Hepatitis E virus antibodies in hemodialysis patients: an epidemiological survey in central Greece.

Hepatitis E virus (HEV) is the causative agent for enteric non-A, non-B hepatitis. Transmission is mainly via the fecal-oral route but the possibility of an additional parenteric transmission has been raised. Patients undergoing chronic hemodialysis (HD) have an increased risk of exposure to blood transmitted agents. Previous studies concerning prevalence of antibodies to HEV (anti-HEV) among HD patients gave conflicting results. The aim of the study presented here was to determine the prevalence of anti-HEV among HD patients of a well-defined semi-rural region in central Greece (Thessalia region). All patients (n=351, 234 males, mean age 60+/-14 years) who were being treated in the HD units of central Greece (n=5) during 2001 were tested for anti-HEV antibody. Two commercially available specific solid-phase enzyme-linked immunoassays were applied for anti-HEV detection. Hepatitis B virus markers, antibodies to HCV, HIV and HTLV were also screened in all patients by commercially available assays. Serum aminotransferase (AST, ALT) levels were measured by spectrophotometry. 17 anti-HEV-positive patients were found and prevalence was 4.8%, varying from 1.8 - 9.8% in the various HD units. Prevalence of HBsAg and anti-HCV was 5.7% (2.9 - 15%) and 23.6% (11.5 - 36.2%) respectively. The anti-HEV prevalence was increased compared to healthy blood donors in Greece (0.26%, p < 0.01). The highest prevalence of anti-HEV was seen at the HD unit of the General Hospital of Karditsa (9.8%). Risk factors for anti-HEV antibody were not identified: no association was found between anti-HEV positivity and age or sex, duration of HD, hepatitis B or C virus infection markers, previously elevated aminotransferase levels or history of transfusion. Our investigation of HEV infection in the cohort of HD patients in central Greece showed that the prevalence of anti-HEV was greater than in healthy blood donors. There was no association to blood borne infections (HBV, HCV). The high prevalence of anti-HEV we found in one HD unit was probably related to a local infection in the past. However, long-term prospective studies are needed in an attempt to identify whether intra-unit factors are also responsible for the increased prevalence of serologic markers of HEV infection among HD patients.

The role of T-helper lymphocytes in priming for experimental autoimmune glomerulonephritis in the BN rat.

In our model of experimental autoimmune glomerulonephritis (EAG), BN rats given a single IM injection of homologous glomerular basement membrane (GBM) in FCA develop anti-GBM autoantibodies with focal glomerulonephritis. To investigate the role of lymphocytes in the induction of EAG, we examined the effects of antigen rechallenge and of adoptive cell transfer from donors with nephritis to naive recipients. Groups of animals were rechallenged with GBM in FCA following either low (non-nephritogenic) doses of GBM, or following resolution of EAG. This resulted in an enhanced anti-GBM antibody response in both groups, suggesting the presence of GBM specific T or B memory cells. To investigate this possibility, spleen cells from animals with EAG were transferred into lightly irradiated recipients. There was no significant rise in anti-GBM antibody levels after transfer. However, subsequent challenge with GBM in FCA resulted in an enhanced anti-GBM antibody response by 2 weeks when compared with recipients of normal spleen cells. Cells capable of priming for EAG developed by week 4 after immunization of donors and persisted in the recipients for at least 24 weeks. To investigate which cell type was responsible for this effect, we depleted or positively selected donor spleen cells prior to transfer, using Dynabeads coated with monoclonal antibodies to Th or B lymphocytes. Depletion of Th cells, but not B cells, reduced the enhanced anti-GBM antibody response of recipients challenged with GBM in FCA. Positively selected Th cells, but not B cells, resulted in an enhanced anti-GBM antibody response similar to that in positive controls. These results demonstrate the presence of immunological memory for the autoantigen and show that priming for EAG is mediated by Th lymphocytes.

Increased natriuretic ability and hypotensive effect during short-term high calcium intake in essential hypertension.

The present study has investigated whether an increased natriuresis could account for the hypotensive effect of a high calcium diet which has been reported by others. A calcium supplement (equivalent to 1 g of elemental calcium) was given for 5 days to 18 patients with essential hypertension in a randomized single-blind, placebo-controlled, cross-over trial. In 15 of the patients, 2 liters of isotonic saline were infused intravenously over 4 h during the last day of each test period and hourly urine collections were taken. Calcium supplementation produced a mild but significant hypercalcemia as well as increased urinary calcium excretion. Body weight and systolic blood pressure decreased significantly. The blood pressure decrease was indirectly related to the pretreatment plasma renin activity (r = -0.61, p less than 0.01). Urinary sodium excretion increased during calcium diet (80 mmol/day negative balance, p less than 0.01). During saline infusion under calcium supplementation the urine volume, osmolality and sodium excretion were significantly higher compared with placebo. The changes in urinary sodium excretion correlated positively with the changes in urinary calcium excretion (r = 0.68, p less than 0.01) in patients given the high calcium diet, when infused with saline. We conclude that calcium supplementation induces a considerable sodium loss in the urine which is very likely to result in the hypotensive effect.

Effect of ticlopidine on coagulation and platelet functions during hemodialysis with cuprophan membranes.

The study is a comparison of two successive HD sessions on each patient. 60 min prior to the first session a placebo was administered orally, while to the second session 500 mg ticlopidine. Arterial blood samples for leucocyte and platelet counts, C3 complement, blood gases, beta-thromboglobulin (beta-TG) and platelet factor 4 (PF-4) measurement were taken before and 15, 30, 60, 120, 240 min during each HD session. Platelet aggregation (ADP 1 microM/ml) was also carried out pre and post-dialysis. It is suggested that ticlopidine: 1) prevents HD-induced complement activation and related phenomena, 2) normalize the increased plasma levels of platelet markers 3) inhibits the ADP-induced platelet aggregation.

Biocompatibility of cuprophan and cellulose acetate membranes. Prevention of dialysis hypoxemia and leucopenia by ticlopidine.

The study is a comparison of 4 successive hemodialysis (HD) sessions on each patient, 2 with cuprophan (CU) membrane (Gambro 120 M) and 2 with Cellulose acetate (CA) (Cordis Dow 3500). 60 minutes prior to the HD session placebo or Ticlopidine (500 mg) was administered orally to each patient. Leucocyte and platelet counts, serum C3 complement, arterial PO2, PCO2 and PH were measured before and 15, 30, 60, 120 and 240 minutes after the beginning of HD. Leucocyte count fell markedly within 15 minutes of both placebo HD sessions, but it was significantly lower (p less than 0.005) in CA than CU membrane. Ticlopidine prevented significantly (p less than 0.01) the HD-induced leucopenia. Slight changes in platelet count, either in placebo or Ticlopidine study were observed. Serum C3 complement increased significantly (p less than 0.05) at 15 minutes of CU placebo session and was also correlated (p less than 0.01) with the concurrent leucopenia. The arterial PO2 decreased 22% and 13.5% during HD with CU and CA membranes respectively, but it was preserved within normal limits by Ticlopidine. The arterial PH was increased up to 7.4 at the end of all HD sessions, while PCO2 showed only slight changes. We conclude that: 1) CA membrane is better tolerated than CU 2) HD-induced leucopenia and hypoxemia are prevented by Ticlopidine, probably by modulating the complement activation.