IL4 and kidney disorder: This experimental study was performed in vitro on cultured B lymphocytes from children with IgAN, treated or not with interlukin-4 (IL-4) or 5-aza-2’-deoxycytidine (5-Aza-dC, AZA); the IgAN lymphocytes were compared to lymphocytes from children with other renal diseases or from healthy children (S1 Fig.).