In autoimmune disease, Fc receptors (FcRs) form the interface between immune effector cells and their antibody-coated targets, and as such are attractive targets for immunomodulatory therapy. In this issue of the JCI, two highly novel studies of Fc-FcR interactions provide new insights into the role of FcRs in immune thrombocytopenia. Asahi et al. utilized a comprehensive platform of immunologi...

The diagnosis of idiopathic immune thrombocytopenia remains a clinical diagnosis based on the exclusion of other causes of immune and nonimmune thrombocytopenia. Measurement of platelet-associated Ig (PAIg), while sensitive, is nonspecific for the diagnosis of immune thrombocytopenia. Published experience of antigen capture assays (including monoclonal antibody immobilization of platelet antige...

We develop a mathematical model of platelet, megakaryocyte, and thrombopoietin dynamics in humans. We show that there is a single stationary solution that can undergo a Hopf bifurcation, and use this information to investigate both normal and pathological platelet production, specifically cyclic thrombocytopenia. Carefully estimating model parameters from laboratory and clinical data, we then a...

In a study of the clinical and immunogenetic profiles of 17 patients with rheumatoid arthritis and thrombocytopenia (platelet count less than 150 000/mm3 (150 x 10(9)/l)) due to gold therapy two clinical patterns were distinguished without knowledge of HLA type: group I, an early precipitous thrombocytopenia (10 patients), and group II, a less dramatic fluctuant fall (seven patients). In group ...

Despite its apparently strict granulocytotropism, thrombocytopenia is a consistent hallmark of infection with the agent of human granulocytic ehrlichiosis (HGE), regardless of host species. Laboratory mice are valuable models of HGE agent infection kinetics and immunity, but initial studies of HGE infection in mouse models have failed to demonstrate thrombocytopenia. More thorough analysis of p...

BACKGROUND Trastuzumab is a humanized, monoclonal antibody that interferes with the HER2/neu receptor and binds selectively to the HERB2 protein which causes uncontrolled proliferation of malignant breast cells. CASE REPORT We report a case of severe thrombocytopenia related to trastuzumab administration. Three days after the first dose of single-agent trastuzumab, the patient was admitted to...

Studies are reported pertaining to platelet-associated IgG (PAIgG) and IgM (PAIgM) in patients with thrombocytopenias considered possibly immune-mediated on clinical grounds. Approximately 14 percent of all patients with these disorders had elevated PAIgM but normal levels of PAIgG. Of patients with classic autoimmune thrombocytopenia (ITP), there was a trend toward more frequently normal level...

Patients presenting with bone marrow fibrosis not accompanied by well-established autoimmune diseases, such as systemic lupus erythematosus, or malignant diseases, are considered to have primary autoimmune myelofibrosis (AIMF). Primary AIMF has been reported to follow a benign course and responds well to treatment with immunosuppressive agents. Immune thrombocytopenia (ITP) is also an autoimmun...