Infections and Immune Thrombocytopenic Purpura

Immune thrombocytopenic purpura (ITP) is an idiopathic disease defined by a low platelet count in the absence of other causes of thrombocytopenia such as malignancy, disseminated intravascular coagulation, or medication-induced thrombocytopenia. It is an (auto) immune-mediated disorder that affects both adults and children, although their clinical manifestations can be very different. The understanding of the pathophysiology of ITP has advanced dramatically since the first in vivo experiments were conducted by Dr. Harfington more than 50 years ago. Yet, much still needs to be learned about this interestingly diverse disease. Though it is known that auto-antibodies are made against platelet antigens, the initial trigger for antibody production is still unclear. Other issues that warrant further investigation include the mechanisms through which viruses initiate or maintain the disease process in ITP; this would have to take into account individual susceptibility factors (that is, genes). Other areas to be further elucidated include the role of inflammatory and anti-inflammatory cytokines, and mechanisms through which autoreactive immune cells escape negative selection by the developing immune system. The interaction between the immune system and infectious agents in the pathophysiology of ITP will remain a critical point of investigation.