Incidence and characteristics of HBV reactivation in hematological malignant patients in south Egypt

AIM:To investigate characteristics of hepatitis B virus(HBV)implicated in HBV reactivation in patients with hematological malignancies receiving immunosuppressive therapy.METHODS:Serum samples were collected from 53 patients with hematological malignancies negative for hepatitis B surface antigen(HBsAg)before the start of and throughout the chemotherapy course.HBV reactivation was diagnosed when the HBsAg status changed from negative to positive after the initiation of chemotherapy and/or when HBV DNA was detected by realtime detection polymerase chain reaction(RTD-PCR).For detecting the serological markers of HBV infection,HBsAg as well as antibodies to the core antigen(antiHBc)and to the surface antigen were measured in the sera by CEIA.Nucleic acids were extracted from sera,and HBV DNA sequences spanning the S gene were amplified by RTD-PCR.The extracted DNA was further subjected to PCR to amplify the complete genome as well as the specific genomic sequences bearing the enhancerⅡ/core promoter/pre-core/core regions(nt1628-2364).Amplicons were sequenced directly.RESULTS:Thirty-five(66%)of the 53 HBsAg-negative patients were found to be negative serologically for antiHBc,and the remaining 18(34%)patients were positive for anti-HBc.Five of the 53(9.4%)patients with hematologic malignancies experienced HBV reactivation.Genotype D1 was detected in all five patients.Four types of mutant strains were detected in the S gene product of HBV strains and were isolated from 3 patients with HBV reactivation:T/S120,L143,and I126.HBV DNA was detected in the pretreatment HBsAg-negative samples in one of the five patients with HBV reactivation.In this patient,sequences encompassing the HBV full genome obtained from sera before the start of chemotherapy and at the time of de novo HBV hepatitis were detected and it showed 100%homology.Furthermore,in the phylogenetic tree,the sequences were clustered together,thereby indicating that this patient developed reactivation from an occult HBV infection.CONCLUSION:Past infection with HBV is a risk factor for HBV reactivation in Egypt.Mandatory anti-HBc screening prior to chemotherapy in patients with hematological malignancies is recommended.

Characteristics of escape mutations from occult hepatitis B virus infected patients with hematological malignancies in South Egypt

AIM To investigate the prevalence and virological characteristics of occult hepatitis B virus(HBV) infections in patients with hematological malignancies in South Egypt.METHODS Serum samples were collected from 165 patients with hematological malignancies to monitor titers of HBV DNA, hepatitis B surface antigen(HBs Ag), and antibodies to HBV core(anti-HBc) and surface antigens. Serum samples negative for HBs Ag and positive for anti-HBc were subjected to nucleic acid extraction and HBV DNA detection by real-time polymerase chain reaction. DNA sequences spanning the S region were analyzed in cases with occult HBV infection. In vitro comparative study of constructed 1.24-fold wild type and S protein mutant HBV genotype D clones was further performed. RESULTS HBV DNA was detected in 23(42.6%) of 54 patients with hematological malignancies who were HBsA g negative, but anti-HBc positive, suggesting the presence of occult HBV infection. The complete HBV genome was retrieved from 6 occult HBV patients, and P120 T and S143 L were detected in 3 and 2 cases, respectively. Site directed mutagenesis was done to produce 1.24-fold genotype D clones with amino acid mutations T120 and L143. The in vitro analyses revealed that a lower level of extracellular HBsA g was detected by chemiluminescence enzyme immunoassay(CLEIA) with the clone containing T120 mutation, compared with the wild type or the clone with S143 L mutation despite the similar levels of extracellular and intracellular HBs Ag detected by Western blot. Southern blot experiments showed that the levels of intracellular HBV DNA were not different between these clones. CONCLUSION Occult HBV infection is common in patients with hematological malignancies and associated with P120 T and S143 L mutations. 120 T mutation impairs the detection of HBsA g by CLEIA.