Prevalence of antibodies to hepatitis C virus in hemodialysis patients and renal transplant recipients.

This work was carried out to study the prevalence of hepatitis C virus (HCV) infection, its associated risk factors and possible routes of transmission in hemodialysis patients and renal transplant recipients. Ninety five patients and 15 normal controls were included in this study. Patients were classified into 3 groups: Group I (64 hemodialysis patients), Group II (16 renal transplant recipients) and Group III (15 patients with chronic renal insufficiency on conservative treatments). Each individual was subjected to full clinical examination, estimation of serum alanine aminotransferase (ALT), testing for antibodies to hepatitis C virus (anti-HCV), screening for hepatitis B surface antigen (HBsAg), antibodies to hepatitis B surface antigen (anti-HBs) and core antigen (anti-HBc) by modified ELISA technique. Anti-HCV was found in 87.5% of hemodialysis patients, 81.25% of renal transplant patients, 53.3% of the conservative group and in 13.3% of the control group. There was a significant correlation between the presence of anti-HCV and the duration on dialysis in groups I and II (p < 0.05), while no significant correlation was detected between HCV positive cases and the number of units of transfused blood in groups I and II (p > 0.05). Serum ALT was elevated in patients with HCV infection, but there was no significant correlation between the presence of anti-HCV and elevated ALT level among the examined groups of patients (p > 0.05). The prevalence of HCV infection was not correlated with the duration of renal transplantation and the type of immunosuppressive therapy (p > 0.05). Coinfection with HBV and HCV could occur, as previous infection with HBV was demonstrated. Anti-HBc was found in 51.8%, 66.7%, 37.5% of anti-HCV positive patients in groups I, II, II respectively. Anti-HBs was detected in 24.1% and 15.4% of anti-HCV positive in groups I and II. HBsAg was found only in 4.7% of anti-HCV positive hemodialysis.

Measurement of non-specific antibodies in renal transplant patients and the incidence of certain postoperative viral infections.

In this study we assess the level and incidence of panel reactive antibodies which are the main cause of hyperacute rejection in renal transplant. The patients sera were tested against the lymphocytes of standard individuals. The lymphocyte panel had adequate representation of most of known antigens. 11 out of 20 patients (55%) gave positive standard panel test utilizing the microlymphocytotoxic assay. The positivity was recorded at 20 degrees C suggesting that those patients were sensitized. When the recipient sera were treated with Dithiothreitol (DTT) 2 cases showed false cytotoxic antibodies as shown in the negative panel obtained after the DTT treatment. The other nine positive cases showed true cytotoxic by not reacting with DTT. 80% of active CMV infections occurred concomitantly to acute rejection episodes and/or its treatment, suggest a chronologic, possibly causal link between rejection and CMV infection.

Antibiotics and immunity: effects of antibiotics on mitogen responsiveness of lymphocytes and interleukin-2 production.

The immunomodulating properties of antimicrobial drugs may have important implications in prescriptive practice. This is particularly so for patients whose immune system has been compromised. In this study, tetracycline, cephalothin, rifampicin, polymyxin B and nitrofurantoin reduced mitogen responsiveness of both B and T lymphocytes of mouse spleen cells and human peripheral blood lymphocytes in vitro in a dose-dependent fashion. Ampicillin, chloramphenicol, gentamicin, streptomycin and erythromycin had no effect. In the in vivo study none of the antibiotics affected mouse spleen cell transformation in response to mitogen. The addition of interleukin-2 (IL-2) did not prevent the effect of the antibiotics tested on human lymphocytes in vitro. Cephalothin, chloramphenicol and gentamicin decreased IL-2 production by mouse spleen cells in vitro.

Antibiotics and immunity: effects of antibiotics on natural killer, antibody dependent cell-mediated cytotoxicity and antibody production.

We studied the effects of antibiotics on natural killer (NK), antibody dependent cell-mediated cytotoxicity (ADCC) and immunoglobulin production. When human peripheral blood lymphocytes were incubated overnight with the antibiotic before the assay, nitrofurantoin significantly reduced NK but not ADCC activity. Nitrofurantoin also suppressed both spontaneous and interferon-enhanced NK activities in a dose-dependent fashion. Though it did not affect spontaneous ADCC activity, nitrofurantoin suppressed interferon enhancement of ADCC. Chloramphenicol significantly decreased the number of plaque forming cells in mice. In addition to chloramphenicol, tetracycline, rifampicin, cephalothin, polymyxin B and nitrofurantoin reduced mitogen-induced polycloned immunoglobulin synthesis. Results of this study may have clinical relevance, especially in treating immunocompromised patients.