The HLA system and T-cell subsets in Bell's palsy

Area of Science:

• Immunogenetics
• Neurology
• Human Genetics

Background:

• The exact cause of Bell's palsy (BP) remains unclear, though infectious, immunological, and genetic factors are implicated.
• Previous research suggests a potential genetic predisposition and immune system involvement in Bell's palsy pathogenesis.

Purpose of the Study:

• To investigate the association between human leukocyte antigen (HLA) and T-cell subsets in Mexican Mestizo patients with Bell's palsy.
• To explore the potential role of genetic factors, specifically HLA class I and II alleles, in Bell's palsy susceptibility and resistance.

Main Methods:

• Analysis of blood samples from 92 Mexican Mestizo Bell's palsy patients and healthy controls.
• Investigation of HLA class I (A, B, C) and Class II (DR, DQ) products.
• Quantification of CD3, CD4, and CD8 T-cell subsets during the acute and convalescent phases of Bell's palsy.

Main Results:

• A high prevalence of family history (46%) suggests a genetic basis for Bell's palsy.
• A significant decrease in the DR4 allele (pc = 0.001) was observed, indicating a potential resistance-conferring gene.
• Transient T-cell imbalance in the acute phase: decreased CD3 and CD4 cells, increased CD8 cells, which normalized in the convalescent phase.

Conclusions:

• The DR4 allele may act as a resistance factor against Bell's palsy, with non-DR4 carriers potentially at higher risk.
• The observed T-cell imbalance suggests an immune system dysregulation during the acute phase of Bell's palsy.
• The DR4-linked resistance gene might be associated with a predisposition to T-cell defects in Bell's palsy patients.