Myasthenia gravis is a B-cell-mediated autoimmune disorders causing muscle weakness due to defective synaptic transmission at the neuromuscular junction caused by autoantibodies to acetylcholine receptors in (∼85%), muscle specific kinase in 6% and low-density lipoprotein receptor-related protein 4.The detection of these autoantibodies is very important not only in the diagnosis, but also for the stratification of Myasthenia Gravis patients into respective subgroups. These groups can differ in clinical manifestations, prognosis and response to therapies which become relevant for the development of antigen-specific therapies, targeting only the specific autoantibodies involved in the autoimmune response.

Follicular T cells play a vital role during autoimmune disorders. The enhanced number or activation of these cells results in hyperproliferation of autoreactive B cells and overproduction of antibodies. Interleukin-37 is a newly identified immune-suppressive factor. It acts as an inhibitor of inflammation and plays an important regulatory role in both innate and adaptive immune responses. In Myasthenia Gravis, Cluster of differentiation 4+ T cell is the dominant cellular source for Interleukin-37 production directed to T follicular helper and B cells .It represses cell proliferation and secretion of autoantibody indicating that Interleukin-37 is a critical regulatory factor. The immunosuppressive features of Interleukin 37 contributing to autoimmune diseases are important and still poorly investigated. For this reason, the present study is designed to detect the level of expression of Interleukin 37 in Myasthenia Gravis patients and its correlation with autoantibodies serum levels and disease severity.

Inclusion Criteria:

1. Clinical Diagnosis of Myasthenia Gravis.
2. Willingness to sample collection.

Exclusion Criteria:

1. History of chronic psychiatric or neurological disorder other than Myasthenia Gravis that can produce weakness or fatigue.
2. Severe systemic illness affecting life-expectancy ( chronic liver or kidney diseases).
3. History of autoimmune diseases, connective tissue diseases, , or genetic diseases.
4. Patients on large dosage of immune-suppressive treatment or Intravenous immunoglobulin in the recent 3 months.

The estimated minimum required sample size is 84 cases (42 case in each group). sample size was calculated using G*power software 3.1.9.7. As this study aims to detect the large difference between the the group of Myasthenia Gravis patients relative to the healthy controls, so the calculation based on determining the large effect size.

Main statistical test is two tailed t-test to detect difference between two groups .

Effect size = 0.8 Alpha = 0.05 Power = 0.95 Allocation ratio = 1