I doubt that colchicine would interfere with your body's ability to fight infections. Basically the way I understand it is that colchicines roll is to alkalinize the area of gout inflammation that is being made acid by the inflammation. This acidity can precipitate more and more uric acid but it's a localized thing.
In general, most people can safely stop the colchicine after a time with colchicine-allopurinol. It is pretty much useful only until the allopurinol has gotten to steady state lowered levels of serum uric acid. I would think the colchicine might only be needed for a couple months or so.
But keep it at the ready in case of a gouty flare up…no drug is better than colchicine for the quick relief of the pain. I would NEVER be without my bottle of colchicine even if I have only used about 10 pills in the last year.