2021 Volume 67 Issue 1 Pages 1-8
Background: Detection of IgG antibodies using an indirect anti-globulin analysis is generally useful as a clinical laboratory examination. IgG has four subclasses, of which IgG1 and IgG3 have high complement binding activities which are reported to be frequently involved in hemolytic reactions. The purpose of this study was to evaluate the clinical significance of IgG subclasses regarding the respective alloantibodies or autoantibodies.
Methods: We measured fluorescence intensities by flow cytometry to investigate titers of erythrocyte-bound IgG subclasses in patients (n = 185) with anti-D, anti-E, anti-c, anti-e, anti-Fyb, anti-Dia, anti-Jka, anti-Jkb and warm autoantibodies. Further, we performed monocyte monolayer assay (MMA) in about 30 of these cases to confirm clinical significance.
Results: The IgG subclasses IgG1 and IgG3 were common as a single antibody, while IgG1+IgG3 was common as multiple antibodies. In patients with anti-E antibody, single antibody with IgG1 or multiple antibodies with IgG1+IgG3, respectively, were common. High levels of cell-bound IgG3 showed a high phagocytic ratio in MMA.
Conclusions: IgG3 and IgG1+IgG3 alloantibodies in patients with anti-E antibody warrant further investigation.
