Three visits instead of three years: what the trials show

The idea behind ILIT is simple: put the allergen where the immune response is organised, in a lymph node, and far less of it is needed. The question is whether three small doses do what years of injections do. The trials so far say: often, and not always.

The Zurich pilot

The first randomised trial, in grass pollen allergy, compared three intralymphatic injections over eight weeks with three years of conventional shots. Symptom improvement was similar, and the ILIT group reached it within the first season.

What has held up, and what has not

Later trials in grass, birch, cat and dust mite allergy have mostly found benefit, with a few that did not reach significance, usually with different dosing or intervals. The three-dose, four-week protocol is the one with the most consistent results, which is why most listed practices use it.

How long it lasts

Published follow-up extends to three years in the larger studies, with one small long-term report beyond that. Nobody yet has the ten-year data that exists for conventional immunotherapy, and the trials have been small. That is the honest state of the evidence.