Serological studies of an SLE-associated antigen-antibody system discovered as a precipitation reaction in agarose gel: the HAKATA antigen-antibody system.

Current population studies indicate that the HAKATA antigen is one of the normal plasma proteins not yet completely characterized. The frequency of Japanese donor, patients and Swedish patients was 100%, 99.99% and 99.98%, respectively. Anti-HAKATA antibody production was found in three patients, all with systemic lupus erythematosus (SLE). Transient HAKATA antigen deficiency was found in 13 patients and appeared to be strongly associated with SLE (11 out of 13). None of the 14 SLE patients had a history of transfusion. It is therefore concluded that anti-HAKATA antibody is produced as one of the autoantibodies in SLE.