We thank Dr. Blank for pointing out the importance in differentiating a qualitative from a quantitative reverse transcription PCR assay. We agree that the latter would be required to support our conclusion that Complete Thymic Formula was ineffective in our cohort. Our manuscript incorrectly stated that the HCV RNA assay performed by National Genetics Institute (NGI) was qualitative; it was actually a quantitative multicycle reverse transcription PCR assay (HCV SuperQuant PCR assay). The NGI qualitative PCR assay reports only the presence or absence of HCV but does not provide a viral titer, as illustrated in Table 1 of our paper. The NGI SuperQuant technique is frequently referenced and has been used by the Food and Drug Administration for approval of several interferon preparations. Details of the assay are provided by Tong and colleagues (1).

We thank Dr. Frossard for his interest in our paper. We agree that combination therapy is more effective than monotherapy in naive patients. However, his statement that patients in whom interferon monotherapy fails will probably not respond to a new monotherapy is speculative, and the statement that "the only current therapeutic alternative [for monotherapy nonresponders]  ... is a combination of interferon and ribavirin" is incorrect. Infergen (interferon alfacon-1 [Amgen, Thousand Oaks, California], 15 µg three times weekly for 48 weeks) is approved by the Food and Drug Administration for interferon monotherapy in nonresponders and patients with relapse and provides a sustained response rate of 13% and 58%, respectively (2). Our study particularly targeted patients in whom interferon failed because these patients are more likely to seek alternative therapies (especially if such therapies are advertised as effective on the Internet). More important, medical comorbidity limits our ability to treat a significant subset of HCV-infected patients with current Food and Drug Administration-approved medications. Future investigations of both traditional and alternative therapies are warranted. Of note, a workshop titled "Complementary and Alternative Medicine in Chronic Liver Disease" will be held in August 1999 at the National Institutes of Health.