A filter for filtering fluid flowing along an axial flow direction comprising at least one cylindrical pleated outer filter element having an axis extending along said axial flow direction, said filter element having a plurality of pleats defined by wall segments extending radially in serpentine manner between inner and outer sets of pleat tips at inner and outer sets of axially extending bend lines, said wall segments extending axially between upstream and downstream ends, said wall segments defining axial flow channels therebetween, said upstream ends of said wall segments being alternately sealed to each other to define a first set of flow channels having open upstream ends, and a second set of flow channels interdigitated with said first set of flow channels and having closed upstream ends, said downstream ends of said wall segments being alternately sealed to each other such that said first set of flow channels have closed downstream ends, and said second set of flow channels have open downstream ends, such that fluid to be filtered flows substantially directly axially through said filter, through said open upstream ends of said first set of flow channels then through said wall segments then through said open downstream ends of said second set of flow channels, a central filter element concentrically surrounded by said cylindrical pleated filter element and sealed thereto, said central filter element providing additional flow axially therethrough, wherein said central filter element is a cylindrical pleated filter element having a plurality of pleats defined by wall segments extending radially in serpentine manner between inner and outer sets of pleat tips at inner and outer sets of axially extending bend lines, said wall segments of said central filter element extending axially between upstream and downstream ends, said wall segments of said central filter element defining axial flow channels therebetween, said upstream ends of said wall segments of said central filter element being alternately sealed to each other to define a first set of flow channels having open upstream ends, and a second set of flow channels interdigitated with said first set of flow channels of said central filter element and having closed upstream ends, said downstream ends of said wall segments of said central filter element being alternately sealed to each other such that said first set of flow channels of said central filter element have closed downstream ends, and said second set of flow channels of said central filter element have open downstream ends, such that fluid to be filtered flows substantially directly axially through said central filter element, through said open upstream ends of said first set of flow channels of said central filter element then through said wall segments of said central filter element then through said open downstream ends of said second set of flow channels of said central filter element, wherein said central filter element has a hollow interior having an open end at said other of said upstream and downstream ends of said central filter element and having a closed end at said one of said upstream and downstream ends of said central filter element, said open end of said hollow interior of said central filter element providing additional fluid flow axially therethrough, said central and outer filter elements having a radial gap therebetween at said one of said upstream and downstream ends of said central filter element, and wherein said filter is mounted in a housing having an axially extending sidewall spaced radially outwardly of said outer filter element by a second radial gap at said other of said upstream and downstream ends of said outer filter element, said sidewall also being spaced radially outwardly of said second filter element by an annular gap between said sidewall and said outer set of pleat tips of said second filter element, said second gap providing additional fluid flow axially therethrough and through said annular gap, wherein said central filter element has a hollow interior having an open end at said other of said upstream and downstream ends of said central filter element and having a closed end at said one of said upstream and downstream ends of said central filter element, said open end of said hollow interior of said central filter element providing additional fluid flow axially therethrough, said central and outer filter elements having a radial gap therebetween at said one of said upstream and downstream ends of said central filter element, and wherein said filter is mounted in a housing having an axially extending sidewall spaced radially outwardly of said outer filter element by a second radial gap at said other of said upstream and downstream ends of said outer filter element, said second gap providing additional fluid flow axially therethrough.