HAHA response: the formation of (Human) Antibodies in response to treatment with a (therapeutic) Humanized Antibody.
Induction of a HAHA response is generally undesirable, as the antibodies formed usually have the potential to neutralize the effect of the treatment antibody. Much care is taken to engineer non-human characteristics out of the treatment antibody as far as possible (hence the term 'humanized antibody'), to minimize the chances of it being perceived as 'foreign', thereby triggering a HAHA response in the subject.
The potential for this kind of unwanted immunogenic response is a major concern in clinical tests to evaluate the potential therapeutic benefit of new designer antibodies. In addition to neutralizing treatment activity, it can have clinical sequelae that are actively harmful to the patient.
Detection and accurate quantification of a HAHA response is notoriously difficult.
This phrase comes up in every team meeting I attend. It gives me nightmares.