Effect of bovine milk fermented with Lactobacillus rhamnosus L8020 on periodontal disease in individuals with intellectual disability: a randomized clinical trial.

OBJECTIVE: Studies on the oral health of individuals with intellectual disability (ID) have identified problems that include a high prevalence of periodontal disease. The use of probiotics to treat periodontal disease has been the focus of considerable research, and bovine milk fermented with Lactobacillus rhamnosus L8020 (L8020 yogurt) has been shown to reduce the oral prevalence of four periodontal pathogens. The aim of this randomized, double-blind, placebo-controlled trial was to compare the effects of L8020 yogurt (test group) with those of placebo yogurt (placebo group) on the papillary-marginal-attached (PMA) index, gingival index (GI), and probing depth (PD) in 23 individuals with ID. METHODOLOGY: All patients were required to consume the allocated yogurt after breakfast for 90 days. PMA index and GI scores as well as PDs were assessed before the start of yogurt consumption (baseline), after 45 and 90 days of consumption, and 30 days after the cessation of consumption. Student's t-test, Mann-Whitney U test or Fisher's exact test was used for inter-group comparisons, and the mixed effect model of repeated measurements was used for data analysis. RESULTS: The decrease in PMA index score was significantly greater in the test group than in the placebo group (p<0.001). The GI score also decreased during the study, with a tendency for greater decrease in the test group. Furthermore, decreases in PD between baseline, 45 and 90 days tended to be greater in the test group than in the placebo group. CONCLUSION: These results suggest that regular consumption of bovine milk fermented with L. rhamnosus L8020 can lower the risk of periodontal disease in individuals with ID.

Effect of bovine milk fermented with Lactobacillus rhamnosus L8020 on periodontal disease in individuals with intellectual disability: a randomized clinical trial

Abstract Studies on the oral health of individuals with intellectual disability (ID) have identified problems that include a high prevalence of periodontal disease. The use of probiotics to treat periodontal disease has been the focus of considerable research, and bovine milk fermented with Lactobacillus rhamnosus L8020 (L8020 yogurt) has been shown to reduce the oral prevalence of four periodontal pathogens. Objective The aim of this randomized, double-blind, placebo-controlled trial was to compare the effects of L8020 yogurt (test group) with those of placebo yogurt (placebo group) on the papillary-marginal-attached (PMA) index, gingival index (GI), and probing depth (PD) in 23 individuals with ID. Methodology All patients were required to consume the allocated yogurt after breakfast for 90 days. PMA index and GI scores as well as PDs were assessed before the start of yogurt consumption (baseline), after 45 and 90 days of consumption, and 30 days after the cessation of consumption. Student's t-test, Mann-Whitney U test or Fisher's exact test was used for inter-group comparisons, and the mixed effect model of repeated measurements was used for data analysis. Results The decrease in PMA index score was significantly greater in the test group than in the placebo group (p<0.001). The GI score also decreased during the study, with a tendency for greater decrease in the test group. Furthermore, decreases in PD between baseline, 45 and 90 days tended to be greater in the test group than in the placebo group. Conclusion These results suggest that regular consumption of bovine milk fermented with L. rhamnosus L8020 can lower the risk of periodontal disease in individuals with ID.

General anesthetic actions on GABAA receptors in vivo are reduced in phospholipase C-related catalytically inactive protein knockout mice.

PURPOSE: The aim of this study was to investigate the action of general anesthetics in phospholipase C-related catalytically inactive protein (PRIP)-knockout (KO) mice that alter GABAA receptor signaling. METHODS: PRIP regulates the intracellular trafficking of ß subunit-containing GABAA receptors in vitro. In this study, we examined the effects of intravenous anesthetics, propofol and etomidate that act via ß subunit-containing GABAA receptors, in wild-type and Prip-KO mice. Mice were intraperitoneally injected with a drug, and a loss of righting reflex (LORR) assay and an electroencephalogram analysis were performed. RESULTS: The cell surface expression of GABAA receptor ß3 subunit detected by immunoblotting was decreased in Prip-knockout brain compared with that in wild-type brain without changing the expression of other GABAA receptor subunits. Propofol-treated Prip-KO mice exhibited significantly shorter duration of LORR and had lower total anesthetic score than wild-type mice in the LORR assay. The average duration of sleep time in an electroencephalogram analysis was shorter in propofol-treated Prip-KO mice than in wild-type mice. The hypnotic action of etomidate was also reduced in Prip-KO mice. However, ketamine, an NMDA receptor antagonist, had similar effects in the two genotypes. CONCLUSION: PRIP regulates the cell surface expression of the GABAA receptor ß3 subunit and modulates general anesthetic action in vivo. Elucidation of the involved regulatory mechanisms of GABAA receptor-dependent signaling would inform the development of safer anesthetic therapies for clinical applications.

Comparative proteome analysis of wild-type and klotho-knockout mouse kidneys using a combination of MALDI-IMS and LC-MS/MS.

PURPOSE: Mutation of the klotho gene in mice elicits a syndrome resembling accelerated human aging. However, there is limited evidence for the role of Klotho in the kidney. We conducted a comparative proteome analysis of wild-type (WT) and klotho-knockout (kl-/- ) mouse kidneys to identify proteins involved in Klotho deficiency. EXPERIMENTAL DESIGN: MALDI imaging MS (MALDI-IMS) of frozen kidney sections from 7-wk-old male WT and kl-/- mice was used to determine genotype-specific differences in the MS distribution. Proteins uniquely distributed in kl-/- kidneys were identified by subsequent analysis of adjacent trypsinized sections by MALDI-IMS in combination with LC-MS/MS. Immunohistochemistry and western blotting were adopted in qualitative and quantitation analysis. RESULTS: Ninety-seven and 69 proteins identified by LC-MS/MS were matched to the MALDI-IMS spectra in WT and kl-/- mouse kidneys, respectively. Among protein types matched, nucleic acid binding proteins were most abundant, followed by enzymes. We identified secretogranin-1 (SCG1), which was predominately distributed in the glomeruli and renal tubules of kl-/- mouse kidneys. Immunohistochemistry for SCG1 mirrored images of MALDI-IMS. CONCLUSIONS: SCG1 may be a candidate protein involved in Klotho deficiency. Although further research is needed to investigate the role of SCG1 in the kidney, we show the usefulness of MALDI-IMS combined with LC-MS/MS.

Five-year longitudinal study of dental caries risk associated with Streptococcus mutans and Streptococcus sobrinus in individuals with intellectual disabilities.

Streptococcus mutans (S. mutans) and Streptococcus sobrinus (S. sobrinus) are important etiologic agents in human dental caries. Using quantitative real-time polymerase chain reaction assays for the presence of those strains, we examined 145 outpatients with intellectual disability (ID), calculated the proportion of each of these strains to total bacteria, and compared dental caries incidence over 5 years. Plaque samples were collected from all erupted tooth sites, and dental examinations were performed annually to determine numbers of decayed, missing, and filled teeth (DMFT score; World Health Organization caries diagnostic criteria). Elevated DMFT scores were calculated as ∆DMFT, and sites of newly affected caries (∆SNAC) were identified. Sixty-six patients had both strains. The proportion of S. mutans to total bacteria was moderately correlated with DMFT in year 2, ∆DMFT in years 2 and 5, and ∆SNAC in years 2 and 5 (correlation coefficient = 0.470, P < 0.001), while the proportion of S. sobrinus to total bacteria was moderately correlated with DMFT in years 2 and 5, ∆DMFT in years 1, 2, and 5, and ∆SNAC in years 2 and 5 (correlation coefficient = 0.695, P < 0.001). Individuals with ID who harbored both bacterial strains had a higher risk of dental caries and a significantly higher proportion of S. sobrinus to total bacteria.

Imaging and mapping of mouse bone using MALDI-imaging mass spectrometry.

Matrix-assisted laser desorption/ionization-imaging mass spectrometry (MALDI-IMS) is an advanced method used globally to analyze the distribution of biomolecules on tissue cryosections without any probes. In bones, however, hydroxyapatite crystals make it difficult to determine the distribution of biomolecules using MALDI-IMS. Additionally, there is limited information regarding the use of this method to analyze bone tissues. To determine whether MALDI-IMS analysis of bone tissues can facilitate comprehensive mapping of biomolecules in mouse bone, we first dissected femurs and tibiae from 8-week-old male mice and characterized the quality of multiple fixation and decalcification methods for preparation of the samples. Cryosections were mounted on indium tin oxide-coated glass slides, dried, and then a matrix solution was sprayed on the tissue surface. Images were acquired using an iMScope at a mass-to-charge range of 100-1000. Hematoxylin-eosin, Alcian blue, Azan, and periodic acid-Schiff staining of adjacent sections was used to evaluate histological and histochemical features. Among the various fixation and decalcification conditions, sections from trichloroacetic acid-treated samples were most suitable to examine both histology and comprehensive MS images. However, histotypic MS signals were detected in all sections. In addition to the MS images, phosphocholine was identified as a candidate metabolite. These results indicate successful detection of biomolecules in bone using MALDI-IMS. Although analytical procedures and compositional adjustment regarding the performance of the device still require further development, IMS appears to be a powerful tool to determine the distribution of biomolecules in bone tissues.

Longitudinal study of dental caries incidence associated with Streptococcus mutans and Streptococcus sobrinus in patients with intellectual disabilities.

BACKGROUND: Mutans streptococci (Streptococcus mutans and S. sobrinus) are considered to be major etiologic agents of dental caries. Using a polymerase chain reaction method, we detected those bacteria from 145 outpatients (6-30 years old) with intellectual disabilities (ID) and their presence was compared with the incidence of dental caries. METHODS: Plaque samples were collected from all erupted tooth sites in subjects with a sterile toothbrush. A dental examination was performed to determine the number of decayed and filled teeth (DFT score) in permanent dentition using the WHO caries diagnostic criteria. A Mann-Whitney U-test was employed to compare the caries scores between combinations of the bacteria, and with a Wilcoxon rank test used to compare caries scores between the baseline and after 1 year. RESULTS: Among all subjects, S. mutans and S. sobrinus were possessed by 78.7 and 83.5%, respectively, while 13.1% were positive for S. mutans alone, 17.9% for S. sobrinus alone, and 65.6% for both organisms, with 3.4% were negative for both. The mean DFT score of subjects positive for both S. mutans and S. sobrinus at after 1 year was significantly higher than that of those positive for S. mutans alone (P < 0.01). The increase in caries increment was also significantly greater in subjects with both bacteria detected (P < 0.001). CONCLUSION: Our results indicate that patients with ID harboring both S. mutans and S. sobrinus have a significantly higher incidence of dental caries than those with S. mutans alone.

Prevalence of drug-resistant opportunistic microorganisms in oral cavity after treatment for oral cancer.

Drug-resistant opportunistic infections may cause health problems in immunocompromised hosts. Representative microorganisms in opportunistic infections of the oral cavity are Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. We investigated the prevalence of drug-resistant opportunistic microorganisms in elderly adults receiving follow-up examinations after primary treatment of oral cancer. Oral microorganisms were collected from patients satisfactorily treated for oral cancer (defined as good outcomes to date) and a group of healthy adults (controls). After identification of microorganisms, the prevalence of drug-resistant microorganisms was studied. Pulsed-field gel electrophoresis (PFGE) and staphylococcal cassette chromosome mec (SCCmec) typing were also performed for methicillin-resistant S aureus (MRSA). Statistical analysis revealed no significant differences in the prevalences of the three microorganisms between the groups. Surprisingly, 69.2% of S aureus isolates showed oxacillin resistance, suggesting that MRSA colonization is increasing among older Japanese. These MRSA isolates possessed SCCmec types II and IV but no representative toxin genes. Our results indicate that a basic infection control strategy, including standard precautions against MRSA, is important for elderly adults, particularly after treatment for oral cancer.

Prevalence of Porphyromonas gingivalis fimA genotypes in Japanese children.

Porphyromonas gingivalis FimA fimbriae have been classified into 6 genotypes (types I-V and Ib) based on the diversity of the fimA genes encoding the fimbrial subunits. We investigated the prevalence of fimA genotype in Japanese children. Dental plaque specimens were obtained from 400 subjects (age; 2 to 15 years), including 134 with healthy gingiva, 239 with gingivitis and 27 with periodontitis, and then analyzed by polymerase chain reaction. P. gingivalis was detected in 1.5%, 10.0% and 29.6% of these subjects, respectively. Significant differences were observed with regard to P. gingivalis infection among the groups [chi-squared analysis: gingivitis vs. healthy, P < 0.01, odds ratio (OR) = 7.4; periodontitis vs. healthy, P < 0.001, OR = 27.8]. In P. gingivalis-positive subjects with periodontitis, the most prevalent fimA types were type Ib/type II combination (37.5%) and type IV (37.5%), followed by type II (25.0%), while type IV (33.3%) and type II (29.2%) were most often detected in those with gingivitis. Our results suggest that the presence of P. gingivalis is associated with periodontal diseases, and that the type II, IV and Ib/II combination are the most common among fimA genotypes.

Caries prevalence associated with Streptococcus mutans and Streptococcus sobrinus in Japanese schoolchildren.

BACKGROUND: Streptococcus mutans and Streptococcus sobrinus are known to be associated with dental caries in humans. AIM: We used a polymerase chain reaction method to detect S. mutans and S. sobrinus in 128 Japanese schoolchildren and then compared their presence with the dental caries experience. DESIGN: Plaque samples were collected from all erupted tooth sites with a sterile toothbrush, and dental examinations were performed to determine the numbers of decayed and filled teeth in primary (dft) and permanent (DFT) dentition using the WHO caries diagnostic criteria. Fisher's PLSD test was employed to compare caries scores between combinations of the detected bacteria. RESULTS: Streptococcus mutans and S. sobrinus were present in 38.3% and 68.0%, respectively, whereas 14.8% were positive for S. mutans alone, 44.5% for S. sobrinus alone, and 23.5% for both S. mutans and S. sobrinus, with 17.2% negative for both. The DFT, dft, and total (DFT + dft) scores for subjects positive for both S. mutans and S. sobrinus were significantly higher than those positive for S. mutans alone (P < 0.05, in triplicate). CONCLUSION: These results suggest that schoolchildren harbouring both S. mutans and S. sobrinus have a significant higher dental caries experience in both permanent and primary teeth as compared to those with S. mutans alone.

PRECEDE-PROCEED model modification in community-based oral health promotion by using the linear structural relations programme.

PURPOSE: The PRECEDE-PROCEED (P-P) model is a framework for designing health education/promotion programmes. While the P-P model has been used to design community-based oral health programmes, outcome assessments of the model are seldom reported. The aim of the present study was to explore whether pathways in the P-P model accurately reflect the current status of environmental/behavioural assessment in a Japanese community and to examine whether using the linear structural relations (LISREL) programme would improve the model. MATERIALS AND METHODS: In a community health centre in Japan, a questionnaire with 29 items regarding oral health was distributed to 824 mothers with 3-year-old children. The items were compiled into eight variables that were tested using the LISREL programme. Goodness-of-fit index (GFI), adjusted goodness-of-fit index (AGFI) and root mean square error of approximation (RMSEA) were statistically analysed before and after P-P model modification. RESULTS: The GFI, AGFI and RMSEA were 0.913, 0.776 and 0.161 before, and 0.975, 0.939 and 0.075 after P-P model modification, respectively. Indirect effects on the quality of life from the predisposing, reinforcing and enabling factors became stronger than those in the initial P-P model. The overall fit of the modified P-P model was significantly better than that of the P-P model without modification, which did not accurately reflect the status of environmental/behavioural assessment in the community. CONCLUSIONS: The modified P-P model reflected the current status of environmental/behavioural assessment in the community. Health education models should be tested rigorously to ensure that they fit the reality of people's behaviour.

Late Established Mutans Streptococci in Children over 3 Years Old.

Acquisition of mutans streptococci has been reported to most commonly occur at approximately 26 months of age. In the present study, we detected Streptococcus mutans and S. sobrinus using polymerase chain reaction (PCR) assays in children, then re-examined the subjects to determine the time of acquisition of these bacteria over a 1-year period. The subjects were 57 children ranging in age from 3 to 5 years old, each with primary dentition. Plaque samples were collected from all erupted tooth sites using a sterile toothbrush. PCR assays were performed to detect the targeted mutans streptococci at the beginning of the study (baseline) and after 1 year. At the baseline examination, the prevalence of S. mutans and S. sobrinus was 61.4% and 54.4%, respectively, in all subjects, of whom 14 (24.6%) were positive for S. mutans alone, 10 (17.5%) for S. sobrinus alone, and 21 (36.8%) for both S. mutans and S. sobrinus, with 12 (21.1%) negative for both. After 1 year, 4 of 22 (18.2%) subjects newly had acquired S. mutans and 15 of 26 (57.7%) had aquired S. sobrinus, while 5 (8.8%) remained negative for both bacteria. The age of the first positive S. mutans finding ranged from 49 to 71 months, while that for S. sobrinus ranged from 49 to 81 months old. Our results suggest that S. sobrinus becomes established later than S. mutans in the oral cavities of children over the age of 3 years old.

Simultaneous interrelationship between the oral health behavior and oral health status of mothers and their children.

The purpose of this study was to examine the simultaneous interrelationships of oral health behavior and oral health between mothers and their children using the linear structural relations (LISREL) program. The subjects comprised 117 pairs of mothers and their children aged between 8 and 11 years. Dental status was expressed as DMFT. The Oral Rating Index (ORI) for mothers and ORI for children (ORI-C) were used as measures of gingival health. Hiroshima University Dental Behavioral Inventory (HU-DBI) was used for the assessment of mothers' oral health behavior. HU-DBI had a direct positive relationship to ORI, a direct negative relationship to DFT, and a direct positive association with ORI-C. Toothbrushing had a direct negative relationship to ORI-C. The hypothesized model was found to be closely consistent with the data. These results indicate that the periodontal health status of mothers is directly related to the oral health status of their children, and that toothbrushing by children is directly related to their gingival health.

Teenagers' oral health attitudes and behavior in Japan: comparison by sex and age group.

We investigated sex and age group differences in attitudes to oral health among school-age children using an Oral Self-Care Appraisal (OSCA) to systematically determine changes in oral health knowledge, attitude, and behavior across developmental stages. The subjects (n = 1584) were stratified after random sampling so that each school grade analyzed contained 88 boys and 88 girls. Factor analysis was undertaken to identify a set of underlying factors, with 10 factors considered in the cross-sectional study. Our results showed that the factors toothbrushing, persistence, and sociability were more predominant in primary school children than in junior high and senior high school students. Furthermore, postponement of visiting the dentist and resignation to one's own dental cavities became more predominant in proportion to the level of school education. Girls had significantly higher scores than boys for desire to improve oral care, dental anxiety, dependency on snacks, toothbrushing, concern over number of cavities, and sociability. Together, the results indicated that the oral health care behavior of girls was better than that of boys, and that the tendency to postpone visiting the dentist and resignation to one's own dental cavities increased markedly with age.

Subgingival distribution of Campylobacter rectus and Tannerella forsythensis in healthy children with primary dentition.

OBJECTIVE: It is important to know how many subgingival plaque samples should be assayed from a child to ascertain infection with a periodontal pathogen. Plaque samples from several sites may fail to detect some important bacteria if only a limited number of gingival sites are sampled. The purpose of this study was to evaluate the detection of periodontal pathogens in a large number of subgingival sites in the same children in order to determine the number of samples necessary. METHODS: Ten children, aged 4-6 years, with complete primary dentition were enrolled in this study. Plaque samples from the mesio-buccal aspect of each erupted tooth were first collected by gently inserting a sterile paper point for 10s. Purified genomic DNA from all plaque samples was prepared for polymerase chain reaction. The primers for species-specific 16S ribosomal RNA sequence were selected as the target sequence. Standard strains of Campylobacter rectus and Tannerella forsythensis (formerly Bacteroides forsythus) were used as control strains. RESULTS: All subjects were found positive for C. rectus and T. forsythensis with the mean of positive sites at 17.6 +/- 2.4 (range: 12-20 sites) for C. rectus and 9.3 +/- 5.0 (range: 1-19) for T. forsythensis. The mean number of positive sites was 1.7 +/- 0.8 for C. rectus and 6.5 +/- 4.9 for T. forsythensis, with a confidence ratio of 95%. CONCLUSIONS: We concluded that two or more random sites for C. rectus and seven or more random sites for T. forsythensis from children to detect those bacteria at 95% probability.

Longitudinal study of dental caries incidence associated with Streptococcus mutans and Streptococcus sobrinus in pre-school children.

Streptococcus mutans and Streptococcus sobrinus are known to be associated with the development of dental caries. In this study these bacteria were detected in pre-school children (each with primary dentition, age range 3-5 years, n = 60) using a PCR method, and then their presence was compared with the incidence of dental caries over a 1-year period. Plaque samples were collected from all erupted tooth sites using a sterile toothbrush. Dental examinations at the beginning of the study (baseline) and after 1 year were also performed to determine decayed, missing, filled teeth (dmft) scores using WHO caries diagnostic criteria. The prevalences of S. mutans and S. sobrinus across all the subjects were 61.7% and 56.6%, respectively; 13 subjects (21.7%) were positive for S. mutans alone, 10 (16.6%) were positive for S. sobrinus alone and 24 (40.0%) were positive for both S. mutans and S. sobrinus, whereas 13 (21.7%) were negative for both S. mutans and S. sobrinus. dmft scores of subjects positive for both S. mutans and S. sobrinus at baseline and after 1 year were significantly higher than of those positive for S. mutans alone at the same stages (P < 0.01 and P < 0.001, respectively). The caries incremental increase was also significantly greater in those with both bacteria detected (P < 0.05). Our results indicate that pre-school children harbouring both S. mutans and S. sobrinus have a significantly higher incidence of dental caries than those with S. mutans alone.

Intra-familial distribution of nine putative periodontopathogens in dental plaque samples analyzed by PCR.

It is of great importance to understand the distribution of periodontopathogens within family members when considering the risk of periodontitis in children. The purpose of this study was to investigate the distribution of periodontopathogens among family members. We used the polymerase chain reaction method to test 4,8, and 7 probands with healthy gingiva, gingivitis, and periodontitis, respectively, and their 60 immediate family members. Plaque samples were collected from all erupted teeth sites using a sterile toothbrush. In 161 of the 165 positive cases, if a child harbored one of the periodontopathogens then at least one of the parents was also positive for the same bacterium. The prevalence of parent-child co-infection was 42.9% for Actinobacillus actinomycetemcomitans, 21.4% for Porphyromonas gingivalis, 29.2% for Treponema denticola, 59.5% for Tannerella forsythensis (Bacteroides forsythus) and 16.7% for Prevotella intermedia. Our results indicate that parents could be an important source of periodontopathogens for the colonization that occurs in their children.

Oral findings in Noonan syndrome: report of a case.

Oral findings in a case of Noonan syndrome in an 8-year-old Japanese male are reported. Examination of the patient revealed a narrow, high-arched palate and an anterior open bite. Cephalometric measurements showed a wide gonial angle, a large mandibular plane angle, a large Y-axis and long facial height. It is suggested that the patient had a skeletal open-bite malocclusion, which included an abnormal swallowing habit.

Localized aggressive periodontitis in primary dentition: a case report.

BACKGROUND: A 5-year-old Japanese boy presented with persistent gingival inflammation and severe mobility of the right lower primary incisors. Due to severe alveolar bone loss and a deep periodontal pocket (5 mm), the incisors were extracted at the second visit. METHODS: Clinical, radiographic, histological, and microbiological examinations were carried out. Then, the polymerase chain reaction (PCR) technique was employed to detect specific periodontal pathogens. The chemotactic activity of polymorphonuclear neutrophils was also measured. RESULTS: Tannerella, Capnocytophaga, Fusobacterium, and Eikenella sp. were recovered from the subgingival microflora around the right lower incisors, while A. actinomycetemcomitans, Tannerella forsythensis (formerly Bacteroides forsythus), Prevotella nigrescens, Campylobacter rectus, and Capnocytophaga gingivalis were detected using the PCR method. Further chemotaxis assay revealed that neutrophil function was depressed compared with that of healthy controls. CONCLUSIONS: Although inflammation remained around the right primary second molars, the bone loss was controlled by periodic professional mechanical teeth cleaning (PMTC), subgingival irrigation, and local antibiotic application. The probing depths of all teeth, including permanent incisors and molars, were within 2.5 mm.

Microbiological, immunological and genetic factors in family members with periodontitis as a manifestation of systemic disease, associated with hematological disorders.

The microflora, immunological profiles of host defence functions, and human leukocyte antigen (HLA) findings are reported for a mother, son and daughter who were diagnosed as having 'periodontitis as a manifestation of systemic diseases, associated with hematological disorders'. Examinations were made of the bacterial flora from the periodontal pocket, neutrophil chemotaxis, neutrophil phagocytosis, and the genotypes (DQB1) and serotypes (DR locus) of HLA class II antigens. Phenotypic analyses of the peripheral lymphocytes were also conducted. The subgingival microflora from the mother was dominated by Gram-negative rods, especially Porphyromonas endodontalis, Prevotella intermedia/Prevotella nigrescens and Fusobacterium nucleatum. Subgingival microflora samples from the son and daughter were dominated by Gram-positive cocci and Gram-positive rods. Through the use of polymerase chain reaction, Campylobacter rectus and Capnocytophaga gingivalis were detected in all subjects, whereas Porphyromonas gingivalis, P. intermedia, and Treponema denticola were not detected in any subjects. All three subjects showed a remarkable level of depressed neutrophil chemotaxis to N-formyl-methionyl-leucyl-phenylalanine, although their phagocyte function levels were normal, in comparison to healthy control subjects. Each subject had the same genotype, HLA-DQB1*0601, while the mother had HLA-DR2 and HLA-DR8, and the son and daughter had HLA-DR2 only. In summary, the members of this family showed a similar predisposition to periodontitis with regard to certain host defence functions. It is suggested that the depressed neutrophil chemotaxis that was identified here could be a significant risk factor for periodontitis in this family.