Characterisation of immunofluorescent heterophile antibodies which may be confused with autoantibodies.

Approximately 6% of sera submitted for routine immunofluorescent autoantibody screeening produced characteristic reaction patterns against a variety of animal and human tissues. It is suggested that these non-tissue-specific patterns represent a complex family of heterophile antibodies which could be confused with certain autoantibodies. It is further suggested that these heterophile antibodies bear a relationship to IgG isohaemagglutinins.