Effect of low dosage of interferon on natural killer activity in patients with HBsAg-positive chronic active...

The effect of human leukocyte interferon (IFN) on natural killer (NK) activity in 7 patients with HBsAg-positive chronic active hepatitis was investigated. Human leukocyte IFN was intramuscularly given once a week for 4 consecutive weeks (10 X 10(5), 5 X 10(5), 2 X 10(5) and 1 X 10(5) U). 1 week after the initial injection, NK activity showed a significant rise compared with the preinjection levels (p less than 0.001) and remained elevated during the 1-month treatment, while it fell after the cessation of IFN therapy. 4 of 5 patients showed a marked decrease in Dane particle-associated DNA-polymerase activity. Serum HBeAg disappeared in 3 of 6 patients and serum transaminase levels markedly improved in all patients. Only a transient reduction in HBsAg was observed in 2 patients after the treatment period. The findings indicate that a low dosage of human leukocyte IFN such as 18 X 10(5) U, administered in decreasing doses, enhances NK activity in patients with HBsAg-positive chronic active hepatitis, and that the effect of IFN is involved in the immune mechanisms associated with natural cytotoxicity.