NATAP: New Experimental HBV Therapy

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Oral feeding of hepatitis B proteins a promising treatment for chronic

infection

NEW YORK (Reuters Health) - In patients with chronic hepatitis B virus (HBV)

infection, oral administration of HBV envelope proteins augments the anti-HBV

immune response and alleviates immune-mediated liver damage, results of a new

study indicate. There was a significant decrease in viral load and an

improvement in the histological necroinflammatory score.

Building on earlier research showing that antiviral immunity could be

modulated through oral feeding of viral proteins, Dr. Yaron Ilan from

Hadassah-Hebrew

University Medical Center in Jerusalem and colleagues treated 42 chronic HBV

patients with HBV envelope proteins (HBsAg+preS1+preS2) three times per week

for 20 to 30 weeks.

They followed the subjects for another 20 weeks after the end of the

treatment period. Writing in the December issue of The American Journal of

Gastroenterology, the team reports that the treatment was well tolerated and

that 80% of

those with elevated liver enzymes showed a favorable biochemical response.

Treatment led to a significant decrease in viral load in 15 patients (35.7%),

an improvement in HBsAg and HBeAg scores on liver biopsy in 41% and 57%,

respectively, and in the histological necroinflammatory score in 30%.

Five of 19 HBeAg positive patients (26.3%) became HBeAg negative.

Oral immune regulation toward HBV envelope proteins also significantly

increased HBV-specific T cell proliferation and favorably altered the Th1/Th2

immune

balance by increasing IFN-gamma T cell clones and decreasing IL-10 T cell

clones.

An increase in peripheral blood levels of natural killer T (NKT) lymphocytes

was also noted in all patients.

These results show that " HBV-specific T cell immune modulation can be

elicited through p.o. administration of HBV envelope proteins to chronically

infected

individuals, " Dr. Ilan and colleagues write. This approach " alleviated the

disease, while leaving the general immunological defense of the recipient

intact. "

However, when treatment was halted, HBV DNA levels rebounded in roughly half

of the responders and the antiviral T cell response was lost in 30% to 70% of

responders although IL10 levels remained low.

" It is possible that correction of the anti-HBV immunological imbalance was

partial, leading to an enhanced effect on part of T cell subtypes rather than a

clearance or irreversible suppression of 'unwanted' T cells, " they write.

Am J Gastroenterol 2003;98:2505-2515.

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