No abstract

Background and objectives: The ABO antibody (Ab) titration tests are used in monitoring in ABO-incompatible (ABOi) solid organ transplantation (SOT). However, currently developed ABO Ab tests show Ab binding reactions. This study attempted to measure ABO Ab level using complement-dependent cytotoxicity (CDC). Materials and methods: We studied 93 blood group O serum samples from patients who underwent ABOi SOT from January 2019 to May 2021. Patients’ sera were incubated with A1 or B cells and added to a human complement solution. Supernatants were collected after centrifugation, and free hemoglobin (Hb) was measured by spectrophotometry. We converted plasma Hb value to hemolysis (%), which were compared with ABO Ab titer. Results: We found a mild correlation between hemolysis and ABO Ab titers. In simple regression analysis, the correlation coefficients were within 0.3660–0.4968 (p < 0.0001) before transplantation. In multiple linear regression analysis, anti-A hemolysis (%) was higher in immunoglobulin M (IgM) (β = 12.9) than in immunoglobulin G (IgG) (β = −3.4) (R2 = 0.5216). Anti-B hemolysis was higher in IgM (β = 8.7) than in IgG (β = 0.0) (R2 = 0.5114). There was a large variation in hemolysis within the same Ab titer. Conclusions: CDC can be used in a new trial for ABO Ab measurement. Furthermore, IgM rather than IgG seems to play a significant role in vivo activity, consistent with previous knowledge. Thus, this study may help in the development of the ABO Ab titration supplement test for post-transplant treatment policy establishment and pre-transplant desensitization.

No abstract

Background: Detection of anti-Kidd antibody is important because of its clinical significance. If detection is difficult due to weak serological reactivity or dosage effect, use of an enzyme method could be helpful. However, despite use of an enzyme method, we still observed weak reactivity of anti-Kidd antibody. Methods: All identified anti-Kidd antibody cases from Jan 2012 to Aug 2015 in Asan Medical Center were reviewed. Antibody identification test was performed using the column agglutination technique using Bio-Rad ID-DiaPanel with LISS/Coombs card, Bio-Rad ID-DiaPanel-P with NaCl/Enzyme card, and ID-DiaPanel-P with LISS/Coombs card. The test results were compared. Results: Sixty cases of anti-JK a or anti-JK b were detected and tested by enzyme method. Among them, 34 (56.6%) cases showed strengthened reactivity using the ID-DiaPanel-P with NaCl/Enzyme card method. However, 26 (43.4%) cases showed weakened reactivity. Of these, 13 cases that could be tested by an additional method using ID-DiaPanel-P with LISS/Coombs card containing anti-IgG and anti-C3d showed successfully strengthened reactivity. Conclusion: The reactivity of anti-Kidd antibodies that was not strengthened using ID-DiaPanel-P with NaCl/Enzyme card method could be successfully strengthened by use of the ID-DiaPanel-P with LISS/Coombs card. (Korean J Blood Transfus 2016;27:31-37)