Transfusion medicine
Red blood cell antigens
Kidd system
Editorial Board Member: Kyle Annen, D.O.
Deputy Editor-in-Chief: Patricia Tsang, M.D., M.B.A.
Last author update: 13 January 2022
Last staff update: 13 January 2022
Copyright: 2021-2023, PathologyOutlines.com, Inc.
PubMed Search: Transfusion medicine Kidd system
Table of Contents
Definition / general | Essential features | Terminology | Antigens | Antibodies | Pathophysiology | Clinical features | Transmission | Laboratory | Case reports | Additional references | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Adkins BD, Booth GS. Kidd system. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/transfusionmedkiddsystem.html. Accessed June 1st, 2023.
Definition / general
- Antigenic
- Antibodies clinically significant
Essential features
- Most Kidd antigens are widely expressed in the donor population
- Antibodies can cause hemolysis and hemolytic disease of the fetus and newborn (HDFN)
- Kidd antibodies often drop below the level of detection and are commonly implicated in delayed hemolytic transfusion reactions
- Kidd antibodies are often capable of activating complement and can cause intravascular hemolysis
Terminology
- Kidd a or Jka
- Kidd b or Jkb
Antigens
- Type: peptide
- 3 significant antigens: Jka, Jkb and Jk3 (AABB: Technical Manual, 20th Edition, 2020)
- Jka and Jkb are frequently expressed in most ethnic populations (AABB: Technical Manual, 20th Edition, 2020)
- Individuals negative for both antigens Jk(a-b-) are infrequent except in Polynesian and Finnish populations but can form antibodies against Jk3, a high incidence antigen in all individuals with any Jk positivity (Transfus Med Rev 2017;31:165)
- Kidd glycoprotein is encoded by the HUT11 / UT-B / JK (SLC14A1) gene encoded at 18q12-q21 (Transfus Med Rev 2017;31:165)
- Kidd glycopeptide functions as a transmembrane urea transporter on red cells, which helps to maintain cellular osmotic stability; also helps the kidney concentrate urine (AABB: Technical Manual, 20th Edition, 2020)
| Jk(a+b-) | Jk(a+b+) | Jk(a-b+) | Jk(a-b-) | |
| White | ||||
| Black (U.S.) | ||||
| Asian |
Antibodies
- Majority IgG, fewer IgM (AABB: Technical Manual, 20th Edition, 2020)
- Occur with exposure to products containing incompatible blood or pregnancy
- Antibodies tend to decrease over time; may become undetectable by blood bank methodology, posing a risk of transfusion reaction
- Can cause hemolytic reactions and hemolytic disease of the fetus and newborn
- Majority IgG1 or IgG3 and can fix complement (AABB: Technical Manual, 20th Edition, 2020)
- Antibodies are enhanced when using enzyme treated red cells
Pathophysiology
- Antibodies tend to decrease in level over time and then rapidly increase with subsequent exposure
- Plasma cell memory is called an anamnestic response
- Decrease in antibody level over time to a potentially undetectable level is known as evanescence
- Antibodies formed tend to be IgG1 or IgG2, which are better at fixing complement; this causes intravascular hemolysis clinically
- Reference: AABB: Technical Manual, 20th Edition, 2020
Clinical features
- Kidd antibodies often drop below the level of detection and are commonly implicated in delayed hemolytic transfusion reactions
- Kidd antibodies are often capable of activating complement and can cause intravascular hemolysis
- Reference: AABB: Technical Manual, 20th Edition, 2020
Transmission
- Exposure to Kidd antigens secondary to pregnancy or transfusion
Laboratory
- 2M urea testing can be used to distinguish Kidd positive versus Kidd null individuals; Kidd positive cells will lyse with a rapid influx of urea while Kidd null cells will remain intact
- Conversely, 5M urea is the concentration used for determining factor XIII deficiency
- Resistant to proteolytic enzymes, such as papain and ficin
- Reference: AABB: Technical Manual, 20th Edition, 2020
Case reports
- Newborn girl with hemolytic disease caused by anti-Jkb antibodies (Indian J Hematol Blood Transfus 2014;30:135)
- 32 year old woman with sickle cell disease developed hyperhemolysis secondary to multiple antibodies including Jkb (Indian J Hematol Blood Transfus 2016;32:251)
- 73 year old man with Jk3 sensitization after cardiac surgery (Kyobu Geka 2017;70:457)
- Case series of Jk3 antibody positive mothers (Transfusion 2018;58:1157)
- Novel Jk allele associated with Jk3 antibody production (Transfusion 2018;58:1078)
Additional references
Board review style question #1
A patient has a negative antibody screen and receives a red blood cell transfusion for symptomatic anemia. 2 days later, the patient develops hematuria and is found to have a positive direct antiglobulin test (DAT [IgG and C3]). A screen demonstrates a previously unidentified Jkb antibody. What antibody characteristic likely contributed to this delayed hemolytic transfusion reaction?
- Dosage
- Dithiothreitol treated red cells
- Enzyme treated red cells
- Evanescence
Board review style answer #1
Board review style question #2
What molarity of urea is used to determine if individuals are Jk(a-b-) and to evaluate for factor XIII deficiency, respectively?
- 1M / 2M
- 2M / 2M
- 2M / 5M
- 5M / 5M
Board review style answer #2
