Mitogenic activation of the human lymphocytes induce the release of proenkephalin derived peptides.

Several reports indicate that enkephalins participate in lymphocyte proliferation and several events of the immune response. It has been proposed that peptides involved in these processes may originate in the nervous system or endocrine glands. We have found that human peripheral blood lymphocytes (PBL) activated with a mitogenic agent contain and release proenkephalin derived peptides. The kinetics of met-enkephalin and cryptic products of proenkephalin in PBL activated with phytohemaglutinin (PHA) were studied. Peptides were released to the supernatant of stimulated PBL, reaching the highest values after 18 to 24 hours. The material secreted corresponds to high, intermediate and low molecular weight peptides derived from proenkephalin, displaying met-enkephalin and synenkephalin (proenkephalin 1-70) immunoreactivity. Therefore, an intrinsic lymphocytic proenkephalin system is induced by PHA and may play an important role in the regulation of the immune response.

Anti-delta antibody in various HBsAg positive Argentine populations.

One thousand five hundred and seventeen HBsAg carriers from different cities of Argentina were studied for the presence of anti-Delta antibody (anti-HDV) in their sera. One thousand one hundred and sixty-eight were volunteer blood donors and 349 were patients with liver disease. Different liver diseases were diagnosed by clinical, biochemical, and histological parameters. Among blood donors, 16 (1.4%) were positive for the antibody and none was Delta-antigen positive. In 130 patients with acute hepatitis, one (0.77%) was positive for anti-HDV, as well as three (2.22%) out of 135 patients with chronic active hepatitis (CAH), and three (5.77%) out of 52 patients with cirrhosis (C). No anti-HDV positive was found among seven fulminant hepatitis (FH) cases. The presence of HBeAg and anti-HBe was studied in anti-HDV positive sera; eleven (69%) volunteer blood donors were anti-HBe positive, and five (31%) were HBeAg positive. HBeAg was positive in the three CAH cases, and in one out of three C Cases with anti-HDV positive. Hepatitis Delta antigen was also positive in the hepatocytic nuclei in the three patients with C and two of the three CAH cases. The present results show that Delta infection is rare among blood donors in Argentina. A small variation without statistical significance could be found within different geographical areas. Among patients with HBsAg related liver disease, the presence of HDV markers was also low.