Precursor B Cells Increase in the Lung during Airway Allergic Inflammation: A Role for B Cell-Activating Factor.

BACKGROUND: B cells, key cells in allergic inflammation, differentiate in the bone marrow and their precursors include pro-B, pre-B and immature B cells. Eosinophil progenitor cells increase in the lung after allergen exposure. However, the existence and possible role of B cell precursors in the lung during allergic inflammation remains elusive. METHODS: A BALB/c mouse model of allergic airway inflammation was utilized to perform phenotypic and quantification analyses of pro-B and pre-B cells in the lung by flow cytometry. B cell maturation factors IL-7 and B cell-activating factor (BAFF) and their receptors (CD127 and BAFFR, BCMA, TACI, respectively) were also evaluated in the lung and serum. The effect of anti-BAFF treatment was investigated both in vivo (i.p. administration of BAFF-R-Ig fusion protein) and in vitro (colony forming cell assay). Finally, BAFF levels were examined in the bronchoalveolar lavage (BAL) of asthmatic patients and healthy controls. RESULTS: Precursor pro and pre-B cells increase in the lung after allergen exposure, proliferate in the lung tissue in vivo, express markers of chemotaxis (CCR10 and CXCR4) and co-stimulation (CD40, CD86) and are resistant to apoptosis (Bax). Precursor B cells express receptors for BAFF at baseline, while after allergen challenge both their ligand BAFF and the BCMA receptor expression increases in B cell precursors. Blocking BAFFR in the lung in vivo decreases eosinophils and proliferating precursor B cells. Blocking BAFFR in bone marrow cultures in vitro reduces pre-B colony formation units. BAFF is increased in the BAL of severe asthmatics. CONCLUSION: Our data support the concept of a BAFF-mediated role for B cell precursors in allergic airway inflammation.

Analysis of oral yeast microflora in patients with oral squamous cell carcinoma.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is the most common form of oral cancer, in this study, the association between OSCC and oral yeast carriage was investigated. FINDINGS: 20 patients having OSCC as well as 40 healthy controls were tested for the presence of yeasts in the oral cavity. Fungal burdens were examined by colony forming unit determinations, while the different yeast genera in patient samples were identified by matrix-associated laser desorption/ionization-time of flight-mass spectrometry. We found that the level of oral yeast carriage was significantly higher in patients with OSCC that was accompanied by a higher diversity of yeasts in the oral cavity of these patients. We also examined the extracellular enzyme production of isolated Candida spp.; however, we found that there was no association between the lipase/protease producing capacity of Candida strains and the higher colonisation rate of neoplastic epithelium. CONCLUSIONS: In conclusion, our results corroborate the findings of previous studies regarding the association between oral yeast carriage and epithelial carcinoma.