BACKGROUND: A person exposed to foreign blood group antigens may produce an
tibodies. The persistence of antibodies varies among people and among antib
odies. A study was performed to investigate the persistence of clinically s
ignificant RBC alloantibodies over a period of 20 years.
STUDY DESIGN AND METHODS: A retrospective examination was performed of all
records of RBC antibodies in the transfusion laboratory computer database f
rom 1978 through 1997. Records of patients who underwent at least one antib
ody investigation after an antibody had been detected were studied. The stu
dy included all antibodies against the Rh, K, Fy, Jk, and MNs blood group s
ystems. An antibody was regarded as not persistent if, after previous detec
tion, the screening or panel studies became negative for the antibody under
study. Anti-D due to Rhlg administration was excluded.
RESULTS: An analysis was performed of 480 records consisting of 593 antibod
ies that fulfilled the criteria. Median antibody follow-up was 10 months (r
ange, 1-240). In 137 patients, 153 (26%) antibodies became undetectable ove
r the course of time. After initial negative screening investigations, 310
antibodies were formed. The antibodies that were still detectable had a med
ian follow-up of 7 months (range, 1-193). A patient's age, sex, and antibod
y specificity were of no influence on the length of time that antibodies we
re detectable. Antibodies detected with a more sensitive screening techniqu
e were less persistent (p = 0.0002). For 28 patients, detection of antibodi
es was highly irregular.
CONCLUSIONS: About 25 percent of all antibodies became undetectable over th
e course of time. The antibody screening technique used, rather than the an
tibody specificity, affected these results. To prevent delayed hemolytic tr
ansfusion reactions, precise antibody documentation is of great importance.