A family of JAK non-receptor tyrosine kinases regulates the transduction of signals from the cytokines and their receptors by activating STAT transcription factors and modulating STAT-dependent gene expression. Overactivation of the JAK/STAT pathway has been confirmed to occur in autoimmune diseases, where JAK kinanses are responsible for causing and maintaining inflammation. Developing a therapy based on JAK kinase inhibitors applies in many areas: oncology, by inhibiting excessive cell growth and proliferation (such as e.g. an JAK2 inhibitor in myeloproliferative syndromes and leukemias), immunology, by regulating the secretion of inflammatory cytokines (e.g. JAK1 inhibitor in chronic lung inflammation) and in transplantation due to an immunosuppressive effect (inhibition of JAK3 kinase). Inhibition of JAK kinases can therefore constitute treatment in a wide range of indications.