Cell-mediated immunity in patients on hemodialysis: relationship with hepatitis B carrier status

Treatment of chronic viral hepatitis in patients with renal disease

In the last several years, numerous studies on the natural history and outcomes of viral hepatitis in dialysis and transplantation have been reported. Despite these, the management of hepatitis C virus or hepatitis B virus-related liver disease in end-stage renal disease continues to be an area of controversy. This article aims to address the current therapeutic options for patients with renal disease and chronic viral hepatitis.

The use of lamivudine for patients with acute hepatitis B (a series of cases)

There are limited data on the use of lamivudine for patients with severe forms of acute hepatitis B. We report our experience with the use of lamivudine in six patients with acute HBV infection. Lamivudine was justified by disease severity for four patients and by concerns about risk of chronicity for two patients. The diagnoses of the treated patients were: fulminant liver failure (two patients), severe acute hepatitis B, protracted acute hepatitis B, and new HBV infection in the renal dialysis setting (two patients, one with severe liver injury). Serum HBV DNA titres ranged from 10(5) to 10(7) copies/mL prior to commencement of lamivudine. Lamivudine treatment was associated with a decline in serum HBV DNA and serum transaminases in all patients. All but one patient survived. A 58-year-old man with fulminant hepatitis and multiple organ failure died despite antiviral treatment. When possible, HBeAg and HBsAg seroconversion was documented during follow-up. In the absence of a randomized, prospective study of lamivudine in patients with severe acute hepatitis B, our data encourage the use of this safe and well tolerated drug.

Hepatitis B virus infection in Singapore

Although Singapore is in an endemic region for hepatitis B infection, the hepatitis B carriage rate of 5-6% is relatively low. The highest positivity rates for hepatitis B surface antigen (HBsAg) are found in the paediatric age group, with another peak in 40-49 year olds. Studies suggest that, although perinatal transmission is an important route of infection, most children acquire the virus through horizontal transmission between family members. Viral replication continues at a high rate in young carriers and tends to slow down with increasing age. Up to 50% of hepatitis B carriers in Singapore have chronic hepatitis, shown by raised serum ALT values and liver histology, and about 10% are infected with the precore mutant virus. About 20% of carriers have cirrhosis. Among patients with HCC, up to 75% are HBsAg positive, of whom 45% are still viraemic. Mass vaccination against hepatitis B was introduced into Singapore on a voluntary basis in 1983, with compulsory vaccination of babies born to HBeAg positive mothers since 1985. The number of cases of acute hepatitis B has fallen by 60% between 1989 and 1995 although the problems of the longterm complications of chronic hepatitis B still need to be tackled.

Chronic viral hepatitis and the management of chronic renal failure

Effective control measures to reduce the spread of HBV in dialysis units have had a major beneficial impact on the management of patients with chronic renal failure (Table 3). The exact impact of chronic HBV infection on graft and patient survival following RT remains unclear, and the outcome may depend in great part on the severity of the pre-RT liver disease. RT should only be offered to HBV-infected patients after careful consideration of all the pertinent data, including results of liver biopsy. Advances in HBV vaccination may further decrease the risk of infection in patients on HD. Our understanding of HCV is evolving rapidly, but the question of the risk of transmission of HCV within dialysis units is still unsettled and thus recommendations about isolation of HCV-infected patients are not possible. Although RT does not appear to be deleterious in many HCV-infected patients, histologic and clinical evidence of severe liver disease should also prompt caution in offering RT. Longer term studies are required to assess the ultimate effect of RT in patients with HCV. Clearly, subjective improvement of quality of life associated with successful RT compared to chronic dialysis should not be withheld lightly. Pending further experience, use of organs from anti-HCV-positive donors in non-emergent situations is best avoided. The role of antiviral agents in RT recipients with chronic viral hepatitis also remains to be defined. Improved supportive care of patients with chronic renal disease, including erythropoietin therapy, as well as improved tests for anti-HCV screening of donor blood will help to further diminish exposure to HCV in HD units.

Activated and regulatory T lymphocyte populations in chronic hemodialysis patients

T lymphocyte activation after leukocyte membrane interaction may play a role in immune dysfunction associated with hemodialysis (HD). Studies of T-lymphocyte activation markers in HD have yielded conflicting results, perhaps due to the use of a limited number of markers and different measurement techniques. We studied the lymphocyte activation markers CD25 (interleukin-2 receptor), CD38, CDw49b (VLA-2), CD71 (transferrin receptor), and HLA-DR, as well as the surface antigens CD3, CD4, CD7, and CD8 by two-color flow cytometry in 23 chronic HD patients before and after a single dialysis session; we also studied 30 normal controls. There was no increase in the percentage of activated T cells in the controls and in the patients pre- and post-HD. Conversely, the percentage of CD3+/CD71+ (transferrin receptor) cells was significantly decreased in the patients pre-HD compared with the controls (3.6% +/- 0.5% [mean +/- SEM] v 5.9% +/- 0.5%; P < 0.005). A single dialysis session did not alter the percentage of activated subsets, but led to significant depletion in the number (x 10(9)/L) of cells that were CD3+ (1.10 +/- 0.10 v 0.97 +/- 0.09; P < 0.05), CD7+ (1.0 +/- 0.09 v 0.85 +/- 0.08; P < 0.0001), and CD8+ (0.50 +/- 0.06 v 0.37 +/- 0.04; P < 0.001), but not CD4+ cells (0.73 +/- 0.08 v 0.69 +/- 0.07; P = NS). These data indicate that the chronic HD patients at baseline "predialysis" do not appear to have an increased percentage of circulating activated T lymphocyte subsets and that the CD3+/CD71+ subset is in fact decreased.(ABSTRACT TRUNCATED AT 250 WORDS)

Fine needle aspirative biopsy of the liver in HBsAG-positive patients with end-stage renal failure

HBsAg-positive patients with end-stage renal failure have a high prevalence of asymptomatic chronic hepatitis. In order to determine the usefulness of hepatic cytology in the diagnosis of liver disease, the findings of hepatic needle core biopsy (NCB) and fine needle aspirative biopsy (FNAB) were compared in 15 HBsAg-positive uremic patients. The patients, aged 42 +/- 12 years, 14 males, were on hemodialysis for periods ranging from 13 to 105 months. The NCB was processed by standard histologic and immunohistochemical techniques and FNAB by the conventional technique, using the total corrected increment score (TCI). Plasma samples were collected for evaluation of hepatic function and for viral serologic tests. In 15 patients a diagnosis was made by NCB: normal, 7 cases; chronic persistent hepatitis, 4 cases; and chronic active hepatitis, 4 cases. When the patients were allocated into two groups according to the severity of the liver histologic findings [group I--minor changes (normal+chronic persistent hepatitis), 11 patients; group II--major changes (chronic active hepatitis), 4 patients], statistically higher values were found in the major changes group for alanine aminotransferase (49 +/- 33 vs. 24 +/- 11, p = 0.04), gamma-glutamyl transpeptidase [148 +/- 53 vs. 38 +/- 28, p < (minor) 0.02] and TCI (3.7 +/- 1.2 vs. 2.5 +/- 0.8, p = 0.04). In conclusion, liver FNAB can be useful as a screening procedure for the identification of liver histologic changes (minor or major) in uremic HBsAG-positive patients.

Parathyroid hormone dependent T cell proliferation in uremic rats

Chronic renal failure (CRF) is combined with an impairment of the immune system. The T cell may be a target for the action of parathyroid hormone (PTH). Rats with CRF have high blood levels of PTH. Therefore, the present investigation examined some aspects of the T cell function in both normal and CRF rats before and after parathyroidectomy and after an isogenic kidney transplantation. The T cell proliferative response to phytohemagglutinin (PHA) stimulation was significantly higher in peripheral blood mononuclear cell (PBMC) cultures obtained from CRF rats than from normal rats. After parathyroidectomy the T cells of normal as well as of uremic rats could still be significantly stimulated by PHA, but now no significant difference was seen. When CRF was reversed after an isogenic kidney transplantation and PTH reversed to levels in the normal range, the T cell proliferative response to PHA was normalized. Rat PTH 1-84 stimulated in vitro the PHA-induced proliferation of T cells in a dose dependent manner. This effect was significant in CRF rat lymphocytes, but not in lymphocytes obtained from normal rats. Based upon the present results it is suggested that the secondary hyperparathyroidism in chronic uremia is responsible for the enhanced proliferative response to PHA of T cells from CRF rats.