Insights into Celiac Disease & Systemic Autoimmune Diseases

The prevalence of celiac disease appears to strongly increase in patients with primary Sjögren’s syndrome (pSS), as well as in patients with systemic sclerosis (SSc). Although no association between celiac disease and systemic autoimmune diseases has been documented, rheumatologists know very little about the immunopathogenic basis of that relationship. In the case of pSS, researchers have proposed that environmental factors promote abnormal immune responses, mononuclear cell infiltration and organ damage in the target tissues of the exocrine gland and the small bowel.

Recent research reinforces the increased incidence of celiac disease in patients with pSS and diffuse SSc, suggesting celiac disease screening should be performed in patients with these autoimmune diseases. The findings by Elena Bartoloni, MD, associate professor of rheumatology at the University of Perugia, Italy, and colleagues indicates that such screening may be especially beneficial to young patients at the time of diagnosis of rheumatologic diseases. The investigators published their research online April 19 in the Journal of Clinical Medicine.¹

The study included a population of patients with systemic lupus erythematosus (SLE, n=580), pSS (n=354) and SSc (n=524), as well as healthy controls (n=14,298). In addition to looking for previous diagnoses of celiac disease, the investigators performed systematic screenings for undiagnosed celiac disease, identifying individuals who had high concentrations of IgA and anti-tTG (tissue transglutaminase).

The investigators found an overall celiac disease prevalence of 2.9% in the total systemic autoimmune disease patient group compared with 0.64% in the controls. The prevalence of celiac disease was 1.72% in SLE patients, 7.06% in pSS patients and 1.34% in SSc patients. Patients with diffuse cutaneous SSc had a prevalence of 4.5%, which led the researchers to conclude that the association of celiac disease with diffuse as opposed to limited SSc may indicate that the two subsets of SSc have different immunopathogenic mechanisms.

Often, patients with celiac disease experienced abdominal distention, as well as chronic diarrhea and loss of appetite. Additionally, many of the patients with both SLE and celiac disease displayed a wider autoantibody repertoire in comparison with patients with celiac disease who did not have SLE. In almost half of the patients, a diagnosis of celiac disease came within three years of a diagnosis of autoimmune disease.

“We are aware that the age of [celiac disease] or [systemic autoimmune disease] diagnosis may not correspond to the actual disease onset, and we cannot draw definitive conclusions about the relationship between the two disorders or the consequent pathogenic implications,” write the authors in their discussion. “However, in agreement with the results of other studies, [celiac disease] diagnosis usually preceded the diagnosis of [a systemic autoimmune disease] in the majority of our patients, thereby, suggesting celiac disease as predisposing risk factor for [systemic autoimmune disease] development. Moreover, in agreement with a previously published study, we found the age of both pSS and SSc patients with [celiac disease] was lower than that of the correspondent patient group without [celiac disease], thereby, supporting the idea that [celiac disease] may be able to promote and accelerate [systemic autoimmune disease] development.”