Interaction between serum inflammatory cytokines and brain-derived neurotrophic factor in cognitive function among first-episode schizophrenia patients

Table 1 Comparison of clinical data and serum inflammatory cytokines and brain derived neurotrophic factor between the schizophrenia and healthy controls groups

Variable	SCZ group (84 cases)	HCs group (80 cases)	χ2/t value	P value
Sex, n (%)			0.216	0.642
Male	40 (48)	41 (51)
Female	44 (52)	49 (49)
Age (years, mean ± SD)	39.09 ± 10.24	40.35 ± 11.11	0.224	0.815
Education years (years, mean ± SD)	13.41 ± 3.35	14.54 ± 4.02	1.121	0.262
Smoking history, n (%)			0.081	0.776
Yes	28 (30)	25 (31)
No	56 (70)	55 (69)
Duration of illness (months, mean ± SD)	9.75 ± 3.42	NA	NA	NA
PANSS score (points, mean ± SD)
Positive symptom score	24.63 ± 1.71	NA	NA	NA
Negative symptom score	20.05 ± 2.09	NA	NA	NA
General pathology score	41.77 ± 2.06	NA	NA	NA
Total score	80.05 ± 4.28	NA	NA	NA
C-BCT cognitive function assessment scores for various dimensions (points, mean ± SD)
Information processing speed	32.95 ± 5.12a	47.58 ± 5.69	17.313	< 0.001
Attention	31.17 ± 7.47a	41.55 ± 7.76	12.073	< 0.001
Working memory	35.01 ± 7.18a	47.071 ± 1.16	8.271	< 0.001
Comprehensive + execution ability	32.31 ± 9.89a	47.30 ± 7.48	12.395	< 0.001
Levels of serum inflammatory factors and BDNF (pg/mL, mean ± SD)
IL-1β	37.08 ± 5.11a	26.95 ± 3.54	14.579	< 0.001
IL-4	30.85 ± 7.59	29.35 ± 4.13	1.558	0.121
IL-6	41.15 ± 5.92a	29.37 ± 7.58	11.104	< 0.001
IL-10	28.76 ± 9.51	26.43 ± 6.58	1.690	0.093
BDNF	1383.98 ± 315.33a	2692.42 ± 301.03	17.711	< 0.001

^aP < 0.001.

SCZ: Schizophrenia; HC: Healthy control; C-BCT: Chinese brief cognitive test; PNASS: Positive and negative symptom scale; BDNF: Brain derived neurotrophic factor; IL: Interleukin; NA: Not available.

Table 2 Correlation analysis between serum brain derived neurotrophic factor levels and inflammatory cytokines and brain derived neurotrophic factor in the schizophrenia group (n = 84)

Serum inflammatory factors	BDNF
	r value	P value
IL-1β	-0.160	0.145
IL-4	0.196	0.073
IL-6	-0.324a	0.003
IL-10	0.080	0.470

^aP < 0.05.

BDNF: Brain derived neurotrophic factor; IL: Interleukin.

Table 3 Correlation analysis between Chinese brief cognitive test scores of various dimensions in the schizophrenia group and serum brain derived neurotrophic factor and inflammatory cytokines (n = 84)

Variable	Information processing speed		Attention		Working memory		Comprehensive + execution ability
	r value	P value	r value	P value	r value	P value	r value	P value
IL-1β	-0.198	0.071	-0.226a	0.039	-0.324a	0.003	-0.284a	0.009
IL-4	0.123	0.266	0.025	0.823	0.089	0.421	0.116	0.294
IL-6	-0.315a	0.004	-0.412b	< 0.001	-0.236a	0.030	-0.386b	< 0.001
IL-10	0.122	0.270	0.161	0.143	-0.025	0.822	0.105	0.343
BDNF	0.290a	0.008	0.189	0.085	0.296a	0.006	0.357b	< 0.001

^aP < 0.05.

^bP < 0.001.

BDNF: Brain derived neurotrophic factor; IL: Interleukin.

Table 4 Multiple linear regression analysis of factors affecting the degree of cognitive impairment in first-episode schizophrenia patients

Dependent variable		Non standardized coefficient		Standard coefficient	t value	P value	95%CI of B
		B	Standard error	β			Lower limit	Upper limit
Information processing speed	Constant	35.834	5.378		6.663	0.000	25.134	46.535
	BDNF	0.002	0.002	0.156	1.396	0.167	-0.001	0.005
	IL-6	-0.173	0.088	-0.218	-2.039	0.046	-0.349	0.003
Attention	Constant	61.450	7.025		8.747	0.000	47.473	75.428
	IL-6	-0.492	0.114	-0.426	-4.329	0.000	-0.718	-0.266
	IL-1β	-0.312	0.155	-0.199	-2.019	0.047	-0.619	-0.005
Working memory	Constant	48.866	9.263		5.276	0.000	30.433	67.300
	IL-1β	-0.230	0.150	-0.155	-1.532	0.129	-0.529	0.069
	BDNF	0.004	0.002	0.192	1.793	0.077	0.000	0.008
	IL-6	-0.350	0.115	-0.321	-3.039	0.003	-0.580	-0.121
Comprehensive + execution ability	Constant	52.628	8.983		5.858	0.000	34.751	70.505
	IL-1β	-0.394	0.146	-0.261	-2.699	0.008	-0.684	-0.103
	BDNF	0.004	0.002	0.209	2.041	0.045	0.000	0.008
	IL-6	-0.362	0.112	-0.327	-3.242	0.002	-0.585	-0.140

BDNF: Brain derived neurotrophic factor; IL: Interleukin.