001) compared to NA-NT1 patients. Binary logistic regression analysis revealed associations of longer disease duration (OR=0.83; 95 % CI: 0.70-0.97) and increased IL-10 (OR=0.40; 95 % CI: 0.17-0.90) with reduced risk of depression and worsening anxiety (SAS score; OR=1.17; 95 % CI: 1.06-1.30) with increased risk of depression in patients with NT1. Consistently, worsening depression (SDS score; OR=1.22; 95 % CI: 1.07-1.39) was correlated with increased risk of anxiety in the NT1 group. CONCLUSION: Our finding that higher IL-10 levels correlate with a lower risk of depression in NT1 patients provides a reference for further exploration of the pathophysiological mechanisms of depressive symptoms in NT1 patients.

Cell-based vs enzyme-linked immunosorbent assay for detection of anti-Tribbles homolog 2 autoantibodies in Chinese patients with narcolepsy.

STUDY OBJECTIVES: Narcolepsy type 1 is attributed to a deficiency in cerebrospinal fluid orexin and is considered linked to autoimmunity. The levels of anti-Tribbles homolog 2 (TRIB2) autoantibodies are elevated in the sera of some patients with narcolepsy with cataplexy. Additionally, injecting mice with serum immunoglobulin from patients with narcolepsy with positive anti-TRIB2 antibodies can induce hypothalamic neuron loss and alterations in sleep patterns. Consequently, we hypothesized the existence of a potential association between anti-TRIB2 antibodies and narcolepsy. To test this possibility, we used cell-based assays (CBAs) and enzyme-linked immunosorbent assays (ELISAs) to detect the presence of anti-TRIB2 antibodies in Chinese patients with narcolepsy. METHODS: We included 68 patients with narcolepsy type 1, 39 patients with other central disorders of hypersomnolence, and 43 healthy controls. A CBA and a conventional ELISA were used to detect anti-TRIB2 antibody levels in patients' sera. RESULTS: CBA was used to detect serum anti-TRIB2 antibodies in Chinese patients with narcolepsy, and the results were negative. However, when the ELISA was used, only 2 patients with narcolepsy type 1 had TRIB2 antibody titers higher than the mean titer plus 2 standard deviations of the healthy controls. CONCLUSIONS: In our study, ELISA identified TRIB2 autoantibodies in sera of patients with narcolepsy where CBA failed to demonstrate them. Contrary to our hypothesis, this intriguing finding deserves further research to elucidate the potential association between TRIB2 and narcolepsy type 1. Exploring the implications of TRIB2 autoantibodies in narcolepsy and disparate outcomes between ELISA and CBA could provide crucial insights. CITATION: Zhong X, Yuan Y, Zhan Q, et al. Cell-based vs enzyme-linked immunosorbent assay for detection of anti-Tribbles homolog 2 autoantibodies in Chinese patients with narcolepsy. J Clin Sleep Med. 2024;20(6):941-946.