The cellular immunobiology associated with fetal and neonatal alloimmune thrombocytopenia.

Fetal and neonatal alloimmune thrombocytopenia (FNAIT) is caused by maternal antibodies that cross the placenta in connection with pregnancy and destroy fetal platelets. Recently, maternal T cell responses associated with FNAIT have been studied at the clonal level. These T cell clones recognize an integrin ß3 epitope, which is anchored to the HLA-DRB3∗0101-encoded MHC molecule DR52a. The same MHC allele is strongly associated with FNAIT. As the production of pathological antibodies reactive with fetal platelets is likely dependent on these T cell responses, there exists a potential for preventing FNAIT by targeting these T cells.