Understanding Immune Thrombocytopenia: Looking Out of the Box

Abstract

The pathogenesis of immune thrombocytopenia (ITP) is increasingly being elucidated, and its etiology is becoming more frequently identified, leading to a diagnostic shift from primary to secondary ITP. The overlap between autoimmunity, immunodeficiency, and cancer is evident, implying more interdisciplinarity in daily care. This mini-review is based on an expert meeting on ITP organized by the Intercontinental Cooperative ITP Study Group and presents the challenges of hematologists in understanding and investigating "out of the box" concepts associated with ITP.

Keywords: ITP syndrome; autoimmunity; cancer; immune thrombocytopenia; immunodeficiency; overlap syndromes; secondary ITP.

Figure 1

Dysregulation of immune balance. Immune balance can be disturbed on two levels: immune tolerance (on the right) or immune activation (on the left). Onset of a disease can be simplified by the shift in the balance on one side or the other (cancer in orange vs. autoimmunity in yellow) or on the vertical axis, represented by the dotted lines (immunodeficiency in green vs. complex immune dysregulation in gray).

Figure 2

Immunodeficiency, autoimmunity, and cancer: “The immune trilogy.” Disturbance of the immune system can have multiple outcomes, such as cancer, autoimmunity or immune deficiency. The complexity and linkage between each of them can be demonstrated as “the immune trilogy.” Here are presented some examples of disease overlap. CLL, chronic lymphocytic leukemia; CVID, common variable immunodeficiency; ITP, immune thrombocytopenia; PID, primary immunodeficiency.