Causal associations between immune cells and psychiatric disorders: a bidirectional mendelian randomization analysis

Area of Science:

• Immunology
• Psychiatry
• Genetics

Background:

• The relationship between immune system activity and psychiatric disorders is increasingly recognized.
• However, establishing a causal link between specific immune traits and mental health conditions remains a significant research challenge.

Purpose of the Study:

• To investigate potential causal relationships between 731 immune cell traits and 11 psychiatric disorders using a bidirectional Mendelian randomization approach.
• To identify specific immune cell subtypes that may influence the risk of developing psychiatric conditions.

Main Methods:

• Utilized summary data from large-scale genome-wide association studies for immune traits and psychiatric disorders.
• Employed two-sample bidirectional Mendelian randomization, including inverse-variance-weighted (IVW), weighted median, and MR-Egger methods.
• Performed sensitivity analyses, including leave-one-out, MR-PRESSO, and MR-Egger intercept tests to assess robustness and rule out pleiotropy.

Main Results:

• Identified several immune cell subtypes with potential causal associations with psychiatric disorders.
• Specifically, certain myeloid cell and B cell subtypes were linked to altered risks for bipolar disorder, schizophrenia, anorexia nervosa, and post-traumatic stress disorder.
• Results were consistent across sensitivity analyses, supporting their validity.

Conclusions:

• This study provides evidence for a causal interplay between specific immune cell traits and the development of psychiatric disorders.
• These findings lay the groundwork for utilizing immune cell profiles as potential biomarkers for early diagnosis and intervention in psychiatric conditions.