Two cases of rare K
phenotype caused by the KEL c.715G>T mutation
10.13303/j.cjbt.issn.1004-549x.2026.04.016
- VernacularTitle:KEL基因c.715G>T突变致罕见K
表型2例
- Author:
Jing LI
1
;
Jing ZHANG
2
;
Zhixia CHENG
1
;
Jian DU
1
;
Xiaoling ZHANG
1
Author Information
1. Central Blood Stationof Baoding, Baoding 071000, China
2. Hebei Blood Center, Shijiazhuang 050071, China
- Publication Type:Journal Article
- Keywords:
K0 phenotype;
high frequency antigen antibody;
anti-Ku;
anti-KL;
gene sequencing
- From:
Chinese Journal of Blood Transfusion
2026;39(4):526-533
- CountryChina
- Language:Chinese
-
Abstract:
Objective: To investigate the serological identification and blood group gene sequencing analysis of two rare cases of K
phenotype producing high-frequency antigen antibodies (anti-Ku), and to study the serological interrelationship between K
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 K
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 plasma 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 K
phenotype. The unique high expression of the Kx antigen on K
cells was confirmed through the antibody characteristics of anti-KL. Absorption-elution techniques demonstrated that K
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 (K
) phenotype. If such rare blood types go undetected in transfusion medicine, the administration of standard blood products can readily 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 K
cells and anti-KL clarified the characteristic high expression of the Kx antigen on K
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.
