Anti-P1, allohemagglutinins associated with Clonorchis sinensis and opisthorchis viverrini infections in patients from Southeast Asia.

An automated assay of anti-P1 allohemagglutinins has been carried out on sera of 61 individuals from Southeast Asia : 28 with clonorchiasis, 18 with opisthorchiasis and 15 control subjects. Anti-P1 activity was detected in 61% of the opisthorchiasis sera, 57% of the clonorchiasis sera and in 26.6% of the control subjects. Their concentration, in the sera, was low in control subjects and exceptionally high in clonorchiasis and opisthorchiasis (up to 13 and 22 times the maximum concentration of the control subjects, respectively). In all cases the anti-P1 antibodies were of IgM class. The results suggested that Clonorchis and Opisthorchis were responsible for immunization of the patients, with P1 alloantigen.