Dilated intercellular space in chronic laryngitis and gastro-oesophageal reflux disease: at baseline and post-lansoprazole therapy.

BACKGROUND: Dilation of intercellular spaces is reported to be an early morphological marker in gastro-oesophageal reflux. It remains unknown if this marker is useful in diagnosing reflux-related chronic laryngitis. AIM: To determine histopathology and electron microscopic changes in oesophageal and laryngeal epithelium in chronic laryngitis. METHODS: In this prospective blinded study, we enrolled 53 participants: 15 controls, 20 patients with GERD and 18 patients with chronic laryngitis. The latter two groups were subsequently treated with lansoprazole 30 mg bid for 12-weeks. Baseline and postacid suppressive therapy biopsies were obtained from distal oesophagus and laryngeal postcricoid areas. Biopsy specimens were evaluated for histopathology and dilated intercellular space changes. RESULTS: There was no significant increase in oesophageal or laryngeal epithelium intercellular spaces among GERD or laryngitis patients compared with controls at baseline or postacid suppressive therapy. Only patients with GERD had significantly (P = 0.03) higher proportion of moderate-to-severe oesophageal spongiosis and basal cell hyperplasia, which normalized postacid suppressive therapy. CONCLUSIONS: There was no increase in the width of intercellular spaces in the oesophagus or larynx in GERD or chronic laryngitis at baseline or postacid suppressive therapy. Our findings question the uniform presence of dilated intercellular space in patients with GERD.

Secretion of interleukin-1 receptor antagonist from human mast cells after immunoglobulin E-mediated activation and after segmental antigen challenge.

Mast cells produce substances with antiinflammatory properties in addition to their capacity to release proinflammatory mediators. To further probe the antiinflammatory aspect of mast-cell function we investigated the ability of human mast cells (huMCs) to produce interleukin (IL)-1 receptor antagonist (IL-1ra) in response to high-affinity Fc receptor for immunoglobulin E (Fcalpha RI) aggregation, and examined IL-1ra in bronchoalveolar lavage fluid (BALF) to determine whether it might be of mast-cell origin. Using a ribonuclease protection assay, flow cytometry, and enzyme-linked immunosorbent assay (ELISA), IL-1ra message and protein were found to be constitutively expressed in cultured huMCs. Upon stimulation through Fcalpha RI, IL-1ra message was upregulated in huMCs and IL-1ra protein secreted from cultured huMCs and isolated human lung mast cells. By immunoblot analysis, huMCs were found to produce the 17-kD form of IL-1ra and the presence of IL-1ra in human lung mast cells was confirmed by immunohistochemistry. In BALF obtained from allergic asthmatic subjects, IL-1ra production increased after specific antigen challenge, with the 17-kD isoform of IL-1ra predominating. These findings demonstrate that huMCs produce and release IL-1ra after Fcalpha RI aggregation, which may contribute to a local inhibition of IL-1-dependent effects on inflammation in the lung.

Further characterization of FcgammaRII and FcgammaRIII expression by cultured human mast cells.

BACKGROUND: We have reported that resting human mast cells exhibit minimal expression for FcgammaRI, and that interferon-gamma will upregulate this expression. The expression of FcgammaRII and FcgammaRIII by human mast cells remains to be fully examined. METHODS: To investigate FcgammaRII and FcgammaRIII expression, we determined mRNA and protein expression of FcgammaRII and FcgammaRIII in human peripheral blood CD34+ derived cultured mast cells by RT-PCR and flow cytometry. The expression of FcgammaRII and FcgammaRIII in intact and permeabilized mast cells was also compared. We measured histamine release to monitor mast cell degranulation following cross-linking of FcgammaRII. RESULTS: We found by RT-PCR that resting human mast cells exhibit mRNA for FcgammaRIIA, FcgammaRIIb1, FcgammaRIIb2 and FcgammaRIII but not FcgammaRIIC. FACS analysis of Fcgamma receptors in intact versus permeabilized mast cells showed expression of FcgammaRII to be 42.2 +/- 3.9% and this was unchanged by permeabilization. FcgammaRIII protein expression was minimal and this was also unchanged by permeabilization. Aggregation of FcgammaRII on human mast cells led to no significant degranulation as evidenced by histamine release. CONCLUSIONS: In addition to FcgammaRI expression, human mast cells express FcgammaRIIA, FcgammaRIIb1, FcgammaRIIb2 and FcgammaRIII mRNA, and significant surface expression of FcgammaRII. Aggregation of FcgammaRII on cultured human mast cells in this model was not followed by histamine release.

A comparison of mediators released or generated by IFN-gamma-treated human mast cells following aggregation of Fc gamma RI or Fc epsilon RI.

The high affinity receptor for IgG (Fc gamma RI, CD64) is expressed on human mast cells, where it is up-regulated by IFN-gamma and, thus, may allow mast cells to be recruited through IgG-dependent mechanisms in IFN-gamma-rich tissue inflammation. However, the mediators produced by human mast cells after aggregation of Fc gamma RI are incompletely described, and it is unknown whether these mediators are distinct from those produced after activation of human mast cells via Fc epsilon RI. Thus, we investigated the release of histamine and arachidonic acid metabolites and examined the chemokine and cytokine mRNA profiles of IFN-gamma-treated cultured human mast cells after Fc gamma RI or Fc epsilon RI aggregation. Aggregation of Fc gamma RI resulted in histamine release and PGD(2) and LTC(4) generation. These responses were qualitatively indistinguishable from responses stimulated via Fc epsilon RI. Aggregation of Fc epsilon RI or Fc gamma RI led to an induction or accumulation of 22 cytokine and chemokine mRNAs. Among them, seven cytokines (TNF-alpha, IL-1beta, IL-5, IL-6, IL-13, IL-1R antagonist, and GM-CSF) were significantly up-regulated via aggregation of Fc gamma RI compared with Fc epsilon RI. TNF-alpha mRNA data were confirmed by quantitative RT-PCR and ELISA. Furthermore, we confirmed histamine and TNF-alpha data using IFN-gamma-treated purified human lung mast cells. Thus, aggregation of Fc gamma RI on mast cells led to up-regulation and/or release of three important classes of mediators: biogenic amines, lipid mediators, and cytokines. Some cytokines, such as TNF-alpha, were released and generated to a greater degree after Fc gamma RI aggregation, suggesting that selected biologic responses of mast cells may be preferentially generated through Fc gamma RI in an IFN-gamma-rich environment.