If you have used starch or retayne or anything like that on your fabrics, I would wash it in warm water with a good laundry detergent. If you didn't add any chemicals to it, you can just wash in cold water with a small amount of detergent. (or even without it, if the quilt isn't really dirty.)
Even if you didn't add starch or anything like that...
If it's a baby or child's quilt and you didn't prewash the fabrics, wash it at least once and maybe twice in warm water and regular detergent, to remove all the finishing agents, excess dye, etc. Those things are so toxic to little children.