Primary gastroesophageal-ileal hodgkin lymphoma

Primary Hodgkin lymphoma of the gastrointestinal tract is exceedingly rare to the point that some authors regard with skepticism the existence of this entity. Cases of gastrointestinal Hodgkin lymphoma have been reported previously; however, most of these cases represented secondary involvement of the digestive tract in the context of systemic disease. Other cases have been reclassified in retrospective studies as non-Hodgkin lymphomas after the application of immunohistochemical techniques. We report a case of primary Hodgkin lymphoma of the gastrointestinal tract in a patient who presented with obstructive symptoms at the site of a gastroileal bypass; the bypass had been performed years earlier because of morbid obesity. Some non-Hodgkin lymphomas may morphologically mimic Hodgkin lymphoma and vice versa; therefore, an accurate pathologic diagnosis is important, since the therapeutic approach and prognostic implications differ significantly for these diseases. In this context, immunohistochemistry should be used to confirm or to exclude the histologic diagnosis of Hodgkin lymphoma.     

Regulation of experimental autoimmune encephalomyelitis by CD4+, CD25+ and CD8+ T cells: analysis using depleting antibodies

Experimental Autoimmune Encephalomyelitis (EAE) can be induced in mice of the C57BL/6 strain by subcutaneous immunization with myelin/oligodendrocyte glycoprotein (MOG) peptide p35-55 in CFA, administered twice at an interval of one week and supplemented with Bordetella pertussis toxin given IV. Here, we studied the effect on the induction of EAE of depleting antibodies to CD4, CD8, or CD25 administered before either the first or the second dose of MOG p35-55. We found that anti-CD4 abolished EAE when given before the first immunization; anti-CD4 did not affect the disease when it was given before the second immunization. Anti-CD8 enhanced EAE induction when given before either of the two immunizations. Anti-CD25 enhanced EAE to the same degree as anti-CD8 when given before the first immunization, but anti-CD25 was even more effective in enhancing EAE when given before the second immunization. The anti-CD25 treatment led to significantly enhanced IFNgamma production by T cells responding to MOG p35-55 and persisting anti-MOG antibodies detectable 56 days after the first immunization. Administration of anti-CD8 or anti-CD25 abolished the need for pertussis toxin to induce EAE. These findings are compatible with the idea that CD4 T cells are required for the initial induction of EAE and that the disease is down-regulated by T cells expressing CD8 or CD25. These regulatory T cells exist prior to MOG immunization, but the CD25+ regulators appear to be further amplified by immunization.     

Isolation and identification of pathogenic Acanthamoeba strains in Tenerife, Canary Islands, Spain from water sources

A comprehensive survey to document the presence of free-living amoebae of the genus Acanthamoeba was conducted in tap water and sea water sources related to human environments in Tenerife, Canary Islands, Spain. Acanthamoeba identification was based on the morphology of cyst and trophozoite forms and PCR amplification with a genus-specific primer pair. The pathogenic potential of Acanthamoeba isolates was characterized by temperature and osmotolerance assays and PCR reactions with two primer pairs related to Acanthamoeba pathogenesis. The results demonstrate the presence of potentially pathogenic strains in both sources. Thus, some of the amoebae in these aquatic habitats can act as opportunistic pathogens, could play a role in the diseases of aquatic organisms, and may present a risk to human health.     

Chemical modifications of band 3 protein affect the adhesion of Plasmodium falciparum-infected erythrocytes to CD36

The role of the erythrocyte anion exchanger, band 3 protein (AE1), in the adhesion of Plasmodium falciparum-infected erythrocytes to CD36 and thrombospondin (TSP) was studied. Two specific anion exchange inhibitors that bind covalently to different regions of the band 3 molecule affected cytoadherence in dissimilar ways. Modification of lysine 539 by diisothiocyanostilbene sulfonic acid (DIDS) resulted in a significant reduction in the adhesive properties of parasitized erythrocytes for CD36, but not TSP, whereas treatment with fluorescein-5-maleimide, which modifies lysine 430, was without effect on both TSP and CD36 binding. The adhesive properties of the DIDS binding region (DBR) was demonstrated by competition experiments using synthetic peptides and by direct interaction of such peptides with CD36 transfected CHO cells. The results suggest that host membrane proteins such as AE1 contribute to the adhesion of malaria-infected erythrocytes to CD36.