Inflammatory myopathy, IgA deficiency, and intestinal malabsorption

Small intestinal biopsy findings consistent with celiac disease in patients with idiopathic inflammatory myopathy: Review of existing literature

BACKGROUND

Case reports have described patients with idiopathic inflammatory myopathies (IIM) and a concurrent diagnosis of celiac disease (CeD) for whom the muscle inflammation (myositis) component of IIM improves after the patients start standard treatment with gluten-free diet (GFD). A connection between IIM and CeD is not commonly recognized.

AIM

In this first systematic review of the topic, we aimed to explore all peer-reviewed publications of IIM cases and concomitant small intestinal biopsy findings consistent with CeD, published after 1975.

METHODS

Systematic literature searches were performed in MEDLINE, PubMed, and EMBASE, supplemented by screening of references and non-systematic searches via Google and Google Scholar.

RESULTS

Altogether 30 cases published between 1976 and 2017 were uncovered. Information about gastrointestinal symptoms prior to CeD diagnosis was available for 19 patients, with 6/19 (32%) reporting no GI symptoms. CeD-related serological data were available in 23/30 patients. Endomysial antibodies were present in 10/18 (56%), while only 2/9 (22%) had antibodies against tissue transglutaminase. Serum antibodies to native gliadin were present in 16/18 (89%). Clinical effects of a GFD on the IIM were reported for 24 patients, with signs of improvement in 14/24 (58%), including three patients with otherwise therapy-resistant inclusion body myositis. Longitudinal follow-up data available from the published studies indicated that 7/24 (29%) remained in clinical IIM remission with GFD as the sole therapeutic intervention.

CONCLUSION

In the IIM cases presented here, duodenal biopsy findings consistent with celiac disease was sometimes present without classical CeD symptoms or positive traditional CeD serology, and in the majority of cases, the IIM improved after introduction of a gluten-free diet. While extra vigilance towards CeD in IIM patients seems warranted, there is need for more research to clarify if GFD has effects on organ systems other than the small intestine in patients with IIM and small intestinal biopsy findings consistent with CeD.

Partial IgA-Deficiency with Increased Th2-Type Cytokines in TGF-β1 Knockout Mice

Though it has been shown that TGF-β1 directs B cells to switch to IgA in vitro, no studies have assessed TGF-β1 effects on mucosal vs systemic immunity in vivo. When the B cell functions of TGF-β1 gene-disrupted (TGF-β1−/−) mice were analyzed, significantly decreased IgA levels and increased IgG and IgM levels in serum and external secretions were observed. Further, analysis of Ab forming cells (AFC) isolated from both mucosal and systemic lymphoid tissue showed elevated IgM, IgG, and IgE, with decreased IgA AFC. A lack of IgA-committed B cells was seen in TGF-β1−/− mice, especially in the gastrointestinal (GI) tract. Splenic T cells triggered via the TCR expressed elevated Th2-type cytokines and, consistent with this observation, a 31-fold increase in serum IgE was seen in TGF-β1−/− mice. Thus, uncontrolled B cell responses, which include elevated IgE levels, a lack of antiinflammatory IgA, and an excess of complement-binding IgG and IgM Abs, will promote inflammation at mucosal surfaces in TGF-β1−/− mice and likely contribute to pulmonary and GI tract lesions, ultimately leading to the early death of these mice.

Pediatric rheumatic diseases

The rheumatic diseases of childhood are a relatively common and extraordinarily diverse group of illnesses; nevertheless, they are at least distantly related by similarities of immunodysregulation. These pathophysiologic relationships are reflected in affected children in similarities of historical, physical, and laboratory data as well as therapeutic intervention.

Myopathy as a presentation of coeliac disease

An eight-year-old girl with symptoms and signs of myopathy subsequently was found to suffer from coeliac disease. The myopathy disappeared on a gluten-free diet. It is suggested that the acquired myopathy may be related to deficiency in fat-soluble vitamin D or E, as a result of protracted steatorrhea.