Characterization of the "a" determinant region of the hepatitis B virus genome in Iranian patients at different clinical phases of chronic infection.

Aim: To determine the distribution of important mutations of the "a" determinant region in the HBV genome among patients in different clinical phases of HBV infection.

Background: Variations in Hepatitis B infection not only change the outcome of the disease but also the symptoms from which the chronic HBV patients are suffering.

Methods: We have meticulously selected a total of 40 chronic HBV patients from four different subclasses of chronic HBV clinical phases including immune tolerant (IT), immune active (IA), inactive carrier (IC) and hepatitis B e antigen (HBeAg)-negative (ENEG); 10 samples per each phase. Mutations of the "a" determinant region were identified using PCR-Direct sequencing method.

Results: 17 amino-acid substitutions at 12 positions inside the "a" determinant were identified in all forty samples; 3 mutations in the IT group, 6 mutations in the IA phase, 3 mutations in the IC patients and 5 mutations in the ENEG phase. Different substitutions were observed in all four clinical phases. The IA phase was the most variant group with the highest number of amino-acid substitutions.

Conclusion: These results did not reveal a strong pattern to distinguish different clinical phases of Chronic HBV infection, but there are some obvious differences regarding the number and position of mutations between these four clinical phases.