Hematologic manifestations of connective autoimmune diseases

Autoimmune connective tissue diseases (ACTDs) constitute a heterogeneous group of chronic immune-mediated inflammatory disorders, primarily affecting connective tissues and usually characterized by multisystem involvement with variable and frequently overlapping clinical manifestations. Abnormal immune regulation patterns and persistent inflammation are ACTD hallmarks. In such a context, autoimmunity/inflammation-associated cellular and molecular networks drive a complex of reactions that may involve hemopoietic tissue and peripheral blood cells. Hematologic abnormalities affecting one or more cellular lineages are frequent manifestations of ACTDs, and may represent an important prognostic factor, reflecting the rate of activation of autoimmune/inflammatory processes. Moreover, an increased frequency of hematologic malignancies, mainly lymphoproliferative disorders, has been observed in ACTDs, such as Sjögren's syndrome, systemic lupus erythematosus, rheumatoid arthritis, and polymyositis/dermatomyositis. A proliferative drive likely constitutes the link between chronic immune activation/dysregulation and malignant transformation, creating an increased risk for genetic aberrations that may lead to uncontrolled clonal proliferation. Revealing the nature of lymphomagenesis in relation to autoimmunity/inflammation will allow the identification of subjects at risk in order to select the appropriate diagnostic and therapeutic options. In this paper, the main hematologic manifestations of adulthood ACTDs are reviewed and discussed.