There is only one unpardonable sin...Unbelief in Jesus Christ...
Religious pride is unpardonable. The Pharisee's saw Christ work true miracles and attributed it to the work of the devil. They knew better! they were the theologians of their day and knew that only God can produce true miracles.
Those who deny the Eucharist is Christ who have full knowledge that God is capable of transubstantiation do the same thing.