Immunology and Immunogenetics Insights

Objective: Chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) is a disorder characterized by debilitating fatigue accompanied by pain and impairments in memory, cognition, and concentration. Acetylcholine (ACh) has a plethora of roles in neuronal and neuromuscular transmission. There are two types of ACh receptors, muscarinic and nicotinic, comprising 17 different subunits of the nicotinic ACh receptor (nAChR) and five different subtypes of the muscarinic receptor (mAChR) that have been identified in humans. The purpose of this study was to determine the role of ACh receptor (nAChRs and mAChRs) single nucleotide polymorphisms (SNPs) in CFS/ME patients.

Methods: One-hundred and fifteen CFS/ME patients (age = 48.68 ± 1.06 years) and 90 nonfatigued controls (age = 46.48 ± 1.22 years) participated in this study, where CFS/ME patients were defined according to the 1994 Center for Disease Prevention and Control (CDC) criteria. A total of 464 SNPs for nine mammalian ACh receptor genes (M1, M2, M3, M4, M5, alpha 2, 5, 7, and 10) were examined via the Agena Biosciences iPLEX Gold assay. Statistical analysis was performed using the PLINK analysis software.

Results: Seventeen SNPs were significantly associated with CFS/ME patients compared with the controls. Nine of these SNPs were associated with mAChRM3 (rs4463655; P = 0.00281, rs589962; P = 0.00348, rs1072320; P = 0.00371, rs7543259; P = 0.00513, rs6661621; P = 0.00536 rs7520974; P = 0.0167, rs726169; P = 0.02349, rsrs6669810; P = 0.02361, rsrs6429157; P = 0.0375), while the remainder were associated with nAChR alpha 10 (rs2672211; P = 0.0107, rs2672214; P = 0.0108, rs2741868; P = 0.01185, rs2741870; P = 0.01281, rs2741862; P = 0.03043), alpha 5 (rs951266; P = 0.01153; rs7180002, P = 0.03682), and alpha 2 (rs2565048; P = 0.01403).

Conclusion: The data from this pilot study suggest an association between ACh receptors, predominantly M3 and CFS. ACh receptor SNPs may contribute to the pathomechanism of CFS/ME.