The Stonehouse study: secretor status and carriage of Neisseria species

Hereditary gingival fibromatosis

Hereditary gingival fibromatosis (HGF) is a rare condition that can occur as an isolated disease, chromosomal abnormality, or as part of a number of syndromes. The gingival enlargement in HGF can be so severe that it can cover the crowns of teeth completely, causing severe functional derangement and facial disfigurement. Through review of literature revealed that HGF is usually an autosomal dominant condition, however the recessive forms are also reported. The hyperplastic gingiva is firm on palpation and has normal color with abundant stippling on the adjacent gingiva. The buccal and lingual gingiva may be involved in both the mandible and maxilla. The degrees of gingival enlargement show both intra- and interindividual variations. Here, an interesting case report of massive HGF has been presented.

Idiopathic gingival hyperplasia

Gingival hyperplasia is a rare condition but it is important for cosmetic and mechanic reasons and because of its potential as an indicator of systemic disease. Gingival fibromatosis may exist as an isolated abnormality or as part of a syndrome. In this article a case that was diagnosed clinically and histologically as idiopathic gingival fibromatosis is presented. Patient with gingival hyperplasia should be examined to exclude other reasons to determine the idiopathic gingival fibromatosis or not. Treatment is not required in all cases of idiopathic gingival hyperplasia. Surgical excision is indicated if mechanical problems exist. Recurrence has not been reported.

The incidence and mortality for meningococcal disease associated with area deprivation: an ecological study of hospital episode statistics

AIMS

To determine whether incidence, mortality, and case fatality for meningococcal disease (MD) differs by area deprivation, and if this has changed over time.

METHODS

The population of children aged less than 5 years with MD was analysed as quintiles of area deprivation scores over two time periods, 1995-99 and 1991-94. Annual age standardised rates were calculated and the association between incidence, mortality, and area deprivation quintiles assessed using Poisson regression and the risk ratios determined. Case fatality was calculated from the odds ratio of mortality by area deprivation score for the two time periods.

RESULTS

There were 10,524 cases of MD and 441 deaths (4.2%). Incidence rates were higher for 1995-99 (45.4 per 100,000) compared to 1991-94 (27.4 per 100,000). Mortality rates remained stable over time, indicating a decline in risk of death of around 40%. The incidence rates for the most deprived quintile were around twice those for the most affluent quintile, but this gradient declined over time. A threefold gradient was seen for mortality rates across the top and bottom quintiles, which was constant over time. The odds of mortality did not show a linear pattern, with mortality being lowest in the first and highest in the second and fifth area deprivation quintiles.

CONCLUSIONS

These data show that MD incidence and mortality are socially patterned. The determinants of case fatality are more complex and require further investigation.

Genetic aspects of dental disorders

This paper reviews past and present applications of quantitative and molecular genetics to dental disorders. Examples are given relating to craniofacial development (including malocclusion), oral supporting tissues (including periodontal diseases) and dental hard tissues (including defects of enamel and dentine as well as dental caries). Future developments and applications to clinical dentistry are discussed. Early investigations confirmed genetic bases to dental caries, periodontal diseases and malocclusion, but research findings have had little impact on clinical practice. The complex multifactorial aetiologies of these conditions, together with methodological problems, have limited progress until recently. Present studies are clarifying previously unrecognized genetic and phenotypic heterogeneities and attempting to unravel the complex interactions between genes and environment by applying new statistical modelling approaches to twin and family data. Linkage studies using highly polymorphic DNA markers are providing a means of locating candidate genes, including quantitative trait loci (QTL). In future, as knowledge increases; it should be possible to implement preventive strategies for those genetically-predisposed individuals who are identified to be at risk.

Assessment of the interleukin 1 gene cluster and other candidate gene polymorphisms in host susceptibility to tuberculosis

SETTING

A study of tuberculosis cases and healthy blood donor controls from the Western Region of The Gambia, West Africa.

OBJECTIVE

To investigate the potential role of candidate gene polymorphisms in host susceptibility to tuberculosis.

DESIGN

Single base change polymorphisms in interleukin 1 beta (IL1 beta), interleukin 10 (IL10) and fucosyltransferase-2 (FUT-2), microsatellite polymorphisms in interleukin 1 alpha (IL1 alpha) and IL10 and a minisatellite polymorphism in interleukin 1 receptor antagonist (IL1RA) were typed in over 400 tuberculosis cases and 400 healthy blood donor controls.

RESULTS

IL1 gene cluster polymorphisms (IL1RA and possibly IL1 alpha) showed marginally significant association with tuberculosis. In particular IL1RA allele 2 heterozygotes were less frequent among tuberculosis cases than controls (P = 0.03). IL1 beta, IL10 and FUT-2 polymorphisms were not associated with tuberculosis.

CONCLUSION

Genetic susceptibility to tuberculosis among Gambians may be partly determined by genes in the IL1 gene cluster on chromosome 2. Further association studies will be required on other population groups to confirm whether these results are of biological significance.

Secretor status and human leucocyte antigens in coeliac disease

BACKGROUND

The ability to secrete blood group antigens into body fluids and secretions is controlled by a single gene on chromosome 19. By means of erythrocyte Lewis (Le) antigen phenotype secretor status can be inferred. An increase prevalence of non-secretors of blood group antigens among coeliac patients has recently been described.

METHODS

Blood was collected from 112 coeliac patients and 103 controls and tested for secretor status. Secretor status was correlated with human leucocyte antigens (HLA) in coeliac patients, thus evaluating a proposed interaction of susceptibility genes--that is, the secretor gene on chromosome 19 and HLA-linked genes on chromosome 6. Case notes for coeliacs were reviewed with regard to clinical outcome.

RESULTS

Of 112 coeliacs who had either Le(a) or Le(b) antigens, 36 (32%) were non-secretors Le(a+, b-), compared with 27% (28) of 103 disease-free controls (P = 0.313). Recessive Lewis phenotype Le(a-, b-) was found in 9% of coeliacs versus 2% of controls. Prevalence of HLA-A1, B8, DR3, and DQ2 was unrelated to secretor status in coeliac versus patients. An increased prevalence of complications and coeliac-associated abnormalities was found in the non-secreting and recessive coeliac groups.

CONCLUSIONS

This study shows no firm relationship between the non-secretor state and coeliac disease, nor any difference in the distribution of HLA markers among secretor and non-secretor coeliacs. It is unlikely, therefore, that the secretor gene is the much sought-after second coeliac gene.

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.

Factors affecting carriage of Neisseria meningitidis among Greek military recruits

Greek military recruits (993) were examined for carriage of meningococci during July 1990. Blood, saliva and throat swab specimens were obtained and each recruit answered a questionnaire providing information on age, education (a measure of socioeconomic level), place of residence, smoking habits and recent infections. The overall carriage rate was 25% but differed between the two camps: 79/432 (18%) in Camp A and 168/561 (30%) in Camp B (P less than 0.0005). In Camp B, there were significantly higher proportions of recruits who were non-secretors (P less than 0.0005), and/or heavy smokers (P less than 0.0005). They were also younger (less than 19 years old) (P less than 0.001), and on the whole had fewer years of education (P less than 0.0005). By univariate analysis, carriage was significantly associated with smoking. By multiple logistic regression analysis, carriage was associated with smoking (P less than 0.001), age (P less than 0.01) and the camp in which the recruits were based (P less than 0.01). Among recruits in Camp B, 15/38 (40%) of those with recent viral infections were carriers compared with 30% for the camp in general.

Association between secretor status and respiratory viral illness

OBJECTIVE

To determine whether non-secretion of blood group antigens is associated with respiratory virus diseases.

DESIGN

Study of secretor status in patients with respiratory virus diseases determined by an enzyme linked immunosorbent assay (ELISA) developed to identify Lewis (Le) blood group antigen phenotypes (Le(a) non-secretor; Le(b) secretor).

SUBJECTS

Patients aged 1 month to 90 years in hospital with respiratory virus diseases (584 nasal specimens).

MAIN OUTCOME MEASURES

Criteria for validation of ELISA (congruence between results on ELISA testing of 1155 saliva samples from a previous study and previously established results on haemagglutination inhibition (HAI) testing, proportions of Le(a), Le(b), and Le- phenotypes in 872 samples of nasal washings from a previous study compared with the normal population). Secretor status of patients determined by ELISA and viruses isolated.

RESULTS

Agreement between HAI and ELISA for 1155 saliva samples was 97%. Lewis antigens were detected by ELISA in 854 (97.9%) of nasal washings (Le(a) 233 (26.7%), Le(b) 621 (71.2%), and Le- 18 (2.1%)) in proportions predicted for a northern European population. Secretors were significantly overrepresented among patients from whom influenza viruses A and B (55/64, 86%; p less than 0.025), rhinoviruses (63/72, 88%; p less than 0.01), respiratory syncytial virus (97/109, 89%; p less than 0.0005), and echoviruses (44/44, p less than 0.0005) had been isolated compared with the distribution of secretors in the local population.

CONCLUSION

Secretion of blood group antigens is associated with respiratory virus diseases.

Genetic approaches in the study of periodontal diseases

Periodontal diseases are essentially infectious in origin, their outcome depending on interaction between the pathogenic challenge and host response. Host genotype has been implicated in certain of the more unusual forms, but together these account for only a small proportion of periodontal patients. Nevertheless, the genes for these rarer conditions, some of which have already been located and/or cloned, are of considerable importance, since they may ultimately provide clues leading to a better understanding of the whole spectrum of periodontal disease. For the majority of periodontal patients, although inherited susceptibility is suspected, evidence of a significant genetic component is scanty. The priority here is therefore to establish the existence of contributing genes. This may be possible by using approaches designed to minimise the confounding effect of environmental variation that has probably been a source of confusion in the past.

Identification of a UK outbreak strain of Neisseria meningitidis with a DNA probe

To investigate the epidemiology of meningococcal disease, a specific DNA probe pUS210 (carrying insert DNA which is repeated in the meningococcal genome) was isolated. The ability of this probe to hydridise with multiple polymorphic fragments in Southern blots was exploited to examine genetic relations within strains. Two geographically distinct foci of prolonged meningococcal disease (Gloucester and Plymouth, UK) are due to a clonal population of virulent strains that are distinct from those found elsewhere in the UK.

Sexual reproduction as an adaptation to resist parasites (a review)

Darwinian theory has yet to explain adequately the fact of sex. If males provide little or no aid to offspring, a high (up to 2-fold) extra average fitness has to emerge as a property of a sexual parentage if sex is to be stable. The advantage must presumably come from recombination but has been hard to identify. It may well lie in the necessity to recombine defenses to defeat numerous parasites. A model demonstrating this works best for contesting hosts whose defense polymorphisms are constrained to low mutation rates. A review of the literature shows that the predictions of parasite coevolution fit well with the known ecology of sex. Moreover, parasite coevolution is superior to previous models of the evolution of sex by supporting the stability of sex under the following challenging conditions: very low fecundity, realistic patterns of genotype fitness and changing environment, and frequent mutation to parthenogenesis, even while sex pays the full 2-fold cost.

Secretor status, smoking and carriage of Neisseria meningitidis

A survey of ABO blood groups, secretor status and smoking habits among 389 students and staff of a school in which there was an outbreak of meningococcal disease found no difference in the distribution of the ABO blood groups but a significantly higher proportion of non-secretors (37.6%) in the population examined compared with that reported for previous surveys of the neighbouring population in Glasgow (26.2%) (P less than 0.0005). There was also a significantly higher proportion of non-secretors among carriers of meningococci (47%) compared with non-carriers (32%). Increased carriage of meningococci among non-secretors might contribute to the increased susceptibility of individuals with this genetic characteristic to meningococcal disease observed in previous studies. Although passive exposure to cigarette smoke has been associated with meningococcal disease, there was no association between passive smoking and carriage. There was, however, a significant association between active smoking and carriage.