An anti-Jk3 was identified in the serum of a healthy 35-year-old female donor who had not been transfused. The proposita (Mrs. Suzu.) has two children and a histry of three stillbirths. The serum of Mrs. Suzu. was reacted with all the cells tested except three Jk (a- b-) cells by anti-globulin test, but it very weakly reacted with the dominant Jk (a- b-) cells. The antibody was only active in the antiglobulin test phase and was of the IgG1 subclass. Proposita's red cells were resistant to urea lysis using the Groupamatic-360 GMP III system. Her red cells failed to react either with anti-Jka, anti-Jkb or anti-Jk3 as expected. These negative reactions were reconfirmed by absorption-elution tests.
The anti-Jk3 was absorbed by cells from the lymphocytes and granulocytes layer, but both the anti-Jka and anti-Jkb were not.
