Stanford Healthcare Sunnyvale, California, United States
Background/Case Studies: The recognition of rare blood group antibodies is crucial in transfusion medicine, particularly in patients with unique phenotypes such as Jk(a-b-). The Anti-Jk3 antibody, first described in 1959 by Pinkerton et al., is associated with the Jk(a-b-) phenotype, which results from the homozygous inheritance of silent alleles of the JK gene located on chromosome 18q11. This null phenotype is relatively rare in the general population but more common among individuals of Polynesian ancestry.
Study
Design/Methods: A 90-year-old Asian female presented to the emergency department with shortness of breath, four days post-carotid endarterectomy for a cerebrovascular accident. She reported worsening respiratory symptoms and generalized weakness but denied fever or other significant complaints. A type and screen sample sent to the transfusion service showed pan-reactivity across all tested cells. This case study discusses the identification of Anti-Jk3 in this patient, emphasizing the importance of thorough serological workup in ensuring patient safety and effective management.
Antibody detection was performed using solid-phase techniques, followed by a tube method with polyethylene glycol (PEG) for enhanced sensitivity. The initial solid-phase test indicated pan-reactivity, leading to the use of the 8-cell panel tube technique, which yielded similar results except for a weakly positive autologous control. A direct antiglobulin test (DAT) was weakly reactive with IgG only, and no antibodies were detected upon elution.
Further analysis confirmed the patient’s Jk(a-b-) phenotype, prompting the use of rare in-house Anti-Jk3 antisera and frozen Jk(a-b-) red cells, which ultimately confirmed the presence of Anti-Jk3. PEG allo-adsorption was subsequently performed, ruling out other clinically significant antibodies.
Results/Findings: NA Conclusions: This case underscores the importance of a meticulous serological workup in identifying rare antibodies like Anti-Jk3, particularly in patients with uncommon blood group phenotypes. The successful identification of Anti-Jk3 not only enhances patient safety during transfusions but also highlights the need for specialized resources in pathology and laboratory medicine. Furthermore, it is essential to recruit donors who are Jk3-negative to ensure an adequate supply of compatible blood products for patients with this rare antibody. This case serves as a reminder of the critical role that laboratory professionals play in managing complex transfusion scenarios and ensuring optimal patient outcomes.
