The invention relates to a method for manufacturing an anti-RhD recombinant polyclonal antibody composition (anti-RhD rpAb). The method comprises obtaining a collection of cells transfected with a library of anti-RhD antibody expression vectors, wherein each cell in the collection is capable of expressing from a VH and VL comprising nucleic acid segment, one member of the library, which encodes a distinct member of anti-RhD recombinant polyclonal antibody composition and which is located at the same site in the genome of individual cells in said collection. The cells are cultured under suitable conditions for expression of the recombinant polyclonal antibody, which is obtained from the cells or culture supernatant. The nucleic acid segments encoding the anti-RhD rpAb is introduced into the cells by transfection with a library of vectors for site-specific integration. The present method is suitable for manufacturing anti-RhD rpAb, thereby making available a superior replacement of plasma-derived prophylactic and therapeutic immunoglobulin products.