CD4 and AIDS: Literature searches covering articles published between 2000 and 2012 were performed in PubMed/MEDLINE, China National Knowledge Infrastructure (CNKI, http://www.cnki.net), and Wanfang Medicine Online (http://med.wanfangdata.com.cn), using the following key search words: ‘TLC or total lymphocyte count’ and ‘CD4 count’ and ‘HIV or AIDS’.