Hair loss and autoimmunity

A paper just published in the prestigious journal Nature defines the type of autoimmune dysregulation that causes alopecia areata, a common type of hair loss, by determining the underlying genetic expression.

"Alopecia areata (AA) is among the most highly prevalent human autoimmune diseases, leading to disfiguring hair loss due to the collapse of immune privilege of the hair follicle and subsequent autoimmune attack. The genetic basis of AA is largely unknown."

The authors undertook a search through the whole genome and identified 139 polymorphisms significantly associated with AA. They were able to:"...show an association with genomic regions containing several genes controlling the activation and proliferation of regulatory T cells (Treg cells), cytotoxic T lymphocyte-associated antigen 4 (CTLA4), interleukin (IL)-2/IL-21, IL-2 receptor A (IL-2RA; CD25), etc..."This is not only a reminder that hair loss can be autoimmune in nature, but that clinicians mustn't be misled that an autoimmune disease is either an expression of innate immunity (Th1) or acquired immunity (Th2) but not both:

"This study provides evidence for the involvement of both innate and acquired immunity in the pathogenesis of AA. We have defined the genetic underpinnings of AA, placing it within the context of shared pathways among autoimmune diseases..."

This understanding is critical for the functional approach to managing these conditions.