Disclosed is a filtration article comprising a first layer comprising porous PTFE for fluid filtration (e.g., a PTFE membrane), and a second layer comprising strands of fluoropolymer fibers arranged to form a stable knit. The knit layer comprises interlocking regions that are each defined by corresponding sets of at least two interlocking loop portions of the fluoropolymer fiber strands. In filtration article embodiments, the fluoropolymer fiber strands may be twisted and/or have a rounded outer configuration. The knit layer provides improved dimensional stability as a support layer for the filtration layer and/or as a drainage layer.