Differential CD4(+) and CD8(+) T-cell responsiveness in hepatitis C virus infection.

This study was performed to compare the vigor and phenotype of virus-specific CD4(+) and CD8(+) T-cell responses in patients with different virologic and clinical outcomes after hepatitis C virus (HCV) infection. The results show that a vigorous and multispecific CD4(+) proliferative T-cell response is maintained indefinitely after recovery from HCV infection whereas it is weak and focused in persistently infected patients. In contrast, the HCV-specific CD8(+) T-cell response was quantitatively low in both groups despite the use of sensitive direct ex vivo intracellular interferon gamma (IFN-gamma) staining. Furthermore, although HCV-specific cytolytic CD8(+) memory T cells were undetectable ex vivo, they were readily expanded from the peripheral blood of chronically HCV-infected patients but not from recovered subjects after in vitro stimulation, suggesting that ongoing viremia is required to maintain the HCV-specific memory CD8(+) T-cell response. HCV-specific CD8(+) T cells displayed a type 1 cytokine profile characterized by production of IFN-gamma despite persistent HCV viremia. The paradoxical observation that HCV-specific CD4(+) T cells survive and CD8(+) T cells are lost after viral clearance while the opposite occurs when HCV persists suggests the existence of differential requirements for the maintenance of CD4(+) and CD8(+) T-cell memory during HCV infection. Furthermore, the relative rarity of circulating CD8(+) effector T cells in chronically infected patients may explain the chronic insidious nature of the liver inflammation and also why they fail to eliminate the virus.

Long-term clinical and histopathological follow-up of chronic posttransfusion hepatitis.

We have evaluated the clinical and histopathological outcomes of patients who contracted chronic non A, non B hepatitis as a result of transfusions administered during heart surgery at the National Institutes of Health. Posttransfusion hepatitis developed in 65 of 1,070 (6.1%) patients and became chronic in 45 (69%) of those cases. Antibody to hepatitis C virus was detectable in 53 patients (82%) with posttransfusion non A, non B hepatitis. Thirty-three patients with chronic non A, non B hepatitis agreed to liver biopsy (group 1). In addition, six other patients with chronic posttransfusion non A, non B hepatitis were evaluated (group 2). These 39 patients were followed between 1 and 24 yr (mean = 9.7 yr). Cirrhosis developed in 8 patients (20%) between 1.5 and 16 yr after blood transfusion. Of the 33 patients in group 1, 11 (33%) died during follow-up. In two cases (6%), this was related to liver failure. At this writing, two additional patients (6%) have decompensated cirrhosis and one (3%) had debilitating fatigue. Twenty of 33 patients (61%) with histological evidence of chronic active hepatitis or cirrhosis are asymptomatic and have no clinical evidence of liver disease. Thus chronic non A, non B posttransfusion hepatitis appeared to be due to hepatitis C virus infection in most cases. It was associated with the development of cirrhosis in approximately 20% of cases and end-stage liver disease in 12% of patients followed prospectively. Most patients with histological evidence of cirrhosis or chronic active hepatitis, however, had minimal clinical evidence of liver disease within the time frame of this study.

Clinical implications of positive tests for antibodies to human immunodeficiency virus type 1 in asymptomatic blood donors.

Of 693,000 volunteer blood donors in Washington, D.C., who were screened for infection with human immunodeficiency virus type 1 (HIV-1) from July 1985 through December 1988, 284 tested positive on both enzyme immunoassay and Western blot assay. To determine the clinical importance of confirmed positive test results in asymptomatic blood donors, we followed 156 donors with positive Western blot assays and 80 donors with positive enzyme immunoassays but negative or indeterminate Western blots at 6-month intervals for a mean of 28 months. As compared with Western blot-negative persons, those with positive Western blots were significantly more likely to be black, male, and first-time donors and to have a history of venereal disease, generalized lymphadenopathy on examination, CD4-cell counts lower than 0.4 x 10(9) per liter, IgG levels higher than 18 g per liter, and antibody to hepatitis B core antigen on initial evaluation. In 17 (11 percent) of the Western blot-positive donors, the disease progressed to Class IV (symptomatic disease), according to the Centers for Disease Control system. CD4 counts below 0.2 x 10(9) per liter, IgA levels above 4 g per liter, abnormal proliferative responses to tetanus toxoid, and positive viral cultures were the strongest predictors of disease progression. Among the 80 donors with repeatedly reactive assay results but either negative or indeterminate Western blot assays, there was no evidence of HIV exposure in their histories, physical examinations, or laboratory evaluations, and manifestations of HIV infection developed in none of them. We conclude that a small number of persons with HIV infection continue to donate blood, despite attempts to exclude them, but that donors who test positive on enzyme immunoassay but persistently negative or indeterminate on Western blot assay probably do not represent a risk for the transmission of HIV.