We have shown previously that basophils are involved in the development of lupus nephritis in a spontaneous mouse model of SLE (Lyn−/− mice), in the pristane-induced lupus-like nephritis model, and in a cohort of 42 patients by accumulating in SLO to support autoreactive T and B cells through an IgE and IL-4-dependent pathway4,24. Here, IL4 is linked to systemic lupus erythematosus.