Introducing polyautoimmunity: secondary autoimmune diseases no longer exist

Area of Science:

• Immunology
• Genetics
• Epidemiology

Background:

• Autoimmune diseases share underlying pathophysiological mechanisms, suggesting common genetic influences.
• Polyautoimmunity is defined as multiple autoimmune diseases in one patient, with multiple autoimmune syndrome (MAS) involving three or more.

Purpose of the Study:

• To investigate the prevalence and patterns of polyautoimmunity in patients with autoimmune diseases.
• To identify factors associated with polyautoimmunity and understand the clustering of specific autoimmune conditions.

Main Methods:

• Analysis of polyautoimmunity in 1,083 patients across four autoimmune disease cohorts.
• Systematic literature review of MAS cases reported between January 2006 and September 2011.
• Clustering analysis to identify hierarchical patterns among coexisting autoimmune diseases.

Main Results:

• Polyautoimmunity was observed in 34.4% of patients.
• Autoimmune thyroid disease (AITD) and Sjögren's syndrome (SS) were the most frequently observed conditions.
• Female gender and a family history of autoimmunity were significantly associated with polyautoimmunity.
• Clustering analysis revealed AITD, systemic lupus erythematosus, and SS as highly hierarchical diseases.

Conclusions:

• The coexistence of autoimmune diseases (polyautoimmunity) is common and exhibits a distinct grouping pattern.
• These findings support the concept of a shared origin for multiple autoimmune disorders.
• The term polyautoimmunity is proposed to encompass this association and its potential common etiology.