SYK and autoimmune hemolytic anemia: The targets of new therapies in AIHA are mainly the B lymphocytes, T lymphocytes and the complement cascade, but they also include the spleen tyrosine kinase (SYK) on macrophages and the neonatal crystallizable fragment of the receptor (FcRn) present on many cells, including endothelial cells and macrophages (Fig. 5).