In this paper, we propose a new approach for combining item-based Collaborative Filtering (CF) with Case Based Reasoning (CBR) to pursue personalized information filtering in a knowledge sharing context. Functionally, our personalized information filtering approach allows the use of recommendations by peers with similar interests and domain experts to guide the selection of information deemed relevant to an active user?s profile. We apply item-based similarity computation in a CF framework to retrieve N information objects based on the user?s interests and recommended by peer. The N information objects are then subjected to a CBR based compositional adaptation method to further select relevant information objects from the N retrieved past cases in order to generate a more fine-grained recommendation.