From the Research
The lowest titer of isohemagglutinin in humans is typically 1:4, though it can occasionally be lower, as supported by the most recent study 1 which analyzed the prognosis of ABO-incompatible kidney transplant patients undergoing desensitization.
Isohemagglutinin Titers
Isohemagglutinins are naturally occurring antibodies against blood group antigens that a person lacks, with anti-A and anti-B being the most clinically significant.
- These antibodies develop during early childhood through exposure to similar antigens in the environment, particularly from gut bacteria and certain foods.
- The titer varies considerably between individuals and can be influenced by factors such as age, pregnancy, and certain disease states.
- Newborns generally have no detectable isohemagglutinins, while elderly individuals often show declining titers.
Clinical Significance
In clinical settings, isohemagglutinin titers become important during ABO-incompatible organ transplantation and certain blood transfusions, where higher titers increase the risk of rejection or hemolytic reactions.
- Monitoring these titers is essential in these scenarios, with levels below 1:8 generally considered safer for transplantation procedures, as indicated by a study on ABO-incompatible kidney transplantation 2.
- A more recent study 1 found that baseline isoagglutinin titer does not influence the prognosis of ABO-incompatible patients after desensitization, but the number of sessions required to achieve a baseline titer <1:8 is higher for patients with higher initial titers.
Measurement and Reduction
Isohemagglutinin titers can be measured using automated solid-phase and hemagglutination-based analyzers, which yield comparable results to manual gel testing 3.
- Reduction of anti-A/B isoagglutinin titers in intravenous immunoglobulin products is feasible through implementation of anti-A donor screening, which may reduce the risk of hemolysis following therapy 4.