“…[5][6][7][8][9][10][11][12][13][14] Examples of the most frequent comorbidities or secondary disorders that co-occur with MS include thyroid disease, rheumatoid arthritis, psoriasis, cardiovascular disorders, depression and anxiety, diabetes mellitus, chronic lung disease, and irritable bowel syndrome, among others. [4][5][6][8][9][10]14,15 The pathogenesis of these associations with MS is unclear at this time but may be linked to a genetic predisposi-tion, 5,16,17 the presence of a chronic inflammatory condition, 10 environmental factors, 18 and the use of disease-modifying therapy. 19 It has been postulated that CD4ϩ T-cells of the Th1 phenotype, CD8ϩ T-cells, and B-cells play a key role in focal and diffuse destruction of the CNS in patients with MS. 20 The immune deviation of CD 4ϩ T-cells into Th1 and Th2 phenotypes has been the subject of many immunologic and epidemiologic studies in MS. 21,22 In particular, it has been reported that Th1 responses associated with autoimmunity may be attenuated by a Th2 shift.…”