Lan is a high prevalence red blood cell
antigen present in the majority of the populations that belong to the Lan (Langereis)
blood group system. Anti-Lan antibody is an
immunoglobulin G (
IgG) antibody that is known to cause delayed
hemolytic transfusion reactions in adults as well as hemolytic disease in fetuses and newborns, however with variable clinical significance ranging from mild to severe. We present a 58-year-old woman with diffuse
abdominal pain and a large
gastric ulcer causing
gastric outlet obstruction. She underwent antrectomy and
Billroth I reconstruction surgery without complications. The patient's
hemoglobin upon presentation was 10g/dL and dropped acutely post-operatively to 6.4 g/dL requiring
blood transfusion. The patient developed acute respiratory distress within minutes of starting a packed red blood cell (pRBC) transfusion, requiring discontinuation. Laboratory testing demonstrated pan-reactivity with additional reference testing demonstrating an anti-Lan antibody. The rarity of Lan negative pRBC units is a challenge in managing such patients requiring
blood transfusions. Autologous blood donation or donation by a compatible family member is another option to consider in these rare cases.