RARE INSTANCE OF ANTI-LAN ANTIBODY IN A MAN LACKING LAN ANTIGEN

Lan is a frequently occurring red blood cell antigen observed in over 99.9% of the population. We describe herein a 42-year-old Japanese man who developed anti-Lan antibodies after transfusion of three units of packed red blood cells. His red cells and those from one of his four brothers were found to be Lan-negative, whereas those from the rest of his family, including his parents and his two children, were Lan-positive. His parents were first cousins. To evaluate the frequency of Lan antigen in Japanese living in Ibaraki Prefecture, we screened red blood cells from 4100 unrelated individuals by antiglobulin testing of the patient's serum. No other persons lacking Lan antigen were found.