0000000000425222
AUTHOR
K.v. Toyka
The PTPN22gain-of-function+1858T(+) genotypes correlate with low IL-2 expression in thymomas and predispose to myasthenia gravis
Protein tyrosine phosphatase, non-receptor type 22 (PTPN22) inhibits T-cell activation and interleukin-2 (IL-2) production. The PTPN22(gain-of-function)+1858T(+) genotypes predispose to multiple autoimmune diseases, including early-onset (non-thymomatous) myasthenia gravis (MG). The disease association and the requirement of IL-2/IL-2 receptor signaling for intrathymic, negative T-cell selection have suggested that these genotypes may weaken T-cell receptor (TCR) signaling and impair the deletion of autoreactive T cells. Evidence for this hypothesis is missing. Thymoma-associated MG, which depends on intratumorous generation and export of mature autoreactive CD4(+) T cells, is a model of au…
Glucocorticoid-sensitive hereditary inclusion body myositis.
We report a hereditary muscle disorder with features of inclusion body myositis (IBM) in two adult sisters with slowly progressive asymmetrical muscle weakness. The findings of light microscopic and ultrastructural investigations of muscle biopsy specimens were consistent with a diagnosis of IBM. Both patients improved and stabilized on immunosuppressive treatment with corticosteroids and azathioprine. This differentiates our patients from other sporadic and familial cases of IBM. Clinical and histological features are described and compared with those of other previously reported families with IBM.
Deficiency of the autoimmune regulator AIRE in thymomas is insufficient to elicit autoimmune polyendocrinopathy syndrome type 1 (APS‐1)
Thymomas are thymic epithelial neoplasms, associated with a variety of autoimmune disorders (especially myasthenia gravis), that apparently result from aberrant intra-tumourous thymopoiesis and export of inefficiently tolerized T-cells to the periphery. The autoimmune regulator (AIRE) drives the expression of self-antigens in the thymic medulla and plays an essential role in ‘central’ tolerance in both humans and mice. However, while inactivating AIRE mutations result in the ‘autoimmune polyendocrinopathy syndrome type 1’ (APS-1), its major features are not well reproduced in AIRE-knock-out mice. Therefore, alternative human disease scenarios with concomitant AIRE deficiency may be valuable…