Association between secretor status and respiratory viral illness

Genetics of infectious disease resistance

The identification of large numbers of candidates genes and the introduction of methodologies for whole-genome screening have provided new opportunities for elucidating the molecular basis of variable susceptibility to major infectious diseases. 12 genes have been implicated in variable susceptibility to malaria and susceptibility/resistance genes for several other infectious diseases are beginning to be identified. Recent work suggests that large-scale family linkage and population association studies will be a more successful route to human disease genes than extrapolation from mouse models of infection.

Lewis phenotype, secretor status, and coeliac disease

Patients who cannot secrete ABO and Lewis blood group antigens into body fluids, an ability controlled by a single gene on chromosome 19, are known to be at increased risk of certain autoimmune diseases associated with human leucocyte antigen (HLA) markers. This study investigated the possibility of an association with coeliac disease using red cell Lewis (Le) blood group phenotype to infer secretor status. Among 73 patients with coeliac disease who had Le a or b antigen, 48% were non-secretors (Le a + b-) compared with 27% of 137 blood donors (p = 0.004: odds ratio 2.49, 95% confidence intervals 1.37 to 4.51) and 26% of 62 medical and nursing staff controls (p = 0.014: odds ratio 2.65, 95% confidence intervals 1.27 to 5.50). Clinical characteristics did not differ between secretors and non-secretors with coeliac disease. Thus, the non-secretor state is significantly associated with coeliac disease, suggesting that genes on chromosome 19 may directly or indirectly participate in conferring susceptibility.

Detection of microbial surface antigens that bind Lewis(a) antigen

There is evidence that the Lewis(a) blood group antigen is one of the receptors for a number of potentially pathogenic microorganisms. To determine how widely distributed the microbial adhesins are that bind this antigen, anti-idiotypic antibodies produced against monoclonal anti-Lewis(a) were used in coagglutination assays to screen a variety of species. The following were agglutinated: 7/7 strains of Staphylococcus aureus; 10/19 (53%) strains of Neisseria meningitidis; 8/13 (62%) strains of Haemophilus influenzae; 1/3 strains of Helicobacter pylori; 1/2 strains of Neisseria gonorrhoeae; 1/2 strains of Candida albicans. The application of the anti-idiotypic antibodies to studies of host cell receptors, isolation of adhesins and development of new epidemiological typing reagents is discussed.

Parental smoking and carriage of Neisseria meningitidis among Greek schoolchildren

In December 1990 and January 1991, primary (320) and secondary (697) pupils in 2 areas of Athens were screened to determine the rate of carriage of Neisseria meningitidis and to determine if the genetic and environmental factors associated with carriage of meningococci in Greece were similar to those observed for northern European populations. In 1 area, socioeconomic indicators were significantly lower than in the other (p < 0.0005), but the isolation rates from pupils in the areas were similar, 5.3% and 6.3%. In contrast to studies in northwest Europe, carriage was not associated with lower socioeconomic conditions, sex, numbers of individuals per household, upper respiratory tract infection, or secretor status. By univariate analysis, carriage was associated with age (15-18 years) (p < 0.05) and mother's or other carer's smoking habits (p < 0.05)--but not father's smoking. Although the proportion of fathers who smoked was greater in the area where socioeconomic indicators were lower (61%) vs. (47%) (p < 0.0005), the proportions of women smokers were similar (33% vs. 38%). By multiple regression analysis, the only significant factors were age (p < 0.01) and carer's smoking (p < 0.05).

The potential role of bacterial toxins in sudden infant death syndrome (SIDS)

Toxigenic bacteria have been implicated in some cases of Sudden Infant Death Syndrome (SIDS). Although there is not much evidence that Clostridia spp. are associated with SIDS in Britain, strains of Staphylococcus aureus producing pyrogenic toxins have been isolated from significant numbers of these infants at autopsy The pyrogenic toxins, produced by some strains of group A Streptococcus pyogenes as well as staphylococci, are powerful "superantigens" that have significant physiological effects including induction of fever > 38 degrees C. In this article, interactions between genetic and environmental factors that might enhance colonization of epithelial surfaces by toxigenic staphylococci are analyzed: infant's expression of Lewis(a) antigen which acts as a receptor for some microorganisms; viral infections; the effect of mother's smoking on susceptibility to respiratory infection. Based on epidemiological findings and laboratory investigations, a hypothesis is proposed to explain how bacteria producing pyrogenic toxins might contribute to some cot deaths.

Assessment of Lewis blood group antigens and secretor status in autopsy specimens

The ability of enzyme linked immunosorbent assays (ELISA) to detect Lewis and H antigens in secretions obtained from 280 autopsies was assessed. The ELISA results were compared with those for matched blood specimens examined by agglutination of erythrocytes by monoclonal anti-Lewis(a) and anti-Lewis(b) antibodies. There was good agreement between the results for the two tests and the ELISAs could be used to determine secretor status of the subject. While determination of ABO group with monoclonal anti-A and anti-B was possible even with lysed blood, the results for Lewis typing by erythrocyte agglutination were poor if the sample was lysed or partially lysed. Detection of the antigens by ELISA was as efficient among elderly subjects as among younger ones and both H and Lewis antigens could be detected on erythrocytes and in secretions up to 127 h after death.

Factors enhancing adherence of toxigenic Staphylococcus aureus to epithelial cells and their possible role in sudden infant death syndrome

Toxigenic strains of Staphylococcus aureus have been suggested to play a role in sudden infant death syndrome (SIDS). In this study we examined two factors that might enhance binding of toxigenic staphylococci to epithelial cells of infants in the age range in which cot deaths are prevalent: expression of the Lewis(a) antigen and infection with respiratory syncytial virus (RSV). By flow cytometry we demonstrated that binding of three toxigenic strains of S. aureus to cells from nonsecretors was significantly greater than to cells of secretors. Pre-treatment of epithelial cells with monoclonal anti-Lewis(a) or anti-type-1 precursor significantly reduced bacterial binding (P < 0.01); however, attachment of the bacteria correlated only with the amount of Lewis(a) antigen detected on the cells (P < 0.01). HEp-2 cells infected with RSV bound significantly more bacteria than uninfected cells. These findings are discussed in context of factors previously associated with SIDS (mother's smoking, bottle feeding and the prone sleeping position) and a hypothesis proposed to explain some cases of SIDS.

AB0 and Lewis blood groups in reactive arthritis

In this study we evaluated secretor status in patients with reactive arthritis. Previous evidence indicates that non-secretion of AB0 and Lewis blood group antigens to saliva and other secretions is associated with susceptibility to certain bacterial infections and certain diseases with suspected autoimmune etiology. Secretor status can be determined based on the Lewis phenotype. We studied AB0, Lewis and Rhesus blood groups of 54 patients with previous reactive arthritis, 26 of whom had uroarthritis and 28 of whom had arthritis after enteric infection. Furthermore, 25 patients with uncomplicated yersiniosis and 57 healthy controls were studied. We did not find any correlation between secretor status and reactive arthritis or gastroenteritis due to Yersinia. AB0 blood group antigen B appeared to be protective against uroarthritis.