A skin test for infectious hepatitis

Adaptive Immune Responses in Hepatitis A Virus and Hepatitis E Virus Infections

Both hepatitis A virus (HAV) and hepatitis E virus (HEV) cause self-limited infections in humans that are preventable by vaccination. Progress in characterizing adaptive immune responses against these enteric hepatitis viruses, and how they contribute to resolution of infection or liver injury, has therefore remained largely frozen for the past two decades. How HAV and HEV infections are so effectively controlled by B- and T-cell immunity, and why they do not have the same propensity to persist as HBV and HCV infections, cannot yet be adequately explained. The objective of this review is to summarize our understanding of the relationship between patterns of virus replication, adaptive immune responses, and acute liver injury in HAV and HEV infections. Gaps in knowledge, and recent studies that challenge long-held concepts of how antibodies and T cells contribute to control and pathogenesis of HAV and HEV infections, are highlighted.

Studies on the agent of infectious hepatitis; the disease produced in human volunteers by the agent cultivated in tissue culture or embryonated hen's eggs

The successful cultivation of the virus of infectious hepatitis in chick embryo tissue culture and in the amniotic cavity of the embryonated hen's egg is supported by a comparison of the disease induced in volunteers by the cultivated virus with hepatitis without jaundice resulting from experimental infection with natural infectious hepatitis virus. Both types of viral preparations produced illnesses in comparable percentages of volunteers (83 and 75 per cent, respectively) after similar average periods of incubation (24.4 and 23.4 days, respectively) and of similar average duration (28.3 and 27.6 days, respectively). The disease could be divided in both groups of patients into a primary stage, followed after a short interval of relative well being by the secondary stage. The illnesses in both instances were characterized by anorexia, nausea, vomiting, enlarged, tender livers and abnormal liver function tests, and frequently temperature elevations. They differed in that jaundice was observed in 31 per cent of the cases resulting from infection with natural virus but not in any patients infected with the cultivated virus.

Studies on the agent of infectious hepatitis; propagation of the agent in tissue culture and in the embryonated hen's egg

Two viral agents have been procured from patients with infectious hepatitisin two widely separated outbreaks of the disease by transfer of acute stage serum and stool filtrates to and passage in tissue cultures of rabbit liver cells in roller tubes and minced chick embryos in Simms-Sanders medium followed by passage in the amniotic cavity of the chick. Cultures of both agents, designated the Akiba and NL strains of virus, induced mild hepatitis without jaundice in the majority of volunteers tested after an incubation period of from 9 to 38 days. Although these agents have not been identified definitely as the virus of infectious hepatitis, the available evidence, as discussed, is compatible with the suggestion that such they are.

Studies on the agent of infectious hepatitis. III. The effect of skin tests for infectious hepatitis on the incidence of the disease in a closed institution

At the onset of an epidemic in a closed institution about one-fourth of the inmates were skin-tested. During the year following the skin test, 5 cases of hepatitis with jaundice were recorded among 320 skin-tested individuals with unknown histories, one in the 144 skin test-positive, and 4 in the 176 skin test-negative subjects. In contrast 112 cases occurred among the 825 non-skin-tested individuals. Thus, the incidence of jaundice in the skin-tested group was 1.6 per cent as against 13.6 per cent in the non-skin-tested individuals. Possible explanations for this observation have been discussed.