Lymphomagenesis-related gene expression in B cells from sustained virological responders with occult hepatitis C virus infection.

The expression of activation-induced cytidine deaminase, B-aggressive lymphoma, cyclin D1 and serine/threonine kinase 15 genes, among others, is increased in B cells from patients with chronic hepatitis C virus (HCV) infection. It is unknown whether the level of expression of these genes in B cells is increased in patients with hepatitis C who have achieved a sustained virological response (SVR) but who have persistent, detectable HCV RNA, so-called occult infection. Eighty-three patients who achieved and SVR, 27 with detectable HCV and 56 without detectable HCV RNA, 28 chronic hepatitis C patients and 32 healthy controls were studied. RNA was extracted from B cells, and gene expression levels were measured by RT-PCR. Patients with chronic HCV and those who achieved an SVR (with and without persistent low-level HCV RNA) showed a statistically significant higher expression compared to healthy controls, of activation-induced cytidine deaminase (P = 0.004, P < 0.001 and P = 0.002, respectively), B-aggressive lymphoma (P < 0.001, P = 0.001 and P = 0.006) and cyclin D1 (P = 0.026, P = 0.001; P = 0.038). For activation-induced cytidine deaminase patients with an SVR and 'occult infection' had a statistically significantly higher expression level than patients with and SVR without 'occult infection' (P = 0.014). The higher expression levels found for activation-induced cytidine deaminase, together with other genes indicates that these B lymphomagenesis-related genes are upregulated following HCV therapy and this is more marked when HCV can be detected in PBMCs.