El-Mokhtar Mohamed A, Hetta Helal F, Mekky Mohamed A, Abd El-Kareem Doaa M, Ramadan Mohammed, Salah Mohammed, Mohamed Nahed A, El-Masry Eman A, Adel Sara, Sayed Ibrahim M
Department of Medical Microbiology and Immunology, Faculty of Medicine, Assiut University, Assiut, 71515, Egypt.
Department of Tropical Medicine and Gastroenterology, Assiut University Hospital, Assiut, Egypt.
Infect Drug Resist. 2021 Jun 28;14:2419-2427. doi: 10.2147/IDR.S315299. eCollection 2021.
Mutations within the "a" determinant region (position 124-147) that is present in the major hydrophilic region (MHR, position 99-160) of the hepatitis B surface antigen (HBsAg) are associated with vaccine-escape, lack of diagnosis, and failure to hepatitis B immunoglobulin (HBIG) therapy. Data regarding the amino acid changes of "a" determinant region of HBsAg are limited in Egypt. The prevalence and mutations in this region among chronic HBV (CHB)-infected patients in Upper Egypt are not known.
Blood samples were collected from HBsAg-positive CHB-infected patients (n=123) admitted to Assiut University Hospitals. Serum samples were screened for HBsAg, HBeAg, anti-HBs and anti-HBe antibodies using commercially available ELISA kits. Viral load was determined by qPCR. In addition, mutational analysis was carried out targeting the HBV surface gene to determine the HBV genotype and vaccine escape mutations.
Sequencing analysis of HBV DNA revealed that genotype D is the major circulating type (81.3%), followed by genotype E (18.7%). Analysis of the HBV genome revealed that 103/123 (83.7%) patients showed wild-type sequences and 20/123 (16.3%) showed mutations in the HBsAg gene. Mutation in seventeen patients (17/20, 85%) showed only one mutation, and three patients showed two mutations (3/20, 15%) in the "a" determinant region. The observed mutations were T115S (3/20, 15%), P120T/S (3/20, 15%), T126S (1/20, 5%), Q129R (2/20, 10%), M133T (2/20, 10%), S143L (5/20, 25%), D144E/A (3/20, 15%), and G145R/A (4/20, 20%). Mutations in the "a" determinant region were detected in genotype D isolates only.
We described for the first time the prevalence and characterization of vaccine escape mutants in CHB patients in Upper Egypt. Mutational analysis of the "a" determinant region revealed the presence of a wide spectrum of mutants in the circulating HBV isolates that could be a potential threat to HBV diagnosis, therapy success, and HBV vaccination program in Upper Egypt.
乙型肝炎表面抗原（HBsAg）主要亲水区（MHR，第99 - 160位）中“a”决定簇区域（第124 - 147位）内的突变与疫苗逃逸、诊断失败以及乙型肝炎免疫球蛋白（HBIG）治疗无效相关。埃及关于HBsAg“a”决定簇区域氨基酸变化的数据有限。上埃及地区慢性HBV（CHB）感染患者中该区域的患病率和突变情况尚不清楚。
从阿斯尤特大学医院收治的HBsAg阳性CHB感染患者（n = 123）中采集血样。使用市售ELISA试剂盒检测血清样本中的HBsAg、HBeAg、抗 - HBs和抗 - HBe抗体。通过qPCR测定病毒载量。此外，针对HBV表面基因进行突变分析以确定HBV基因型和疫苗逃逸突变。
HBV DNA测序分析显示，D基因型是主要的流行类型（81.3%），其次是E基因型（18.7%）。HBV基因组分析显示，123例患者中有103例（83.7%）表现为野生型序列，20例（16.3%）在HBsAg基因中出现突变。17例患者（17/20，85%）的突变仅表现为一个突变，3例患者（3/20，15%）在“a”决定簇区域出现两个突变。观察到的突变有T115S（3/20，15%）、P120T/S（3/20，15%）、T126S（1/20，5%）、Q129R（2/20，10%）、M133T（2/20，10%）、S143L（5/20，25%）、D144E/A（3/20，15%）和G145R/A（4/20，20%）。仅在D基因型分离株中检测到“a”决定簇区域的突变。
我们首次描述了上埃及地区CHB患者中疫苗逃逸突变体的患病率和特征。“a”决定簇区域的突变分析揭示了循环HBV分离株中存在广泛的突变体，这可能对上埃及地区的HBV诊断、治疗成功以及HBV疫苗接种计划构成潜在威胁。
