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Allo-anti-M: Detection peaks around 2 years of age, but may be attenuated by red blood cell transfusion
Yoshiko Tamai1,2, Hitoshi Ohto1,3, Hiroyasu Yasuda1,4
1Japan Society of Blood Transfusion and Cell Therapy, Tokyo, Japan.
Background:
Anti-M is frequently observed as a naturally occurring antibody of little clinical significance. Naturally occurring anti-M is often found in children although the specific triggers of production, persistence, and evanescence of anti-M have yet to be elucidated.
Methods:
In a retrospective, multicenter, nationwide cohort survey conducted from 2001 to 2015, alloantibody screening was performed before and after transfusion in 18,944 recipients younger than 20 years. Recipients were categorized into six cohorts based on their age at transfusion; within and among these cohorts, allo-anti-M was analyzed in regard to its production, persistence, and evanescence.
Results:
In 44 patients, anti-M detected before and/or after transfusion was an age-related phenomenon, with a median age of 2 years and an interquartile range of 1-3 years; anti-M was most frequently detected in a cohort of children 1 to <5 years (0.77%, 31 of 4035). At least five patients were presumed to have concurrent infections. Among 1575 adolescents/young adults (15 to <20 years), no anti-M was detected. Of 29 patients with anti-M prior to transfusion, the antibody fell to undetectable levels in 17 recipients (89.5%, of whom at least 13 received only M-negative red cells) after anywhere from 5 days to 5.8 years; anti-M persisted in 2, and was not tested in 10. Only 15 recipients (0.08%) produced new anti-M after transfusion.
Conclusion:
Naturally occurring anti-M is a phenomenon of younger ages, predominantly between 1 and 3 years. After transfusion, it often falls to undetectable levels.
Insights
Naturally occurring anti-M antibodies are common in young children, typically between 1 and 3 years old. This antibody often becomes undetectable after blood transfusions, especially when M-negative red blood cells are used.
Area of Science:
- Immunology
- Transfusion Medicine
- Pediatrics
Background:
- Naturally occurring anti-M antibodies are generally considered of minor clinical importance.
- The exact triggers for anti-M production, its persistence, and disappearance in children remain unclear.
Purpose of the Study:
- To investigate the production, persistence, and evanescence of allo-anti-M in pediatric transfusion recipients.
- To analyze anti-M as an age-related phenomenon in children and adolescents.
Main Methods:
- A retrospective, multicenter, nationwide cohort survey was conducted from 2001 to 2015.
- Alloantibody screening was performed before and after transfusion in 18,944 recipients under 20 years of age.
- Recipients were stratified into six age-based cohorts to analyze anti-M characteristics.
Main Results:
- Anti-M was detected in 44 patients, primarily an age-related finding in children aged 1-3 years (median age 2 years).
- The highest detection rate (0.77%) was in children aged 1 to <5 years; no anti-M was found in adolescents aged 15 to <20 years.
- In patients with pre-transfusion anti-M, it became undetectable in 89.5% after transfusion, particularly with M-negative red cells; new anti-M production post-transfusion was rare (0.08%).
Conclusions:
- Naturally occurring anti-M is predominantly observed in younger children, especially between 1 and 3 years of age.
- Anti-M levels frequently decrease to undetectable levels following blood transfusions.
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