Tumor Necrosis Factor-alpha (TNF-α) −238 G/A Polymorphism Is Associated with the Treatment Resistance and Attempted Suicide in Schizophrenia

ABSTRACT

Abnormality of the immune system may play an important role in the pathogenesis of schizophrenia (SCZ). We aim to investigate the relationship between clinical features of SCZ and tumor necrosis factor-alpha (TNF-α) −238 G/A, −308 G/A polymorphisms in SCZ patients by comparing genotype distributions of TNF-α gene polymorphisms between patients and healthy controls. A sample of 113 patients with SCZ and 104 healthy volunteers was included in the study. SCID-I was used to confirming the diagnosis according to DSM-IV-TR criteria. We evaluated the patients with some scales and data forms in terms of clinical features, symptom severity, level of insight, suicidal behavior, and treatment response. PCR-RFLP was used to determine TNF-α gene polymorphisms from DNA material. The distributions of TNF-α − 238 G/A and TNF-α − 308 G/A polymorphisms of the patients diagnosed with SCZ were not significantly different from the control group. There was a significant difference in the TNF-α − 238 G/A genotype distributions between treatment-resistant and treatment-responsive SCZ patients. Again, the distributions of TNF-α − 238 G/A genotype of attempted suicide patients in SCZ were significantly different from the non-attempted suicide of SCZ patients. Whereas TNF-α − 238 G/A and −308 G/A polymorphisms were not associated with SCZ, TNF-α − 238 G/A polymorphism may be related to treatment resistance and attempted suicide in SCZ patients in the Turkish population.

KEYWORDS:

• Schizophrenia
• tnf-α
• single nucleotide polymorphism
• treatment resistance
• attempted suicide

Contributions of authors

HMA and SP are responsible for the formulation of overarching research goals and aims. HMA, FCT, and KÖ conceived and designed the study. SP, FCT, and KÖ are the responsible provision of study materials and laboratory samples. HMA, MP gained, analyzed, and interpreted all data. HMA drafted the manuscript. All authors critically revised the manuscript. SP, KÖ, and MP supervised the study.

Data Availability Statement

The authors confirm that all relevant data are included in the article which does not contain any supplementary material.

Disclosure statement

All authors declare not to have any conflicts of interest that might be interpreted as influencing the content of the manuscript.

Ethical Approval

The authors declare that all methods contributing to this work comply with the ethical standards of the relevant national and institutional committees on human experimentation and with the Helsinki Declaration of 1975, as revised in 2008 (Williams 2008).

Informed consent

We obtained informed consent from all individual participants included in the study.

Additional information

Funding

The authors received no specific funding for this work.