[Helper (TH1, TH2, TH17) and regulatory cells (Treg, TH3, NKT) in rheumatoid arthritis]

The immune response foreign antigens require a perfect coordination of cells that participate in its different phases. The objective of the response is the rapid destruction of the microorganisms with a minimum repercussion on self-cells and tissues. The regulation of this process is carried out fundamentally by T lymphocytes. There are two main types of coordinator cells: helper cells, what organize the initial immune response, and regulatory cells, what avoid immune attack against self and once the infection is controlled, disassemble the response. There are three types of helper cells which coordinate answers to intracellular parasites (TH1), helmints (TH2) and extracellular bacteria and fungi (TH17). The hyperfunction of TH17 cells is associated with diseases as reumatoid arthritis, due to the hypersecretion of the proinflammatory citoquine IL17. The condition of helper or regulatory cell is the current object of review. TH1, TH2 and TH17 cells have helper and also regulatory functions. In addition, regulatory T cells play an important role in the coordination of the first moments of the response to viral infection in a direct and indirect way, inducing differentiation of TH17 cells.