Benign High Prevalence Antibody Yta

Abstract

Abstract Introduction/Objective The Yt system, also known as the Cartwright system, discovered in 1964, consists of five antigens encoded by the ACHE gene on chromosome 7. Yta and Ytb are antithetical antigens on the GPI – linked red cell glycoprotein, acetylcholinesterase (AChE). About 8-10% of individuals of European ancestry are Yt(b+); Yta is highly prevalent in all populations. The other three high-prevalence antigens, YTEG, YTLI, and YTOT, were added to this system in 2018. Yta is not affected by trypsin but is destroyed by α-chymotrypsin treatment of reagent red cells. Yta and Ytb are sensitive to disulfide bond-reducing agents 2-aminoethylisothiouronium bromide (AET) and dithiothreitol (DTT). Yt antibodies are mostly IgG and require Indirect Antiglobulin Test (IAT) for detection. Yt antibodies are not clinically significant, although anti-Yta may cause accelerated destruction of Yt(a+) transfused red cells. Monocyte Monolayer Assay (MMA) is often used to determine whether the anti-Yta is predicted to cause destruction of transfused Yt(a+) red cells. Methods/Case Report A 50 year old female of Hispanic/Latino descent with a BRCA2 mutationand a history of scoliosis and severe migraineswas admitted for robotic-assisted bilateral salpingo-oophorectomy, cystoscopy, and dilation and curettage. A type and screen was ordered preoperatively, and her antibody screen was positive. In her profile, the origin of anti-Yta was identified from an outside facility since 2008, but written documentation of anti-Yta identification could not be located. On antibody identification, the patient’s plasma was reactive with all cells (1+ AHG in PEG) except the auto control. Rare frozen anti-Yta antisera were used for phenotyping the patient for Yta and she was found to be Yta negative. Yta antigens are sensitive or weakened by DTT, so DTT-treated panel screen cells were used to rule out all clinically significant alloantibodies except for the Kell system. Anti-K and anti-k were ruled out by testing the patient’s plasma against SCARF (Serum, Cells, and Rare Fluid Exchange) Yta negative with homozygous K positive and homozygous k positive cells. Anti-Yta was reconfirmed at our facility. Results (if a Case Study enter NA) NA Conclusion Yta-negative blood is so rare that anti-Yta reacts > 99.8% of most populations. In some cases, autologous transfusion may be recommended for a patient. However, anti-Yta is often benign, and antigen-negative blood may not need to be transfused. The patient had uncomplicated procedures, and blood transfusion was not indicated at that time.