Myasthenia gravis induced by alpha-interferon therapy

Myasthenia Gravis and Myeloproliferative Neoplasms - Mere Association or Paraneoplastic Neurologic Syndrome: A Mini-Review

Myasthenia Gravis (MG) is a rare neurological condition characterized by muscle weakness that worsens after use. Myeloproliferative Neoplasms (MPNs) are disorders due to stem-cell hyperplasia characterized by an increased peripheral blood cell count, overactive bone marrow, and proliferation of mature hematopoietic cells. MPNs may be Philadelphia (Ph) chromosome-positive or Negative .A systematic review of case reports was conducted by searching PubMed, Scopus, and Google scholar to identify case reports in which there is an association between MG and MPN and know whether MG can be considered a possible neurological paraneoplastic syndrome in patients with MPNs. A total of 13 cases of MPNs associated with MG were identified. The most common type of MPN associated with MG was chronic myeloid leukemia (CML) (10 out of 13 patients).  In most of the patients, MG symptoms appeared after a diagnosis of MPN was made. Considering that 10 out of the 13 patients in our cohort had positive auto-antibodies though only 4 of them had thymic hyperplasia, we hypothesize that bone marrow proliferation was responsible for the production of autoantibodies in these patients.As the clonal cell population cannot be eliminated entirely in the bone marrow even after treatment with tyrosine kinase inhibitors (TKI) in Ph +ve MPNs and JAK2 inhibitors in Ph -ve MPNS, MG can occur even in patients who are treated with these agents. A high index of suspicion is needed to diagnose it early, and treatment should be initiated immediately with steroids and anticholinergic agents.

Development of Myasthenia Gravis in a Patient with Chronic Myeloid Leukemia during Treatment with Nilotinib

We report on a patient diagnosed with chronic myeloid leukemia (CML) who developed myasthenia gravis while on treatment with nilotinib. Autoimmune disease, including the development of myasthenia gravis, has been described in association with CML as well as the use of tyrosine kinase inhibitors. Second generation tyrosine kinase inhibitors are highly effective in the treatment of CML, although can result in adverse effects related to off-target kinase inhibition, and longer term reporting of adverse effects is required.

Interferon-induced sarcoidosis

Interferons (IFNs) are widely used for the treatment of various medical diseases. They have marked immunomodulatory effects, and many reports have been published associating IFN therapy with the induction of autoimmune phenomena and other disorders of immune regulation such as sarcoidosis. The clinical presentation of IFN-induced sarcoidosis (IIS) is insidious and can be confused with common constitutional side effects of these drugs. The age of onset of IIS is later than that of naturally occurring sarcoidosis. The most common organs involved are the lungs and skin. In the majority of cases, IIS follows a benign course. As we show in an illustrative case report, complete resolution after discontinuation of IFN therapy can be expected. This review summarises 65 cases of IIS reported in the literature and highlights the pathophysiology, clinical features, diagnostic modalities and therapeutic options for this increasingly recognised phenomenon.

Alpha interferon treatment in myasthenia gravis: effects on natural killer cell activity

The efficacy of recombinant interferon-alpha (rIFN alpha), on natural killer (NK) cell cytotoxic activity, CD3+, CD4+, CD8+, CD56+, HLA-DR+ lymphocyte counts, anti-acetylcholine receptor antibody (AChR Ab) levels, single fibre electromyography findings (SFEMG) and clinical course were evaluated in patients with myasthenia gravis (MG). During the IFN alpha treatment (3 mu, subcutaneous, 3 times a week), NK cell cytotoxicity and CD4+/8+ ratio increased, NK cell count remarkably decreased, and no significant clinical or SFEMG changes were observed. This preliminary open study in MG patients has demonstrated enhanced NK activity per unit NK cell after IFN alpha therapy. Although lymphocyte phenotypes and NK function approached normal levels during therapy, a higher dose of IFN alpha may be required for a significant clinical response. It has been also concluded that 6 months of IFN alpha therapy seems to be safe in MG, though in patients with malignancy, IFN alpha may cause increased autoimmunity, AChR positivity and MG.

Cytokine-induced autoimmune disorders

Cytokines are now commonly used in the treatment of many conditions, especially cancer, haematological malignancies and chronic viral hepatitis. With some of these cytokines, clinical induction and/or exacerbation of autoimmune manifestations have been observed. This has been the case with interferon-alpha and interferon-gamma, interleukin-2 and some colony-stimulating factors. All known biological and clinical autoimmune features have been observed but thyroid abnormalities have been particularly frequent. Some of these manifestations appear to be related to the effect of these exogenous cytokines on the T helper cell (TH) 1/TH2-cytokine balance and the regulatory properties of these cells. Patients with a history of underlying autoimmune disease or baseline serological abnormalities should be monitored for autoimmunity when treated with certain TH1 or TH2-inducing cytokines.