Gus never had an allergic reaction to Remicade. As far as I know, he didn't develop any antibodies to it either..at least none that showed-up in the lab work. The way we found out that Remicade had stopped working was that our doctor decided to do a pill cam study. It showed stricturing. He did a follow-up endoscopy and found two things. (1) the camera was stuck in the duodenum. (2) there was an extremely tight stricture at that location. Luckily, he was able to remove the camera without surgery.
Here's the crazy thing. Even with the camera stuck...my son never had pain due to the obstruction. So, I think the Remicade was great for his pain, but not so much for controlling his disease.