The Interleukin-7 Receptor Signaling Pathway and Its Perturbation in Immunodeficiency, Autoimmune Disease and Lymphoid Malignancy

Cell–cell signaling through a network of cytokine receptors is pivotal for normal immune development and function, with disruptions of these signaling pathways being implicated in a variety of immune cell diseases. Signaling via the interleukin-7 receptor (IL-7R) facilitates the development and homeostasis of various T-cell, B-cell and other immune-cell populations. This is reflected in the raft of mutants and variants of IL-7R components and downstream signaling molecules that have been identified in the context of immunodeficiencies, autoimmune disorders and lymphoid malignancies, but also through the use of pathway modulators as therapeutics. This review provides an overview of IL-7R biology, the role of mutations and variants affecting IL-7R signaling pathway components in the etiology of immune cell diseases and the specific therapies related to this pathway.