Genotyping of Hepatitis B and the Response to Treatment with Interferon in Perinatally Infected Children

Elizabeth Boxall, HPA

Elizabeth Boxall, Shamima Kaskar,

Health Protection Agency, west Midlands Public Health laboratory, Heart of England Trust.

The hepatitis B genotype of a group of perinatally infected children, enrolled in an interferon treatment study, were genotyped using a commercial line probe assay (InnoLipa). All 48 samples studied were clearly typed into single genotypes. The genotype results agreed with the geographical origin of the families of the children, with the majority of South Asian children having genotype D and European and Afro-Caribbean children more likely to have genotype A.  The InnoLipa assay could be used to type samples with viral load down to 1 x 104 copies/ml. Typing by InnoLipa was compared in 19 of the children by direct sequencing and the same genotypes were observed, thereby validating the assay. Response to treatment was better in genotypes A and D. Pyhlogenetic analysis showed the relationship between the genotypes and relationships between siblings and mothers and in the European children showed a cluster in children adopted from Romania. The InnoLipa assay proved reliable and easy to use and would be a suitable assay for use in a routine laboratory is there is a developing need for genotyping studies prior to treatment for hepatitis B.