An example of anti-K1 found in a Japanese patient with occipitalcraniomenigiomata, aged 19 years, is reported. His red cells had not K1 antigen. The patient had no history of prior blood transfusion, but he received twelve units of K1 negative and compatible red blood cells at the time of surgery in July 1982. No clinical and haematological signs of red cell destruction were noted. Unexpected antibodies were not detectable by routine pretransfusion screening.
However, in September 1982, his serum was found to contain an IgG antibody with anti-K (K1) specificity; the titer of which was 16 to 32 with K:1 and 8 to 16 with K:1, 2 cell samples by the indirect antiglobulin test using anti-IgG.
His red cells gave a doubtful direct antiglobulin test using polyspecific antiglobulin and anti-C3, but not anti-IgG. Anti-K1 specificity was demonstrated in an eluate from his red blood cells.
The antibody stimulation of the anti-K1 remains unknown.
