CD40LG and Cataplexy: However, the HLA-DQB1*0602 allele is more present in patients with narcolepsy and cataplexy, with a decrease in the population of hypocretinergic cells directly to an immunological mechanism.17, 26Clinical improvement after using immunoglobulin and prednisone strengthens this hypothesis.27, 28The association between narcolepsy and the TCR α locus, as well as the decrease in the concentration of soluble CD40 ligand (CD40L) in patients with narcolepsy, are strong indications of an autoimmune mechanism.21, 29