I agree with k3n as far as technically fabrics and threads should match. That means all the cotton we quilters covet should be pieced and quilted with cotton thread. When buying cotton thread buy long-staple, mercerized. You won't have problems with shrinkage or color run from the thread. This is coming from a textile point. Give up all your Coats and Clark lint-producing thread. Go to a good quality all cotton, mercerized thread and you'll probably never have any problems.