ICOS and myasthenia gravis: The expression levels of ICOS and PD-1, the corresponding ligands ICOSL and PD-L1 in B cells and their soluble forms (sICOS, sPD-1, sICOSL and sPDL-1) in the plasma of patients with MG revealed that ICOS/ICOSL and PD-1/PD-L1 are involved in the MG pathological process.