Since low-affinity immunoglobulin gamma Fc region receptor IV, Fcgr4, has been reported to be upregulated in leishmaniasis-infected mice, and ligation of FCGR4 by antigen-IgE(b) immune complexes could promote macrophage-mediated phagocytosis, antigen presentation to T cells, and proinflammatory cytokine production [46], it has also been used as a potential diagnostic marker for cutaneous leishmaniasis [47]. The gene discussed is IGHE; the disease is leishmaniasis.