Matrix metalloproteinase-9 increases in the sputum from allergic occupational asthma patients after specific inhalation challenge.

BACKGROUND: Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) play a role in the pathogenesis of asthma. MMP-9 increases in the sputum of asthmatic patients after bronchial challenge with common allergens. We sought to assess whether a high-molecular-weight occupational allergen was able to induce changes in MMP-9 as well as in other MMPs and TIMPs in subjects with occupational asthma. METHODS: Ten patients underwent specific inhalation challenge (SIC) on 2 consecutive days. We monitored changes in lung function by measuring FEV(1) for 7 h. Induced sputum test was performed at 6 h after sham and flour challenge. The total and differential cell counts were analyzed. Levels of MMPs (specifically MMP-2, MMP-7, MMP-9 and MMP-13) were measured using Fluorokine® MultiAnalyte Profiling kits and a Luminex® Bioanalyzer, while levels of TIMP-1 and TIMP-2 were measured by ELISA. RESULTS: Flour challenge increased the percentage of eosinophils in sputum samples. Asthmatic reactions induced by flour were associated with a significant increase in the sputum level of MMP-9 (p = 0.05), but not in the levels of MMP-2, MMP-7, MMP-13, TIMP-1 and TIMP-2. Sputum levels of MMP-9 measured after flour challenge were nearly significantly correlated (r = 0.67; p = 0.06) with the maximal fall in FEV(1) observed during the asthmatic reaction, but they did not correlate with the number of neutrophils (r = 0.18; p = 0.7) and eosinophils (r = 0.55; p = 0.2). CONCLUSIONS: This study showed that MMP-9 increases in sputum samples from sensitized occupational asthma patients after SIC with flour.

Specific inhalation challenge with flour induced release of brain-derived neurotrophic factor in nasal fluid.

BACKGROUND: Neurotrophins may play a role in the pathophysiology of allergic occupational rhinitis (OR). We sought to investigate whether an immediate allergic reaction that induces nasal inflammation is also able to induce changes in levels of brain-derived neurotrophic factor (BDNF) in nasal lavage (NAL) fluid from patients with allergic OR. METHODS: Ten patients sensitized to flour underwent control and active specific inhalation challenge (SIC) on consecutive days. Nasal response to SIC was monitored with acoustic rhinometry and symptoms recording. NAL was performed before and 30 minutes, 6 hours, and 24 hours after control and active challenge for the assessment of levels of BDNF and inflammatory cells in NAL fluid. RESULTS: In contrast to control day, flour challenge induced immediate clinical reactions in all subjects. After flour challenge, a significant increase in levels of BDNF in NAL fluid was observed at 6 hours after challenge (p < 0.05). Also, a significant increase in the number of eosinophils in NAL fluid at 30 minutes (p < 0.01), 6 hours (p < 0.01), and 24 hours (p = 0.05) postchallenge was observed. Also, levels of BDNF in NAL fluid were significantly higher at 30 minutes after flour challenge (p = 0.02) in comparison to levels on the control day at the same postchallenge time. A marginally significant positive correlation between BDNF levels and eosinophil counts at 30 minutes (r = 0.60, p = 0.06) and at 6 hours (r = 0.50, p = 0.08) after flour challenge was noted. CONCLUSION: We showed that BDNF is released in nasal fluid after SIC with flour. Results support the suggestion that neurotrophins may play a role in the pathogenesis of allergic OR.

Prospective outcome assessment of occupational rhinitis after removal from exposure.

OBJECTIVE: To conduct a prospective evaluation of clinical and quality of life (QOL) outcomes of occupational rhinitis (OR) after cessation of exposure. METHODS: We assessed changes in nasal symptoms, disease-specific QOL, nasal patency, and nasal inflammation in 20 subjects with confirmed OR. Olfactory function was assessed cross-sectionally at follow-up. RESULTS: At follow-up, a significant decrease in the number of nasal symptoms and a significant improvement in QOL were observed. There were no significant differences in nasal patency outcomes. A not significant decrease in neutrophils number in nasal fluid and a significant decrease in macrophages were observed. As a group, study subjects showed a mild olfactory dysfunction at follow-up. CONCLUSIONS: We showed that cessation of exposure to causal agent improved QOL in patients with OR, leading to relief of rhinitis-associated symptoms and improvement in well-being.

Matrix metalloproteinases and tissue inhibitors of metalloproteinases in nasal lavage after an inhalation challenge with flour.

OBJECTIVES/HYPOTHESIS: The existence of nasal mucosa remodeling in allergic rhinitis is controversial. Few data are available on the dynamics of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in nasal fluid after an allergen challenge. We examined whether an immediate allergic reaction that induces nasal congestion and inflammation is able to also induce changes in remodeling parameters in nasal fluid. STUDY DESIGN: Controlled experimental study. METHODS: Ten patients with allergic occupational rhinitis due to flour underwent a control and active inhalation challenge with serial monitoring of nasal congestion and nasal symptoms with acoustic rhinometry and a visual analogue scale. Levels of remodeling markers (MMP-2, MMP-7, MMP-9, MMP-13, TIMP-1, TIMP-2) and inflammatory cells in nasal fluid were measured before the challenge and at 30 minutes, 6 hours, and 24 hours following the challenge. RESULTS: In contrast to the control challenge, the flour challenge induced nasal symptoms and significant decreases in nasal volume in all subjects. After the flour challenge, a significant increase in nasal levels of TIMP-2 and a nonsignificant increase in TIMP-1 levels were observed, whereas no significant changes in nasal levels of MMPs were documented. CONCLUSIONS: This study showed that after an inhalation challenge with an occupational allergen, the nasal mucosa displayed an imbalance in favor of TIMPs enzymes activity as compared to MMPs enzymes activity, represented in an increase in nasal levels of TIMP-2 during the course of the early reaction following the allergen challenge.

Proinflammatory mediators in nasal lavage of subjects with occupational rhinitis.

We sought to investigate the type and kinetics of late-phase nasal inflammatory response after nasal challenge with occupational allergens. Participants were 10 subjects experiencing work-related rhinitis symptoms who underwent specific inhalation challenge and tested positive for occupational rhinitis. During challenge, we monitored changes in inflammatory cells, eosinophil cationic protein, myeloperoxidase, and interleukin-8 in nasal lavage samples. The challenge with the active agent induced a significant increase in the percentage of eosinophils at 30 minutes as compared with prechallenge values (P = 0.04). A significant increase in eosinophil cationic protein levels after challenge with the control (P = 0.01) and active agent (P = 0.02) was observed in the late phase after challenge. No significant changes in nasal levels of neutrophils, myeloperoxidase, and interleukin-8 were observed on both control and active challenge days. Our results suggest a predominant nasal eosinophilic inflammatory response after occupational allergen challenge.

Reproducibility of acoustic rhinometry in the investigation of occupational rhinitis.

BACKGROUND: To diagnose occupational rhinitis, it is mandatory to conduct an objective assessment of changes in nasal patency during specific inhalation challenge (SIC). The reproducibility of acoustic rhinometry measurements in the setting of occupational challenges has never been examined. This study assessed the reproducibility of acoustic rhinometry during SIC investigation of occupational rhinitis. METHODS: Twenty-four subjects underwent acoustic rhinometry measurements during SIC investigation of occupational rhinitis. Subjects attended 3-6 days of SIC within a week by means of a realistic or closed-circuit apparatus methodology RESULTS: All of the within-day intraclass correlation coefficients (ICCs) for nasal volume (2-5 cm) and minimum cross-sectional area (MCA) based on a different number of measurements (2-7) were above 0.85; all of the coefficients of variation (CVs)for the same parameters were low (below 10%). The between-day CVs based on different numbers of SIC sessions ranged from 8.0 to 8.8% and from 6.8 to 8.8%for nasal volume and MCA, respectively. The between-day ICCs ranged from 0.80 to 0.88 and from 0.83 to 0.94 for nasal volume and MCA, respectively. CONCLUSION: Acoustic rhinometry showed good within- and between-day reproducibility and can be recommended for the objective monitoring of nasal patency during SIC investigating occupational rhinitis.

Diisocyanate antigen-stimulated monocyte chemoattractant protein-1 synthesis has greater test efficiency than specific antibodies for identification of diisocyanate asthma.

We previously reported that diisocyanate-human serum albumin (DIISO-HSA) stimulated production of monocyte chemoattractant protein-1 (MCP-1) by peripheral blood mononuclear cells is significantly associated with a clinical diagnosis of diisocyanate asthma (DA). Others have reported that antibodies for DIISO-HSA are specific but insensitive markers of DA. This study was performed to evaluate test characteristics of the in vitro MCP-1 assay compared with DIISO-HSA-specific immunoglobulin (Ig) G and IgE in identifying workers with DA. MCP-1 was quantitated in peripheral blood mononuclear cell supernatants 48 hours after incubation with DIISO-HSA antigens. Assay results were compared with outcomes of specific inhalation challenge (SIC) testing. Nineteen of 54 (35%) workers assayed for antibodies and MCP-1 stimulation had SIC-confirmed DA. Mean MCP-1 produced by SIC-positive workers was greater than SIC-negative workers (p < or = 0.001). Diagnostic sensitivity, specificity, and test efficiency for specific IgG were 47%, 74%, and 65%, respectively, and for specific IgE were 21%, 89%, and 65%, respectively. Sensitivity, specificity, and test efficiency of the MCP-1 test were 79%, 91%, and 87%, respectively. This study indicates that the MCP-1 stimulation assay has greater sensitivity and specificity than the specific antibody assays in correctly identifying DA.