Dysbiosis of Oral Microbiota Associated with Palmoplantar Pustulosis.

BACKGROUND: Dysbiosis of oral microbiota is implicated not only in oral inflammatory lesions, but also in a variety of extraoral diseases. The etiology of palmoplantar pustulosis (PPP) remains unclear; however, it has been suggested that chronic inflammation caused by periodontopathic bacterial infection may play a role. OBJECTIVES/METHODS: To determine whether patients with PPP have altered diversity and composition of oral microbiota, we conducted the 16S rDNA analysis using saliva samples collected from 21 outpatients with PPP and 10 healthy individuals. RESULTS: We found that the proportion of bacteria in the phylum Proteobacteria was significantly lower in PPP patients (p = 0.025). At the genus level, patients with PPP had a significantly lower abundance of Neisseria (p = 0.014), which best accounted for the observed decrease in Proteobacteria. We also identified multiple minor genera and species that were represented at a significantly higher level in the PPP group, several of which have been associated with periodontal diseases. CONCLUSION: Our results suggest a possible link between PPP and dysbiosis of oral microbiota, particularly the lower abundance of Neisseria, the most predominant genus of Proteobacteria in healthy oral microbiota. Probiotics that improves oral dysbiosis may be beneficial for patients with PPP as an adjunctive therapy.

Higher Prevalence of Nickel and Palladium Hypersensitivity in Patients with Ulcerative Colitis.

BACKGROUND: The etiology of ulcerative colitis (UC) remains elusive even though many genetic and environmental pathogenic factors have been reported. Aberrant inflammatory responses mediated by specific subsets of T cells have been observed in ulcerative lesions of UC patients. OBJECTIVES: To elucidate the involvement of a delayed-type hypersensitivity reaction in UC, we focused on dental metal hypersensitivity, a T cell-mediated, delayed-type allergic reaction that causes oral contact mucositis and systemic cutaneous inflammation. METHOD: We recruited 65 Japanese UC patients and 22 healthy controls (HC) and used the in vitro lymphocyte stimulation test to quantify their sensitivity to zinc, gold, nickel, and palladium - the metals that have been widely used in dentistry. All subjects were users of metallic dental implants and/or prostheses containing zinc, gold, nickel, and/or palladium as major constituents. RESULTS: Sixty percent of the UC patients were hypersensitive to at least one metal species, whereas 32% of the HC were hypersensitive to only a single metal species. The overall incidence of metal hypersensitivity was significantly higher for UC patients than for HC. Furthermore, a significantly greater proportion of UC patients were hypersensitive to nickel or palladium. The severity of the sensitivity to nickel and palladium was also significantly greater for UC patients than for HC. CONCLUSIONS: This pilot study demonstrates that UC patients have a significantly higher incidence of hypersensitivity to nickel and palladium, suggesting the possible involvement of dental metal hypersensitivity in UC pathogenesis.

Higher incidence of zinc and nickel hypersensitivity in patients with irritable bowel syndrome.

INTRODUCTION: The etiology of irritable bowel syndrome (IBS) remains elusive even though several genetic and environmental pathogenic factors have been reported. IBS is considered to be a functional disorder without any detectable lesions in the patient's bowel. However, many studies have demonstrated that a subset of IBS patients have low-grade inflammation and aberrant T-cell activation in their intestinal mucosa. To elucidate the immune mechanism underlying the mucosal inflammation in IBS, we focused on dental metal hypersensitivity, a T cell-mediated, delayed-type allergic reaction that causes oral contact mucositis and systemic cutaneous inflammation. METHODS: We recruited 147 Japanese IBS patients and 22 healthy controls (HCs). The subjects underwent the in vitro lymphocyte stimulation test to quantify their sensitivity to zinc, gold, nickel, and palladium, the metals that have been commonly used in dentistry. RESULTS: A total of 56.5% of the IBS patients were hypersensitive to at least one metal species, whereas 31.8% of HC were hypersensitive to only a single metal species. The overall incidence of metal hypersensitivity was significantly higher for IBS patients than for HC. Furthermore, a significantly higher proportion of IBS patients were hypersensitive to zinc and/or nickel. The severity of the sensitivity to zinc and nickel was also significantly greater for IBS patients than for HC. There was no significant difference in the sensitization rates and the sensitivity among the IBS subtypes. CONCLUSIONS: This pilot study demonstrates that IBS patients have a significantly higher prevalence of hypersensitivity to zinc and nickel, suggesting the possible involvement of dental metal hypersensitivity in IBS pathogenesis in a subset of patients.