Analysis of transmembrane signalling and T cell defects associated with idiopathic thrombocytopenic purpura (ITP).
Adult chronic idiopathic thrombocytopenic purpura (ITP) is an autoimmune disease characterized by production of autoreactive antibodies to platelet antigens. It is now becoming clear that autoantibody production, in general, is regulated by T helper (Th) cells. Several recent studies have examined potential defects in T cell function in this disease and have demonstrated that patients with ITP possess abnormal lymphocyte activation and Th1/Th2-mediated cytokine production. Although the underlying cause(s) of aberrant T cell function in this disease are not known, studies from other models of autoimmune disease indicate that defects in T cell transmembrane signalling can be causally linked to abnormal T cell activation and cytokine production. This review will present some of the major T cell signalling pathways and discuss how altered T cell signalling may be linked to autoimmunity with an emphasis on ITP. Recent preliminary findings of a potential defect in the signal transduction apparatus in lymphocytes from three patients with ITP will also be presented.
Lazarus
A H
AH
St Michael's Hospital, Department of Medicine, University of Toronto and The Canadian Red Cross Society Blood Services Toronto Centre, Ontario.
Joy
T
T
Crow
A R
AR
D015551:Autoimmunity / Q000276:immunology; D006801:Humans; D008213:Lymphocyte Activation; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000276:immunology*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology*
D011505:Protein-Tyrosine Kinases