Association between cytokines and psychiatric symptoms in chronic fatigue syndrome and healthy controls

Figures & data

Table 1. Differences in psychometric evaluation between the two groups.

Parameter	CFS/ME (n = 20)		Control (n = 20)		p Value
	Mean	SD	Mean	SD
HADS total	11.65	6.48	3.85	2.01	.000**
HADS-A	5.80	3.81	3.20	1.94	.026*
HADS-D	5.85	4.32	0.65	0.99	.000**
SCL-90-R somatisation	1.41	0.65	0.25	0.37	.000**
SCL-90-R obsessive–compulsive	1.34	0.47	0.36	0.25	.000**
SCL-90-R interpersonal sensitivity	0.46	0.50	0.12	0.13	.010*
SCL-90-R depression	1.01	0.45	0.22	0.27	.000**
SCL-90-R anxiety	0.43	0.46	0.14	0.19	.016*
SCL-90-R hostility	0.37	0.34	0.09	0.13	.012*
SCL-90-R phobic anxiety	0.14	0.25	0.07	0.14	.627
SCL-90-R paranoid ideation	0.20	0.32	0.08	0.11	.444
SCL-90-R psychoticism	0.14	0.15	0.04	0.06	.012*
SCL-90-R additional items	1.07	0.58	0.25	0.25	.000**
SCL-90-R GSI	0.72	0.29	0.17	0.16	.000**
Fatigue score	25.45	5.10	10.90	3.71	.000**
NRS pain	4.32	1.60	1.00	1.17	.000**

Note. Mann–Whitney U tests. Fatigue score: Chalder Fatigue Scale; GSI: Global Severity Index; HADS: Hospital Anxiety and Depression Scale; NRS: Numeric Rating Scale; SCL-90-R: Symptom Checklist-90-Revised.

* p ≤ .05; **p < .001.

Table 2. Differences in cytokines between the two groups.

Parameter	CFS/ME (n = 20)		Control (n = 20)		p Value
	Median	Range	Median	Range
IL-4	0.04	0.05	0.04	0.08	.583
IL-6	0.69	12.68	0.65	1.66	.314
IL-10	0.93	1.27	1.05	4.78	.194
TNF-α	1.41	5.19	1.08	3.05	.056

Note. Mann–Whitney U tests. Cytokine concentrations are expressed in pg/mL. For IL-10 in the control group: n = 19.

Table 3. Spearman’s ρ correlations between cytokines and fatigue, pain and HADS.

Group	Parameter	Fatigue score	NRS pain	HADS total	HADS-A	HADS-D
Total sample	IL-4	.09	.07	.04	−.01	.11
	IL-6	.07	.14	−.10	−.07	−.08
	IL-10	−.09	−.06	−.20	−.12	−.22
	TNF-α	.21	.26	.36*	.12	.46**
Control	IL-4	.34	−.01	.27	.06	.35
	IL-6	−.25	−.18	−.14	−.02	−.33
	IL-10	.01	.24	0.00	.11	−.04
	TNF-α	−.19	.05	.37	.17	.58*
CFS/ME	IL-4	−.22	−.01	−.31	−.17	−.26
	IL-6	.12	.20	−.39	−.27	−.28
	IL-10	.20	.30	−.29	−.19	−.19
	TNF-α	.17	.05	−.01	−.18	.23

Note. Spearman’s ρ are given. Cytokine concentrations are expressed in pg/mL. Fatigue score: Chalder Fatigue Scale; NRS: Numeric Rating Scale; HADS: Hospital Anxiety and Depression Scale; HADS-A: HADS anxiety; HADS-D: HADS depression.

^* p ≤ .05; ** p ≤ .01.