To prepare crust, combine crumbs, margarine, and sugar in a mixing bowl. Press mixture firmly in a 9" pie pan. Chill one hour, or until firm. Or, bake in a 375 oven for ten minutes or until edges are brown. Cool on rack before filling. Preheat oven to 375. To prepare filling, combine cream cheese, sugar, vanilla extract, and egg whites. Spread over crust. Spoon blueberry pie filling on top; cutting through both layers with a knife several times for the swirled effect. Bake for 40 minutes. Serve with remaining blueberry pie filling.