Department of Microbial Biotechnology, National Research Center, Cairo, Giza 12622, Egypt.
World J Gastroenterol. 2013 Jan 14;19(2):290-8. doi: 10.3748/wjg.v19.i2.290.
To test whether the status of positive cytomegalovirus (CMV) DNA detection adds to the predictive value of IL28B and to further categorize C/T allele carriers.
This study included 166 chronic hepatitis C (CHC) patients who received combined interferon and ribavirin therapy for 48 wk, 84 spontaneous hepatitis C virus (HCV) resolvers who were positive for IgG anti-HCV antibody and negative for HCV RNA, and 100 healthy subjects who were negative for both HCV antibodies and RNA as controls. Genomic DNA from peripheral blood was used for IL28B rs.12979860 single nucleotide polymorphism (SNP) and CMV DNA detection. A 139 bp fragment containing IL28B SNP was amplified in all subjects by polymerase chain reaction using a specifically designed primer. Then the IL28B rs.12979860 SNP was detected by restriction fragment length polymorphism (RFLP) genotyping. The presence of CMV DNA was tested by amplification of the gB1 gene using nested polymerase chain reaction. The role of CMV and IL28B rs.12979860 SNP genotypes in determining the response rate to combined interferon therapy and clinical status of patients were statistically analyzed.
Current data showed that 67% of patients carrying the IL28B 12979860 C/C allele had a sustained viral response (SVR) while the genotypes C/T and TT were associated with lower SVR rates, 50% and 48%, respectively. SVR rates for the C/C allele were lower than other HCV genotypes and/or other populations. Genotype CC was associated with the response to interferon (P = 0.025). Genotype C/C was reduced from 48% in controls to 14% in CHC patients suggesting its protective role against progression to chronicity. The majority of spontaneously cleared subjects (86%) were C/C, confirming its protective role. The C/T allele was present in 71% of CHC patients compared with 38% of controls, so the use of IL28B SNP genotyping only in these patients may be of little value as a predictor of response. CMV reactivation occurred in 40% of CHC patients. Co-infection with CMV seriously diminished the response to interferon (IFN) therapy, with SVR rates in C/C genotypes 87.5% in CMV-negative patients and 12.5% in CMV-positive patients (P < 0.0001). SVR rates among C/T carriers were reduced to < 50% in patients with positive CMV DNA while the non-response rate doubled. These data indicate that a supplemental assay for CMV viremia adds to the prognostic value of IL28B genotyping.
The results suggest that both genetic (i.e., spontaneous) and therapeutic (IFN-based therapy) arms are complementary in the battle against HCV. CMV DNA testing may be of value to better predict the response to IFN, particularly in IL28B C/T carriers.
检测巨细胞病毒（CMV）DNA 阳性检测的状态是否增加 IL28B 的预测价值，并进一步对 IL28B C/T 等位基因携带者进行分类。
本研究纳入了 166 例接受聚乙二醇干扰素联合利巴韦林治疗 48 周的慢性丙型肝炎（CHC）患者、84 例 HCV 抗体 IgG 阳性而 HCV RNA 阴性的自发性 HCV 病毒（HCV）清除者，以及 100 例 HCV 抗体和 RNA 均为阴性的健康对照者。使用外周血基因组 DNA 进行 IL28B rs12979860 单核苷酸多态性（SNP）和 CMV DNA 检测。采用特异性设计的引物，通过聚合酶链反应（PCR）扩增所有研究对象的包含 IL28B SNP 的 139 bp 片段。然后通过限制性片段长度多态性（RFLP）基因分型检测 IL28B rs12979860 SNP。通过巢式 PCR 扩增 gB1 基因检测 CMV DNA 的存在。采用统计学方法分析 CMV 和 IL28B rs12979860 SNP 基因型在确定联合干扰素治疗反应率和患者临床状态中的作用。
目前的数据表明，携带 IL28B 12979860 C/C 等位基因的患者中有 67%达到持续病毒学应答（SVR），而 C/T 和 TT 基因型与较低的 SVR 率相关，分别为 50%和 48%。C/C 等位基因的 SVR 率低于其他 HCV 基因型和/或其他人群。基因型 CC 与干扰素的应答相关（P=0.025）。CC 基因型从对照组的 48%减少到 CHC 患者的 14%，表明其具有预防慢性化的作用。大多数自发性清除者（86%）为 CC，证实了其保护作用。C/T 等位基因在 CHC 患者中的存在率为 71%，而在对照组中为 38%，因此，在这些患者中仅使用 IL28B SNP 基因分型可能对预测应答的价值不大。40%的 CHC 患者发生 CMV 再激活。CMV 合并感染严重降低了干扰素（IFN）治疗的应答率，CMV 阴性患者的 SVR 率为 87.5%，CMV 阳性患者的 SVR 率为 12.5%（P<0.0001）。CMV DNA 阳性患者中 C/T 携带者的 SVR 率降至<50%，而无应答率增加了一倍。这些数据表明，CMV 病毒血症的补充检测增加了 IL28B 基因分型的预后价值。
研究结果表明，无论是遗传（即自发性）还是治疗（基于 IFN 的治疗）都在对抗 HCV 方面具有互补性。CMV DNA 检测可能有助于更好地预测 IFN 的应答，特别是在 IL28B C/T 携带者中。
