Necrobacillosis in humans.

Necrobacillosis, often used synonymously with Lemierre's syndrome, is a form of abscess infection in the peritonsillar area associated with a thrombophlebitis and caused by the strict anaerobic species Fusobacterium necrophorum. The thrombosis formed affects the internal jugular vein, from which the bacteria are seeded out in the bloodstream and cause bacteremia. Septicemia is a common complication with an often fatal outcome. Necrobacillosis is very rare and is referred to as the 'forgotten disease'. It is probably frequently overlooked in clinical practice in its early and milder forms such as tonsillitis (sore throat) and peritonsillar abscess. F. necrophorum frequently participates in these infections and is thus suspected to have an etiological role in Lemierre's syndrome. Similarly, F. necrophorum seems to play an important role in noma (cancrum oris) and this disease is also included in the necrobacillosis complex. Diagnosis of infections of the necrobacillosis complex seeks to disclose F. necrophorum in swab samples or blood culture. The most commonly used therapy is metronidazole in combination with penicillin or amoxicillin. Clindamycin is also an option, especially in cases of penicillin allergy.

Pivotal advance: CD45RB glycosylation is specifically regulated during human peripheral B cell differentiation.

A screen of cell surface markers differentially expressed during peripheral B cell differentiation identified that the CD45RB epitope detected by the mAb MEM-55 was highly expressed on CD27(+) memory B cells and absent on CD27(-) naïve B cells. IgG(+)CD27(-) memory and a previously unacknowledged CD27(-) population in blood also expressed high levels of CD45RB(MEM55). Naïve and memory B cells from tonsils followed the pattern observed in blood, and CD38(high) B cells had a bimodal expression pattern when analyzed using flow cytometry. No CD38(high) GC B cells, however, expressed the CD45RB(MEM55) epitope when assayed using immunohistochemistry. Rather, CD38(high)CD45RB(MEM55high) B cells had a distinct cellular phenotype and were localized outside of GCs. CD45RB epitopes, detected by other antibody clones, were expressed at high levels through B cell differentiation, and no changes in splicing of the CD45RB exon were observed during B cell differentiation. Instead, B cells regulated their expression of the CD45RB(MEM55) epitope through site-specific modifications of an O-linked glycochain. CD4(+) T cells differentially spliced CD45 but did not vary the glycosylation of the CD45RB(MEM55) epitope, and CD8(+) cells modified CD45RB(MEM55) expression in a similar manner as B cells. Monocytes expressed the CD45RB exon but not the CD45RB(MEM55) epitope. As CD45 is a highly expressed tyrosine phosphatase that regulates antigen receptor signaling strength in lymphocytes, we conclude that regulated O-linked glycosylation of CD45RB can be used to follow B cell differentiation and that this regulation may be involved in fine-tuning antigen signaling in the cell.

Mucosal secretion changes during radiotherapy in the oral cavity.

Mucositis in the oral cavity is a serious complication during radiation therapy for head and neck cancer, causing local discomfort and pain. In severe cases, hospitalization and interruption of radiotherapy may be necessary. The pathogenesis of this mucositis is not clear. With the purpose of getting more understanding of the pathogenesis of the mucositis, we examined the mucosal secretion from ten patients during radiotherapy with an imprint technique. In the secretion we studied the cellular composition and cellular function. In eight of ten treated patients the numbers of granulocytes increased in the secretion after 2 weeks of radiation therapy. The granulocytes, however, did not show any signs of phagocytosis. The patients all developed mucositis. We propose that the granulocytes in the secretion might play an important role in the development of mucositis during radiotherapy.

Bacterial location in chronic sinusitis.

BACKGROUND: In chronic nonallergic sinusitis, it is often assumed that bacteria invade the sinus mucosa where the inflammatory condition begins and is maintained. However, the bacterial presence in a normal or moderately damaged epithelial layer has never been proved in biopsy studies. METHODS: In this study, mucosal samples from six consecutive patients with chronic sinusitis were examined. Transmission electron microscopy was used and the presence of bacterial invasion and formation of phagosomes containing bacteria as a marker of host response were studied. RESULTS: Phagocytosis of bacteria was observed in the sinus mucosa in samples from only one patient. In the other five patients, no signs of phagocytosis were seen. CONCLUSION: Based on these results, we concluded that in chronic sinusitis, bacterial invasion in sinus mucosa is not an obligatory phenomenon.

Deep neck space infections remain a surgical challenge. A study of 72 patients.

OBJECTIVE: The treatment of deep neck space infections (DNSIs) remains a clinical challenge and these infections are associated with significant risks of mortality. MATERIAL AND METHODS: We analyzed records over a 4.5-year period for all patients with DNSIs who required hospitalization. We recorded age, previous disease, delay in diagnosis, body temperature at admission, C-reactive protein level, X-ray results, location of DNSIs, origin of the infection, spread of infection, use of antibiotics, bacteriology, surgery and outcome. RESULTS: A total of 72 patients (average age 45 years) were included. The locations and spread of DNSIs were described in detail. The commonest origins of DNSIs were dental (n = 35) or salivary gland infections (n = 15). CONCLUSION: Continuous assessment of the patient using CT scans, fine-needle aspiration and physical examinations will determine if and when surgery is necessary. As a large number of DNSIs are of dental origin, it is of great importance that diagnosis and treatment be performed in close cooperation with dental surgeons.

Bacterial adherence to mucosal epithelium in the upper airways has less significance than believed.

BACKGROUND: Bacterial adherence to the upper airway epithelium is considered to be an important phenomenon in the pathogenesis of infections. However, the evidence for the hypothesis that bacterial adherence to mucosal epithelial cells has significance for pathogenesis of mucosal infections is based on studies using indirect techniques. We could find no biopsy studies with direct ocular observations of significant numbers of bacteria adhering to upper airway mucosal epithelial cells either in health or during disease. RESULTS: We studied specimens from healthy and infected tonsillar epithelium and specimens from the soft palate epithelium obtained by surgery. The specimens were examined by TEM. In the vast majority of specimens, we found no bacteria adhering to the epithelial cells in the mucosal line regardless of whether the patient was infected or not. Bacteria adhering to shed epithelial cells were seen in higher numbers. Furthermore, as bacteria are small compared to epithelial cells, we calculated the risk of overlooking every adhered bacteria in a section if bacterial adherence was such a significant phenomenon as earlier suggested. We found this risk to be very small. CONCLUSION: We conclude that bacterial adherence to mucosal surface epithelial cells is not a significant phenomenon, either in healthy mucosa in the upper airways or during infection. This is also in line with our earlier results, where we have shown that the site for the infectious process in pharyngotonsillitis is in the secretion on the tonsillar mucosal surface.

Neutrophils are hyperactive in recurrent tonsillitis.

The pathogenesis of recurrent tonsillitis has not been fully explored. Most studies in this field have focused on pathogenic bacteria whereas less research has been done concerning the host defense. In earlier studies it was shown that there is an active cellular defense in the tonsillar surface secretion, consisting of phagocytes, and therefore in this study the possibility that this defense is altered in patients with recurrent tonsillitis was explored. Neutrophils were obtained from tonsillar surface secretions in eight patients with recurrent tonsillitis and eight healthy volunteers and the capacity of the neutrophils to respond to chemotactic stimuli was examined in an in vitro system. A significantly higher fraction of the neutrophils obtained from the patients with recurrent tonsillitis responded to chemotactic stimuli compared to those obtained from the healthy volunteers. It is concluded that there is a hyperactive cellular defense in the tonsillar surface secretion in patients with recurrent tonsillitis. This finding and its significance in the pathogenesis of recurrent tonsillitis are discussed.