CONCLUSIONS: The convergence of CML, bullous pemphigoid, and PLA2R-positive MGN in CTLA-4 haploinsufficiency broadens the clinical phenotype and underscores the importance of considering inborn errors of immunity in young adults with refractory, multisystem autoimmunity and hematologic abnormalities. This evidence concerns the gene CTLA4 and idiopathic membranous glomerulonephritis.