Supraesophageal reflux: validation of a symptom questionnaire.

OBJECTIVE: To develop and validate a questionnaire for supraesophageal manifestations of reflux (SER) that will facilitate its study in clinical and research settings. STUDY DESIGN: The Supraesophageal Reflux Questionnaire (SERQ) and previously validated Reflux Symptom Index (RSI) were subjected to multiple types of validity testing, including content validity, concurrent validity, reproducibility, and predictive validity. RESULTS: The concurrent validity and reproducibility of both instruments was good to excellent for most items tested. The predictive validity of the SERQ was superior to the RSI when it included the covariates of history of sinusitis, use of over-the-counter antacid medications, age, gender, and body mass index. CONCLUSIONS: The SERQ will serve as both a useful clinical and research tool by offering not only SER symptom information, like the RSI, but also information about the patient's medical history and medication usage that will facilitate use of the SERQ in research protocols. EBM RATING: B-2b.

Effects of interferon-gamma and tumour necrosis factor-alpha on CD95/Fas ligand-mediated apoptosis in human blood eosinophils.

Many cells, including eosinophils, express CD95 (Fas), a surface receptor that mediates apoptosis when ligated by specific antibodies or its natural ligand, Fas ligand (FasL). As apoptosis may play an important role in the regulation of tissue eosinophilia, factors that modulate eosinophil sensitivity to apoptosis are of great interest. It has previously been shown that interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha) together increase CD95 surface expression on eosinophils. However, the functional consequences of this increase in CD95 expression have not been demonstrated in detail. We therefore investigated whether the increase in CD95 expression mediated by IFN-gamma/TNF-alpha indeed translates into increased, FasL-mediated apoptosis of eosinophils. For this purpose, purified eosinophils from normal donors were incubated with different concentrations of FasL and induction of apoptosis was assessed by annexin-V/propidium iodide assay. Unlike Jurkat cells, which became apoptotic within 2 h after incubation with FasL, an increase in eosinophil apoptosis could first be dedicated after 6 h incubation with FasL. Prestimulation with IFN-gamma/TNF-alpha for 24 h significantly enhanced FasL-induced apoptosis in eosinophils. This increase in CD95/FasL-mediated apoptosis was correlated with an IFN-gamma/TNF-alpha-mediated increase in CD95 expression. From these findings we conclude that the combination of IFN-gamma and TNF-alpha enhances CD95 expression, which results in an increase in FasL-mediated apoptosis of eosinophils in vitro.

Differential regulation of CD95 (Fas/APO-1) expression in human blood eosinophils.

CD95 (Fas, APO-1) is a cell surface receptor expressed on many cells including eosinophils which mediates apoptosis when ligated by agonistic antibodies or its natural ligand FasL. Since inhibition of apoptosis may play an important role in controlling tissue eosinophilia, we investigated the expression of CD95 on purified peripheral blood eosinophils from normal donors. Freshly isolated eosinophils expressed CD95 on the cell surface as well as CD95-specific mRNA at low levels which did not change during 24-h culture. Incubation of eosinophils with IL-3, IL-5 and granulocyte-macrophage colony-stimulating factor (GM-CSF) did not modulate the basal expression of CD95. IFN-gamma as well as TNF-alpha, however, induced a significant, dose- and time-dependent increase in CD95 mRNA and cell surface expression as measured by reverse transcription-PCR and flow cytometry. Co-stimulation with IFN-gamma and TNF-alpha had synergistic effects on the CD95 surface expression on eosinophils. Addition of IL-3, IL-5 or GM-CSF to IFN-gamma- and TNF-alpha-stimulated eosinophils caused in a reduction of CD95 expression. Functional activity for CD95 following incubation with IFN-gamma and TNF-alpha was demonstrated by increased apoptosis in response to cross-linking with FasL. From these data, we conclude that IFN-gamma and TNF-alpha can up-regulate cell surface expression of CD95 on eosinophils, which leads to an increased susceptibility of eosinophils to Fas-mediated apoptosis. Thus, our results suggest that receptors involved in eosinophil apoptosis can be regulated by antagonistic cytokines.