Occult Hepatitis B Virus and Hepatitis B Genotypes among Renal Transplant Patients in Khartoum State, Sudan

Background: Occult (Inapparent) Hepatitis B Virus Infection (OBI) distinguished by undetectable HBsAg and detectable anti-Hbc continues to be a great threat to blood safety. We examined the prevalence of OBI and HBV genotypes of OBI among renal transplant patients. Methods: One hundred samples were collected from renal transplant patient from different centers in Khartoum State. The specimens were investigated for HBV Surface Antigen (HBsAg) and HBV core (HBc) antibodies using Immune Enzymatic Assay (ELISA), and HBV DNA using PCR and Real time PCR and for HBV genotypes using Multiplex Nested PCR. Results: A total of 100 clinical samples were tested for HBsAg of which 97 samples (97%) were negative for HBsAg by ELISA and thirty-seven samples (38.1%) were positive for HBc antibodies. All of the 37 samples positive for HBc antibodies were negative for HBV DNA (0.0%) using PCR; Real time PCR detected only 19(51.4%) positive DNA samples; while different HBV genotypes (A,D, and E) and their co-infections thereof were detected in 24(64.9%) samples using Multiplex Nested PCR. The percentage of anti-HBc positivity was higher (42%) in males compared to females (33%). Occult HBV prevalence was almost equal when using Multiplex Nested PCR being 65.2% and 64.3% in males and females respectively while it was higher in females (57.1%) than in males (47.8%) when using Real time PCR. Conclusion: The results indicated a moderate incidence of occult HBV in renal transplant patients in Khartoum, Sudan. These results also indicated that occult HBV may not be detectable using conventional PCR but can be detected by using Real time PCR and Multiplex Nested PCR. Multiplex Nested PCR test can also detect Occult HBV at higher frequency by detecting viral genotypes which cannot otherwise be detected by using Real time PCR alone. This notion is very important to avoid accidental transmission through dialysis machines or blood transfusion.