Tolerogenic T cells, Th1/Th17 cytokines and TLR2/TLR4 expressing dendritic cells predominate the microenvironment within distinct oral mucosal sites.

BACKGROUND: Most local oral vaccine strategies use the sublingual region for drug application. Only little is known about the cytokine micromilieu, the nature of T cell subtypes and expression of target structures for adjuvants at different oral mucosal regions (OMR). However, targeting the optimal OMR might ensure highest efficiency of drug uptake and lowest risk for adverse effects. METHODS: Expression of TGF-ß1, IL10 as well as Th1, Th2 and Th17 cytokines and transcription factors was investigated at different OMR and skin by quantitative real-time PCR, immunohistochemistry or flow cytometry. RESULTS: Highest number of T cells was located in vestibular/buccal region (VBR). In contrast to skin (SK), OMR T cells produced TGF-ß1, IL-10, IFN-γ and IL-17. Significantly higher TGF-ß1 mRNA expression in the VBR compared with the sublingual region (SLR) and skin could be detected, while equal transcripts of IL-10 and regulatory T cell-associated transcription factor FoxP3 could be demonstrated. Expression of Th17-associated IL-17A, IL-17F, IL-22 and IL-26 mRNA could be demonstrated in VBR and SLR but not in SK. Interestingly, compared to SK, significantly higher expression of TGF-ß1 and IFN-γ could be detected in OMR. Moreover, expression of toll-like receptor (TLR) 2 and TLR4 was highest in VBR with significant expression on dendritic cells in OMR. CONCLUSION: From this data, we conclude that (i) VBR and SLR represent a protolerogenic micromilieu, (ii) both regions form a Th1 cytokine-predominated microenvironment, but also express mRNA for Th17 cytokines and (iii) TLRs detectable in VBR and SLR might serve as a target structures for adjuvants.

Distribution of Langerhans cells and mast cells within the human oral mucosa: new application sites of allergens in sublingual immunotherapy?

BACKGROUND: Sublingual immunotherapy (SLIT) represents an alternative to subcutaneous immunotherapy. While antigen-presenting cells such as Langerhans cells (LCs) are thought to contribute to the effectiveness of SLIT, mast cells (MCs) most likely account for adverse reactions such as sublingual edema. As little is known about LCs and MCs within the oral cavity, we investigated their distribution in search for mucosal sites with highest LCs and lowest MCs density. METHODS: Biopsies were taken simultaneously from human vestibulum, bucca, palatum, lingua, sublingua, gingiva, and skin. Immunohistochemistry and flow cytometry were used to detect MCs, LCs and high affinity receptor for IgE (FcepsilonRI) expression of LCs. Mixed lymphocyte reactions were performed to assess their stimulatory capacity. RESULTS: Highest density of MCs was detected within the gingiva, while the lowest density of MCs was found within the palatum and lingua. However, sublingual MCs were located within glands, which might explain swelling of sublingual caruncle in some SLIT patients. Highest density of LCs was detected within the vestibular region with lowest density in sublingual region. Highest expression of FcepsilonRI was detected on LCs within the vestibulum. Furthermore LCs from different regions displayed similar stimulatory capacity towards allogeneic T cells. CONCLUSIONS: In view of our data, different mucosal regions such as the vestibulum might represent alternative SLIT application sites with potent allergen uptake. Our data might serve as a basis for new application strategies for SLIT to enhance efficiency and reduce local adverse reactions.

Pathogenesis of heroin-associated glomerulonephritis. Correlation between the inflammatory activity and renal deposits of immunoglobulin and complement?

Renal specimens from 19 autopsies of persons known to be intravenous heroin-addicts and with severe lympho-monocytic glomerulonephritis were investigated to correlate the inflammatory activity and deposits of immunoglobulin and complement. In all sections, there were 10 or more LCA-positive cells/glomerulum, counted in 20 glomerula but only up to 3 LCA-positive cells in a control-group of 10 autopsied persons without drug addiction and any renal diseases. In some cases diffuse granular deposits of immunoglobulin were found together with deposits of Clq. Although these changes cannot be demonstrated in all cases, deposits of Clq point to an activation of the classical way of the complement binding system in heroin-associated glomerulonephritis. The underlying process, activation of the complement binding system by heroin/morphin itself and adulterants or by hepatitis B and C infection, which are frequent in heroin-addicts, is still unclear.