The Effect of Interleukin-2 -330 T/G Polymorphism in People with Schizophrenia Among The Batak and Javanese Ethnic Groups

Background: Schizophrenia is a complex disorder involving multiple genes with mild to moderate effects and non-genetic risk factors such as environmental and psychological influences that alter brain chemistry. Significant reduction in interleukin-2 production by peripheral lymphocytes is an immunological finding replicated in schizophrenia across various countries. Investigations on the interleukin-2 -330 T/G polymorphism in people with schizophrenia (PWS) are still minimal, and the study location involves only a few countries with different results. Therefore, this study aims to examine the effect of interleukin-2 -330 T/G polymorphisms in people with schizophrenia among the Batak and Javanese ethnic groups in Indonesia, particularly in North Sumatra.

Method: This study used purposive non-probability sampling to recruit people with schizophrenia with 120 Batak and 120 Javanese subjects who were hospitalized at Prof. M. Ildrem Mental Hospital, Medan, Indonesia. The interleukin-2 -330 T/G polymorphism was examined by the PCR method.

Result: The results showed that the genotype frequency of the Batak people with schizophrenia is as follows: GG 11.7%, TG 53.3% and TT 35%. Furthermore, the group of Javanese people with schizophrenia is as follows: GG 23.3%, TG 44.2% and TT 32.5%. The OR for the genotypic comparison of GG was found to be 2.154 with 95% CI 0.992-4.678, p=0.053, while that of the TG genotype was 0.892 with 95% CI 0.505-1.574 and p=0.693. The T allele was higher than the G allele in Batak and Javanese ethnic groups, as demonstrated by p=0.713, OR=0.919 with 95% CI 0.641-1.318.

Conclusion: There is no statistically significant difference between the occurrence frequency of alleles. In addition, there is no significant relationship between the GG and the TG genotype of the interleukin-2 - 330T/G polymorphism in people with schizophrenia among the Batak and the Javanese ethnic groups.