Childhood Sjögren syndrome: insights from adults and animal models

Abstract

Purpose of review: Sjögren syndrome is a chronic autoimmune disease affecting lacrimal and salivary glands that often is accompanied by extraglandular disease manifestations. Although common in adults, the prevalence and prognosis of childhood Sjögren syndrome are unknown, in part due to lack of child-specific diagnostic and classification criteria. This review discusses difficulties in diagnosing childhood Sjögren syndrome and highlights recent findings in Sjögren syndrome treatment and pathogenesis from studies in adults and animal models over the past 18 months.

Recent findings: Studies of rituximab show some therapeutic potential in adult Sjögren syndrome, whereas newer modalities including gene therapy and mesenchymal stem cell transfer are promising. The pathogenesis of Sjögren syndrome is emerging, including roles of T and B lymphocytes, autoantibodies, interferons, and glandular epithelial cells. Specific recent notable findings in Sjögren syndrome pathogenesis include identification of a type II interferon signature in salivary glands of Sjögren syndrome patients, characterization of salivary gland-infiltrating T-cell subsets, and characterization of antimuscarinic acetylcholine receptor type 3 autoantibodies.

Summary: Childhood Sjögren syndrome is a poorly defined and underdiagnosed autoimmune disease that requires child-specific criteria in order to study disease burden and prognosis. Studies in adults and animal models continue to elucidate new potential diagnostic and therapeutic targets, which may be relevant for childhood Sjögren syndrome.

Video abstract: http://links.lww.com/COR/A3.

FIGURE 1

Typical SS focal lymphocytic infiltrate. Hematoxylin and eosin stained section from a formalin-fixed, paraffin embedded lacrimal gland of a 10 week old male nonobese diabetic (NOD) mouse (original magnification 200X). This image depicts a typical focal lymphocytic infiltrate in the periductal and perivascular distribution surrounded by normal acinar tissue. The ducts are present in the upper left and right of the focus, and the blood vessels are in the lower left and right. Similar focal infiltrates are also found in salivary glands of NOD and related mice as well as salivary and lacrimal glands of human SS patients. A focus is defined as a group of at least 50 mononuclear cells, and the focus score (FS) is defined by the number of these lymphocyte-dominant foci per 4 mm² of tissue section.