Reply

Abstract

cells facilitated HCV RNA detection in as much as 75% of initially HCV-negative cases. 7 Further, in up to 20% of cases, the HCV genome can be found in stimulated PBMCs but not in parallel serum. The simultaneous detection of an HCV RNA replicative strand, HCV protein, and unique HCV variants served to authenticate active virus replication in PBMCs, irrespective of serum HCV RNA status, as our recent study reassured. 6 The above approach to HCV RNA identification was not employed by Bernardin and colleagues. 1 Thus, as they alluded, it remains a distinct possibility that ex vivo stimulation of PBMCs might have augmented HCV detection in their study. Nevertheless, we recently demonstrated that replication of HCV can be confined to particular immune cell subsets, while total PBMCs appear nonreactive, 6 suggesting that PBMC negativity does not necessarily exclude low-level HCV infection in this compartment.In summary, substantial differences in the methodology by which PBMCs and RNA were prepared, in the amount of template analyzed, and in the overall assay sensitivity are the most probable reasons behind the contradictory findings described by Bernardin et al. 1 and others. [2][3][4][5][6] As such, standardization of methods for HCV RNA detection in circulating immune cells based on the most sensitive approaches uncovered should be considered in future studies on this subject. TRAM N.Q.