Alopecia areata: a heterogeneous disease?

Type 3 autoimmune polyglandular syndrome (APS-3) or type 3 multiple autoimmune syndrome (MAS-3): an expanding galaxy

BACKGROUND

The number of recognised distinct autoimmune diseases (AIDs) has progressively increased over the years with more than 100 being reported today. The natural history of AIDs is characterized by progression from latent and subclinical to clinical stages and is associated with the presence of the specific circulating autoantibodies. Once presented, AIDs are generally chronic conditions. AIDs have the tendency to cluster and co-occur in a single patient. Autoimmune thyroid diseases (AITD) are the most prevalent of AIDs in the world population, and about one-third of the AITD patients also present with a non-thyroid AID during their life-span. Furthermore, patient with non-thyroid AIDs often presents with a form of AITD as a concurrent condition. Many of the clusters of AIDs are well characterized as distinctive syndromes, while some are infrequent and only described in case reports.

PURPOSE

In this review, we describe the wide spectrum of the combinations and the intricate relationships between AITD and the other AIDs, excluding Addison's disease. These combinations are collectively termed type 3 Autoimmune Polyglandular Syndrome (APS-3), also called type 3 Multiple Autoimmune Syndrome (MAS-3), and represent the most frequent APS in the world populations.

CONCLUSIONS

Numerous associations of AITD with various AIDs could be viewed as if the other AIDs were gravitating like satellites around AITD located in the center of a progressively expanding galaxy of autoimmunity.

HLA-DR expression by hair follicle keratinocytes in alopecia areata: evidence that it is secondary to the lymphoid infiltration

There is evidence suggesting that alopecia areata (AA) may have an autoimmune pathogenesis, and it was recently reported that keratinocytes in the bulb of some hair follicles affected by this condition express class II HLA (HLA-DR) antigens, which are not present on the same cells in normal tissue. Since it has been proposed that an analogous ectopic HLA-DR expression by epithelial cells in other organs might be an early event leading to organ-specific autoimmunity, we have investigated the sequence in which perifollicular mononuclear cell (MNC) infiltration and ectopic HLA-DR expression on keratinocytes appear in recent-onset and long-standing cases of AA by immunostainings of affected and unaffected areas with monoclonal antibodies against leukocyte and HLA-DR antigens. In recent-onset AA lesions, ectopic HLA-DR expression on hair follicle keratinocytes was found only occasionally (in 3 out of 247 follicles examined) and was restricted to biopsies from the affected areas. This prevalence was significantly lower than the prevalence of hair follicles showing perifollicular MNC infiltrates in the same biopsies, and was also significantly lower than the prevalence of hair follicles showing ectopic HLA-DR expression on keratinocytes in the affected areas of longstanding cases. These findings suggest that in AA lesions the perifollicular MNC infiltration precedes the ectopic HLA-DR expression on hair follicle keratinocytes, and therefore argue against the notion of a primary role for that ectopic HLA-DR expression on epithelial cells in triggering the putative autoimmune response in AA.