Korean J Blood Transfus.  2024 Aug;35(2):121-125. 10.17945/kjbt.2024.35.2.121.

An Opinion on the Cause of Anti-K Found in Koreans

• Lee JK
• Seo J
• Cho D

• KMID: 2558985
• DOI: http://doi.org/10.17945/kjbt.2024.35.2.121

Abstract

The K antigen, one of the 38 immunogenic antigens in the Kell blood group system, can cause severe hemolytic transfusion reactions (HTR) and hemolytic disease of the fetus and newborn (HDFN). The frequency of incidence of the K antigen varies by race (9.02% of Western populations are K＋ compared to 0.0% in Koreans), and the incidence and causes of anti-K vary accordingly. Anti-K have occasionally been detected in antibody screening/identification tests, but no hemolytic transfusion reactions have been reported in Korea so far. We conducted a retrospective review of nine cases of anti-K identified at the Samsung Medical Center over the past five years, most of which involved Koreans. No clear causes, such as the transfusion of K antigen-positive donor blood, pregnancy, or infections known to trigger anti-K, were identified. It has been speculated that the increased immigration of people of different races with the K antigen might be a reason for the anti-K formation. However, given the frequency of K＋ reported in recent literature and observed in our study, it is suggested that these “unknown causes” may be more common than previously believed. Hence, prospective studies are warranted to identify these causes more accurately.

Keyword

Kell blood group; Anti-K antibody; Korean population