KEL基因c.715G＞T突变致罕见K0表型2例OA

Objective To investigate the serological identification and blood group gene sequencing analysis of two rare cases of K0 phenotype producing high-frequency antigen antibodies(anti-Ku),and to study the serological interrelationship between K0 cells and the high-frequency antigen antibody anti-KL.Methods Serological methods were used to identify the antigen phenotypes of the ABO,Rh,and Kell blood group systems and to screen for and identify unexpected antibodies in the two patients.The characteristics of the unexpected antibodies were verified by the indirect antiglobulin test(IAT)using papain or dithiothreitol(DTT)-treated screening cells.The titer of anti-Ku was determined via the tube method using DTT-treated plasma.The Kell blood group genotype was determined by gene sequencing.The distinctive antigenicity of K0 cells was validated through their reactivity with anti-KL in IAT,and absorption-elution techniques were employed to corroborate the type of anti-KL.Results Serological findings:Case 1 was blood group O,CCDee;Case 2 was blood group A,CCDee.Both cases exhibited the Kell phenotype:K-k-,Kp(a-b-).High-frequency antigen antibodies were detected in the plas-ma of both patients.The reactivity of these antibodies was slightly enhanced with papain-treated screening cells but became negative with DTT-treated cells.The anti-Ku(IgG)titer for Case 1 was 64.For Case 2,the anti-Ku(IgM)titer was＜1,and the anti-Ku(IgG)titer was 32.Gene sequencing revealed that both cases harbored a homozygous c.715G＞T mutation in the KEL gene,corresponding to the genotype KEL02N.24,consistent with the rare K0 phenotype.The unique high ex-pression of the Kx antigen on K0 cells was confirmed through the antibody characteristics of anti-KL.Absorption-elution techniques demonstrated that K0 cells could separate anti-Km and anti-Kx,thereby supporting the classification of anti-KL.Conclusion Serological and molecular biological assays identified both patients as having the rare Kell-null(K0)pheno-type.If such rare blood types go undetected in transfusion medicine,the administration of standard blood products can read-ily induce the production of high-frequency antigen antibodies such as anti-Ku,potentially leading to a transfusion crisis due to the subsequent difficulty in finding compatible blood.The serological relationship between K0 cells and anti-KL clarified the characteristic high expression of the Kx antigen on K0 phenotype erythrocytes and concurrently supported the typological features of the rare high-frequency antibody anti-KL.This represents the first such verified report in China.