IGHE and systemic lupus erythematosus: Interestingly, CD23 is prone to shedding by disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) resulting in various soluble forms (monomeric or trimeric with varying sizes), all of which are capable to bind IgE (214, 217) and are found in autoimmune diseases like SLE where auto-IgE has been described (218).