Controversial Concepts Regarding T Helper 1 and T Helper 2 Cytokines in Hepatitis C Virus Infected Patients

which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. We have read the article published in your journal written by Sofian et al., entitled " the serum profile of Th1 and Th2 cytokines in treated and non-treated HCV infected individuals " (1). Evidences well documented that the simultaneous elevation of Th1 and Th2 related cytokines during HCV infection may indicate that both (Thl and Th2) cytokine profiles are involved in the pathogenesis of the diseases (2). Moreover, this activated T cell response in HCV infected patients could be regulated by treatment protocols (3). Sofian et al.'s data provides some additional evidence for the involvement of cellular immune response in HCV infections arrest (1). Accordingly, based on the importance of serum profile of Th1 and Th2 cytokines in HCV infected patients, the authors raised the interesting idea that there might be an association between these cytokines and HCV (1). Authors of the present letter believe that Sofian and co-workers' results need to be interpreted with more cautious , because possible puzzles and limitations of their early concepts of Th1 and Th2 cytokines need to be reconsidered. It is almost widely accepted that in addition to Th2 cell type, IL-10 is produced by a broad variety of other cell types including activated macrophages as well as B and T regulatory (Treg) lymphocytes (4). Similarly, IL-2 is also reported to be secreted from all lymphoid cell types in one side and is considered as a common growth factor, in an autocrine and paracrine fashion, for all lymphocytes on the other side (5). Therefore, it seems that Sofian et al. cytokines classifications were not accurately defined and need to be reconsidered. Furthermore, authors used the general word "profile" in the title of their article, but they only analyzed two cytokines in Th1 and Th2 classes. Thus, it does not mean that they studied the whole Th1 and Th2 cytokines profiles in the study. Additionally, the authors