Had 4th remicade (infliximab) infusion yesterday for uc. developed severe leg ache and 99.6 deg fever. any advice what to do? can it be remicade (infliximab) induced lupus?

Unlikely!: It is far more likely to be an infection, either viral or bacterial. It is also more likely to be an infusion rxn. You need to stop the drug, for at least for vtwo cycles and talk to your doc about your issues. They need to be looked at quickly.

Doubt lupus : This may or may not be a reaction to remicade (infliximab). It depends on what your evaluation showed. This does not sound like the "drug-induced lupus "rarely found with the use of the tumor necrosis factor inhibitors.