In one case report, the authors (after previously using bortezomib to treat a patient with pure red‐cell aplasia stemming from an ABO‐mismatched stem cell transplantation) employed the same treatment in a patient with Cold Agglutinin Disease (CAD) secondary to IgM κ monoclonal gammopathy.18 The gene discussed is CD40LG; the disease is cold agglutinin disease.