Rheumatoid arthritis: 'melting pot' of T helper subsets

Rheumatoid arthritis (RA) is an autoimmune disorder that affects joints associated with inflammation leading to poor quality of life. The phenotype of RA is distinct from osteoarthritis (OA), the degenerative joint disorder. The annual incidence of RA is approximately 4 in 10,000 individuals. Studies suggest dysregulated T cell activation in the initiation and progression of RA. Distinct RA-associated allelic variants encode molecules involved in T-cell activation pathways. Additionally, RA is also associated with aberrant regulation and function of T helper cells. The interplay of distinct T helper cell subsets adds complexity to the regulation of RA. In this review we have aimed to understand the currently known biology of different Th subsets in the context of an autoimmune disease like rheumatoid arthritis and find potential therapeutic approaches to tackle the disease through modulation of responsible T cells.