While the IL-4-stimulated isotype effector function in the mouse and human cannot be directly correlated, elevated levels of IgE have shown to be a prognostic marker of poor outcome for KSHV non-Hodgkin lymphomas (Uldrick et al., 2014) and associated with the extent of KS lesion development (Barbachano-Guerrero et al., 2017). This evidence concerns the gene IGHE and Kaposi's sarcoma.