Transfusion transmitted infectious agents, excluding hepatitis and human immunodeficiency viruses

A number of viruses, parasites and bacteria can be transmitted by blood. Blood seronegative for cytomegalovirus (CMV), effectively prevents CMV infection in seronegative bone marrow recipients. Such blood is available at larger blood transfusion services. Immune anti-CMV globulin can also be helpful in protection of transplant recipients. Human T-lymphotropic virus, type 1 (HTLV-1) causing leukemia and myelopathy can also be transmitted by blood. Blood banks are considering donor screening in areas where the prevalence of this virus is significant. Parvoviruses that may cause crises in haemolytic anaemias present a potential hazard of transfusion. Malaria and syphilis are currently not very important infectious complications of transfusion, whereas prolonged storage of platelets has reemphasised the risk of bacterial growth in blood products.     

Studies on the membrane glycoprotein defect of En(a-) erythrocytes. III. N-terminal amino acids of sialoglycoproteins from normal and En(a-) red cells

Sodium dodecylsulphate polyacrylamide gel electrophoretic methods and quantitative analyses of the N-terminal amino acids were applied to the sialoglycoprotein mixture and glycoprotein fractions from normal erythrocyte membranes, as well as preparations from red cells of individuals belonging to the English and Finnish En(a-) families. The data confirm the observation by alternative methods that SS cells exhibit a higher Ss glycoprotein content than ss erythrocytes. The results of end-group analyses suggest that the N-terminal amino acids serine and leucine represent the structures differentiating the MN and the 'M' and 'N' antigens on the MN and Ss glycoproteins respectively. Data from peptide sequence analyses confirm that the glycine/glutamic acid polymorphism at the fifth position of the MN glycoprotein's peptide chain is closely or absolutely linked with the serine/leucine polymorphism at its N-terminal position. As normal (EnaEna) red cells exhibiting 'M' antigenic properties have not been detected, the hypothesis is proposed that the Ss glycoprotein of English En(a-) erythrocytes possesses an MN-Ss hybrid polypeptide chain analogous to those of the delta-beta Lepore haemoglobins.     

Weak Anti-IgA Antibodies with Limited Specificity and Nonhemolytic Transfusion Reactions

Anti-IgA antibodies were studied in sera from patients with nonhemolytic transfusion reactions for which no serological reason had been found. Of the 158 sera that were studied by passive hemagglutination assay using twelve IgA myeloma proteins, 4 samples had class-specific antibodies and 10 samples antibodies with limited specificity. Titers were 1:8 or less. 100 multitransfused hemophilia patients were studied with two IgA myeloma proteins. Four of the sera had anti-IgA antibodies. Normal blood donor sera reacted with IgA only when antigens were first either digested with pepsin or stored for several months as dilute solutions in refrigerator. The results emphasize the need for fresh IgA proteins of good quality when human anti-IgA antibodies are investigated.     

Cytopathogenesis of <Emphasis Type="Italic">Naegleria fowleri</Emphasis> Thai strains for cultured human neuroblastoma cells

The aim of this study is to evaluate cellular interaction between free-living amoebae Naegleria fowleri strains and mammalian target cells in vitro. Two Thai strains of N. fowleri; Khon Kaen strain from the environment and Siriraj strain from the patient’s cerebrospinal fluid and the Center of Disease Control VO 3081 strain from Atlanta (US) were studied. Human neuroblastoma (SK-N-MC) and African Green monkey Kidney (Vero) cells were used as target cells. Each cell line was inoculated with each strain of N. fowleri at a ratio of 1:1 and observed for 7 days. The uninoculated target cells and each strain of N. fowleri were used as control. The numbers of the challenged and unchallenged cells as well as the free-living amoebae were counted three times by trypan blue exclusion method. The inoculation began when the amoebae attached to the cell membrane and ingested the target cells. In this study, extensive cytopathogenesis with many floating inoculated cells and abundant number of amoebae were observed. The destruction pattern of both inoculated SK-N-MC and Vero target cells were similar. Interestingly, SK-N-MC was more susceptible to N. fowleri strains than the Vero cell. In addition, N. fowleri Siriraj strain showed the highest destruction pattern for each target cell. Our findings suggest that the SK-N-MC should be used as a base model for studying the neuropathogenesis in primary amoebic meningoencephalitis patients.     

STUDIES ON THE MEMBRANE GLYCOPROTEIN DEFECT OF En(a-) ERYTHROCYTES

En(a-) and En^aEn red cells from different sources were studied using biochemical and serological methods. The results suggest that Finnish En(a–) erythrocytes contain only ‘N’ but no M antigenic properties. Data on the members of the English En(a-) family suggest that English En(a-) red cells exhibit a combination of three rare alterations. The English En(a–) individuals are apparently heterozygous for the defects En and M^k. In addition, the ‘N’ receptor on the Ss glycoprotein is, to all appearances, converted to a M (‘M’) antigen. These extraordinary data are brought to light by investigations on the children of the propositus (G.P. and J.P.), whose red cells are M-N+S-s+‘N’+‘M’- and M-N+S+s+‘N’+‘M’+ respectively. Sodium dodecylsulphate polyacrylamide gel electrophoretic results indicate that the MN glycoprotein content is decreased by about 50 % in all English S+s+En^aEn red cells, the Ss glycoprotein being normal. G.P. erythrocytes, however, have only about half of the normal MN and Ss glycoprotein content.