Spontaneous Regression of Swollen Submandibular Glands in IgG4-Related Disease.

BACKGROUND: IgG4-related disease is a new clinical entity frequently associated with swelling of the submandibular glands (SMGs). The long-term outcome of SMG swelling without steroid therapy remains unknown. OBJECTIVE: To examine whether swollen SMGs spontaneously regress without steroid therapy in the context of IgG4-related disease and to identify biomarkers that can predict the spontaneous regression of SMG swelling. METHODS: The SMG volume of 49 patients diagnosed with IgG4-related disease was calculated by measuring the axial and coronal planes of computed tomography scans. The change in SMG volume over time was measured and examined by treatment regimen, clinical data, and serum complement level. RESULTS: We found 28 of 49 (57%) IgG4-related disease patients to have swollen SMGs, with 15 of 20 (75%) of the swollen SMGs regressing without steroid therapy. The time required for the SMGs swelling to regress was significantly shorter in the steroid therapy group than in the no-steroid therapy group. Serum complement components at the initial visit were significantly lower in the regressed SMG group than in the nonregressed SMG group. CONCLUSION: We observed 75% of swollen SMGs spontaneously regressed in patients with IgG4-related disease. The time required for the swollen SMGs to regress was longer in patients without steroid therapy than in those with steroid therapy. Serum complement level could be used as a predictor for the spontaneous regression of swollen SMGs in patients with IgG4-related disease.

Genetic mutation analysis of the malignant transformation of sinonasal inverted papilloma by targeted amplicon sequencing.

BACKGROUND: The mechanism underlying the malignant transformation of inverted papilloma (IP) has not yet been elucidated. METHODS: To clarify the genes responsible for the malignant transformation, we analyzed 10 cases of IP, 8 of IP with dysplasia, and 11 of squamous cell carcinoma (SCC) by targeted amplicon sequencing. RESULTS: The number of mutant genes increased in the order of IP < dysplasia < SCC. Significant differences were observed in the mutation rates of three genes (KRAS, APC and STK11) in particular. TP53 was altered frequently in each group and might be involved in malignant transformation based on to the site of the mutation. A comparison of the genetic variants by region of IP tissue among patients with IP alone, and those with dysplasia or SCC revealed significant differences in the mutation rate of the KRAS gene. CONCLUSION: Identification of genetic mutations in KRAS is effective for predicting the malignant transformation of IP.

Elevated Level of Myeloperoxidase-Deoxyribonucleic Acid Complex in the Middle Ear Fluid Obtained From Patients With Otitis Media Associated With Antineutrophil Cytoplasmic Antibody-associated Vasculitis.

OBJECTIVE: The purpose was to explore the presence of myeloperoxidase (MPO)-deoxyribonucleic acid (DNA) complex as a surrogate marker of neutrophil extracellular traps (NETs) in the middle ear fluid, and to clarify the correlation between its quantifiable level and hearing outcome in patients with otitis media associated with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). STUDY DESIGN: Prospective study. SETTING: Tertiary referral center. PATIENTS: Nine AAV patients presenting with otitis media. INTERVENTION: Collection of the fluid samples from middle ear. MAIN OUTCOME MEASURE: The quantifiable levels of MPO-DNA complex using an enzyme-linked immunosorbent assay. RESULTS: The quantifiable levels of MPO-DNA complex in patients with AAV were significantly higher than those in controls (p < 0.001). In particular, both ANCA-positive and -negative cases indicated higher levels of MPO-DNA complex compared with the controls (p = 0.004 and p = 0.006, respectively). The significant negative correlations were observed between the level of MPO-DNA complex and the functional hearing values for air (r = -0.82, p = 0.009) and bone conduction (r = -0.73, p = 0.028), respectively. CONCLUSION: This analysis is the first to reveal the presence of elevated levels of MPO-DNA complex in the middle ear fluid, suggesting the pathogenic role of NETs in otitis media associated with AAV. NETs may be a valuable biomarker for use in clinical decision-making and predicting hearing outcome, regardless of ANCA status.

Role of microRNA-296-3p in the malignant transformation of sinonasal inverted papilloma.

Inverted papilloma (IP) is a benign tumor occurring in the nasal cavity and paranasal sinuses. It is reported that 5-15% of IPs undergo malignant transformation into squamous cell carcinoma (SCC), and the role of microRNAs (miRNA/miR) in this process remains to be elucidated. In the present study, whole miRNA profiles using samples of IP and SCC were investigated, in order to detect the function of miRNA in the carcinogenesis of IP. Samples from IPs (n=5) and SCC lesions (n=5), which arose from IPs, were used for miRNA analysis. A total of 200 miRNAs exhibited a >2-fold differential expression between IP and SCC. miR-296-3p was markedly upregulated in SCC with a 23-fold difference. Computational analysis indicated that miR-296-3p targeted PTEN, which regulates the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway and PTEN is involved in the carcinogenesis of SCC. miR-296-3p directly regulated PTEN expression in head and neck cancer cells, with PTEN protein levels decreased in 4/19 the SCCs (21.0%), as compared with those in the IPs (76.4%). Positive p21 staining was observed in 64.7% of IPs; this was a significantly increased rate compared with that for SCCs (26.3%, P=0.0086). The results of the present study indicated that there were marked changes in the miRNA expression signature during the malignant transition. miR-296-3p may serve an important role in the malignant transformation of IPs via the regulation of PTEN, combined with the subsequent inhibition of the PI3K/Akt signaling pathway, and may be a novel agent for cancer prevention.

Otologic and Rhinologic Manifestations of Eosinophilic Granulomatosis with Polyangiitis.

BACKGROUND: Eosinophilic granulomatosis with polyangiitis (EGPA) is a systemic autoimmune disease that manifests as asthma, recurrent sinusitis and peripheral eosinophilia. In this study, we investigated the clinical features of the ear and nasal manifestations of EGPA in comparison with those of granulomatosis with polyangiitis (GPA). MATERIALS AND METHODS: Twenty-one patients diagnosed with EGPA were studied. The frequency of otologic manifestations, the degree of hearing loss and the frequency of nasal symptoms were assessed. The onset of ear symptoms, sinusitis and asthma in patients with EGPA were also examined. RESULTS: Eleven patients (52.4%) with EGPA demonstrated otologic symptoms. The EGPA patients commonly presented mild-to-moderate mixed or sensorineural hearing loss. The pattern of hearing loss was mainly flat, and all but 1 patient achieved complete remission from their hearing impairments. Eighteen patients (85.7%) with EGPA demonstrated nasal symptoms. Patients with EGPA showed a significantly higher incidence of nasal polyps than did those with GPA. The median Lund and Mackey scoring system score was 13.7 for patients with EGPA, and ethmoid sinus shadows were more severe than those of the maxillary sinus. Most ear symptoms associated with EGPA were observed after definitive diagnosis, although sinusitis and asthma tended to manifest themselves before diagnosis. There were significant differences between the onset of ear symptoms and those of asthma and sinusitis. CONCLUSION: As over 80% of patients with EGPA had nasal symptoms and over half had ear symptoms, otolaryngologists should be aware of this disease. Recognition of the characteristic ear and nasal symptoms are thought to be particularly important to obtain an early diagnosis of EGPA.

TRIM39 negatively regulates the NFκB-mediated signaling pathway through stabilization of Cactin.

NFκB is one of the central regulators of cell survival, immunity, inflammation, carcinogenesis and organogenesis. The activation of NFκB is strictly regulated by several posttranslational modifications including phosphorylation, neddylation and ubiquitination. Several types of ubiquitination play important roles in multi-step regulations of the NFκB pathway. Some of the tripartite motif-containing (TRIM) proteins functioning as E3 ubiquitin ligases are known to regulate various biological processes such as inflammatory signaling pathways. One of the TRIM family proteins, TRIM39, for which the gene has single nucleotide polymorphisms, has been identified as one of the genetic factors in Behcet's disease. However, the role of TRIM39 in inflammatory signaling had not been fully elucidated. In this study, to elucidate the function of TRIM39 in inflammatory signaling, we performed yeast two-hybrid screening using TRIM39 as a bait and identified Cactin, which has been reported to inhibit NFκB- and TLR-mediated transcriptions. We show that TRIM39 stabilizes Cactin protein and that Cactin is upregulated after TNFα stimulation. TRIM39 knockdown also causes activation of the NFκB signal. These findings suggest that TRIM39 negatively regulates the NFκB signal in collaboration with Cactin induced by inflammatory stimulants such as TNFα.

Oxidative stress regulates IL-4 gene expression in mast cells through the reduction of histone deacetylase.

OBJECTIVE: Many proinflammatory cytokines are regulated by the acetylation and deacetylation of the core histone. Since dysregulation of T helper 2 cytokine production is a key in the pathogenesis of allergic diseases, we examined the role of histone deacetylase (HDAC) on interleukin (IL)-4 gene expression in mast cells. We also examined whether oxidative stress has any impact on HDAC activity. STUDY DESIGN: In vitro study. SETTING: Academic research laboratory. METHODS: An IgE-sensitized mast cell line (RBL-2H3 cells) was treated with varying concentrations of the HDAC inhibitors trichostatin A (TSA) and H2O2 and stimulated with antigens. The amount of IL-4 gene expression was quantified by real-time polymerase chain reaction. Quantitative measurement of IL-4 in the cell supernatant was performed using enzyme-linked immunosorbent assay. Moreover, HDAC activity was measured with the use of a nonisotopic assay that utilized an HDAC Fluorescent Activity Assay Kit. RESULTS: IL-4 mRNA expression was induced by antigens in IgE-sensitized RBL-2H3 cells. Pretreatment with TSA and H2O2 enhanced IL-4 mRNA expression up to 5-fold in a dose-dependent manner. Furthermore, HDAC activity in RBL-2H3 cells was reduced after treatment with H2O2. CONCLUSION: Our results suggest that oxidative stress may up-regulate IL-4 gene expression in mast cells via a decrease in HDAC activity.

Otologic manifestations of immunoglobulin G4-related disease.

OBJECTIVE: Immunoglobulin (Ig) G4-related disease is systemic, and it has been reported that patients with IgG4-related disease complain of symptoms involving numerous organs. However, there are few reports concerning the otologic manifestations of IgG4-related disease. The purpose of this study is to investigate the clinical features of the otologic manifestations in IgG4-related disease. METHODS: We recruited 39 consecutive patients diagnosed with IgG4-related disease. Otologic symptoms, laboratory data, and audiogram findings were retrospectively examined. Mucosal tissues from the inferior turbinate were obtained from subjects before treatment. The serum IgG4 and eosinophil levels together with clinical features were analyzed. RESULTS: Five of the 39 cases had some otologic symptoms. Otitis media with effusion was present in 2 patients. Sensorineural hearing loss was also present in I patient. Eosinophilic otitis media was present in 2 patients with bilateral rhinosinusitis and bronchial asthma, and elevated serum eosinophil levels. Oral prednisolone was effective in the treatment of IgG4-related disease. CONCLUSION: We revealed a new clinical entity associated with the otologic manifestations of IgG4-related disease.

Prediction of the attachment site of sinonasal inverted papillomas by preoperative imaging.

OBJECTIVE: Accurate preoperative identification of the attachment site is the key to the successful surgical management of sinonasal inverted papillomas (IPs). This study investigated the value of preoperative imaging to identify the attachment sites of IPs. METHODS: We analyzed I 0 consecutive patients with pathologically proven IPs. Two radiologists predicted the attachment sites of IPs from computed tomography (CT), 3.0 Tesla magnetic resonance imaging (3.0T MRI), 1.5T MRI, and CT plus 3.0T MRI. The actual tumor attachment sites were confirmed via pathological examination of specimens and compared with the predicted sites. RESULTS: Computed tomography showed the highest sensitivity (P < .0001), although both MRI formats showed greater specificity (P < .0001). The sensitivity of MRI plus CT was equal to that of CT and better than that of MRI (P < .0001), whereas its specificity was better than that of CT (P < .0001) and comparable to that of MRI. Prediction using 3.0T MRI appeared slightly superior to that using 1.5T MRI in terms of sensitivity and specificity, although the differences were not significant. CONCLUSION: Computed tomography and MRI had different features for prediction of sinonasal IP attachment sites. Preoperative CT plus MRI provided more useful information than CT or MRI alone.

Sputum plasminogen activator inhibitor-1 elevation by oxidative stress-dependent nuclear factor-κB activation in COPD.

BACKGROUND: Plasminogen activator inhibitor-1 (PAI-1) is an important regulator of fibrinolysis at sites of vascular injury and thrombus formation. Recently, sputum PAI-1 was reported to be elevated in COPD. However, the mechanism of PAI-1 elevation in COPD has yet to be clarified. Here, we show that PAI-1 elevation in COPD is closely associated with oxidative stress-induced nuclear factor κB (NF-κB) activation. METHODS: Patients and control subjects were recruited from the outpatient department of Royal Brompton Hospital, local general practice, and the National Heart and Lung Institute. Sputum samples were obtained, and sputum sample processing was performed to obtain sputum supernatants and sputum macrophages. RESULTS: The mean PAI-1 level in COPD sputum (1.92 ± 3.11 ng/mL, n = 32) was higher than that of both age-matched smokers without COPD (0.48 ± 0.63 ng/mL, n = 11) and healthy nonsmokers (0.55 ± 1.11 ng/mL, n = 9). Sputum PAI-1 significantly correlated with sputum malondialdehyde (MDA) in COPD (r = 0.59, P < .001). In addition, NF-κB activity in sputum macrophages (three control and seven COPD subjects) significantly correlated with both sputum PAI-1 (r = 0.72, P < .05) and sputum MDA (r = 0.78, P < .01). An in vitro study showed that both hydrogen peroxide and cigarette smoke-conditioned medium induced PAI-1 production in A549 cells, and the production was inhibited by an inhibitor of I κB kinase-ß in a concentration-dependent manner. Furthermore, histone deacetylase 2 (HDAC2) knockdown by RNA interference, a mimic of oxidative-stress-dependent HDAC2 reduction, enhanced tumor necrosis factor-α-induced PAI-1 induction (half maximal effective concentration [EC50], 0.64 ± 0.19 ng/mL in HDAC2-KD, 7.64 ± 3.70 ng/mL in control) concomitant with enhancement of NF-κB p65 acetylation and NF-κB DNA-binding activity. CONCLUSIONS: Oxidative stress, directly or indirectly via HDAC reduction, plays a role in PAI-1 expression in COPD via activation of NF- κ B.

A novel macrolide solithromycin exerts superior anti-inflammatory effect via NF-κB inhibition.

Macrolides are reported to reduce exacerbation of chronic inflammatory respiratory disease, such as chronic obstructive pulmonary disease (COPD), and also show anti-inflammatory effects in vitro and in vivo. However the anti-inflammatory efficacies of current macrolides are relatively weak. Here we found that a novel macrolide/fluoroketolide solithromycin (CEM-101) showed superior anti-inflammatory effects to macrolides in current clinical use. The effects of solithromycin (SOL) on lipopolysaccharide-induced TNFα (tumor necrosis factor α) and/or CXCL8 (C-X-C motif chemokine ligand 8; interleukin-8) release, phorbol 12-myristate 13-acetate-induced MMP9 (matrix metalloproteinase 9) activity and NF-κB (nuclear factor-κB) activity under conditions of oxidative stress have been evaluated and compared with the effects of erythromycin, clarithromycin, azithromycin, and telithromycin in macrophage-like PMA-differentiated U937 cells and peripheral blood mononuclear cells (PBMC) obtained from COPD patients. We also examined effect of SOL on cigarette smoke-induced airway inflammation in mice. SOL exerted superior inhibitory effects on TNFα/CXCL8 production and MMP9 activity in monocytic U937 cells. In addition, SOL suppressed TNFα release and MMP9 activity in PBMC from COPD patients at 10 µM, which is 10 times more potent than the other macrolides tested. Activated NF-κB by oxidative stress was completely reversed by SOL. SOL also inhibited cigarette smoke-induced neutrophilia and pro-MMP9 production in vivo, although erythromycin did not inhibit them. Thus, SOL showed better anti-inflammatory profiles compared with macrolides currently used in the clinic and may be a promising anti-inflammatory and antimicrobial macrolide for the treatment of COPD in future.

Nasal manifestations of immunoglobulin G4-related disease.

OBJECTIVES/HYPOTHESIS: Immunoglobulin (Ig)G4-related disease is a systemic syndrome, characterized by sclerosing lesions that mainly affect the exocrine tissue. Although some patients with IgG4-related disease complain of nasal symptoms, there are few reports concerning the nasal manifestations of this disease. We investigated the clinical and pathological features of the nasal manifestations of IgG4-related disease. STUDY DESIGN: Retrospective review in a tertiary referral hospital. METHODS: Twenty-three consecutive patients with IgG4-related disease, six allergic rhinitis (AR) patients, and eight healthy subjects (HS) were evaluated. Nasal symptoms, local findings of the nasal cavity, and laboratory data were examined. Mucosal tissues from the inferior turbinate were obtained from all subjects before treatment. The level of IgG4-positive plasma cells and other infiltrating cells, and the number of nasal glands in the nasal subjects were compared among the three groups. RESULTS: Ten (43.4%) of 23 cases had some nasal symptoms, such as nasal obstruction and nasal crusting. Thirteen cases (56.5%) had numerous IgG4-positive plasma cell infiltration in the nasal mucosa. IgG4-positive plasma cells, CD3, and CD4 were significantly higher in the IgG4-related disease group than in the HS and AR groups, whereas the number of nasal glands in the IgG4-related disease group was significantly lower than in the HS and AR groups. CONCLUSIONS: The inflammatory lesions associated with IgG4-related disease exist on the nasal membrane. Thus, the nasal manifestations of IgG4-related disease were thought to be different from AR.

Giant frontal mucocele occurring 32 years after frontal bone fracture: a case report.

Giant mucoceles of the frontal sinus are rare but their recognition is important in the differential diagnosis of proptosis and fronto-orbital lesions. The authors describe a patient with frontal giant mucocele with intracranial as well as orbit and ethmoid sinus involvement. Thirty-two years after a frontal sinus fracture, a 51-year-old female presented with headache, and left exophthalmos and ophthalmoplegia. Computed tomography and magnetic resonance imaging demonstrated a giant frontal sinus mucocele with extension into the left anterior cranial fossa. The mucocele was treated with a transcranial and endoscopic transnasal approach. The frontal sinus was then cranialized with reconstruction of the posterior wall, and finally a wide nasal drainage was performed. The clinical symptoms disappeared immediately after surgery.

Otolaryngologic manifestations of antineutrophil cytoplasmic antibody-associated vasculitis.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis is characterized by systemic necrotizing vasculitis, and patients fall into 2 groups: those with proteinase 3-ANCA and those with myeloperoxidase-ANCA. As infections are a trigger of ANCA-associated vasculitis, this disease tends to localize in areas around the upper airway. In this study, the authors compared ear and nasal symptoms between patients with proteinase 3-ANCA and those with myeloperoxidase-ANCA. We undertook a retrospective case series study of 34 patients diagnosed with ANCA-associated vasculitis. The otologic symptoms were divided into 3 types: chronic otitis media, secretory otitis media, and sensorineural hearing loss. Chronic otitis media was more common in patients with proteinase 3-ANCA (P = .001), whereas secretory otitis media was more frequently found in patients with myeloperoxidase-ANCA (P = .007). Crust formation (P = .001), saddle nose (P = .024), and sinusitis (P = .001) were more common in patients with proteinase 3-ANCA than in those with myeloperoxidase-ANCA. Marked differences were observed in the disease spectrum between the 2 ANCA groups.

Dysregulation of histone deacetylase and histone acetyltransferase in development of Wegener's granulomatosis.

OBJECTIVES: We investigated the function of the decreases in histone deacetylase (HDAC) and histone acetyltransferase (HAT) in Wegener's granulomatosis (WG) patients compared with healthy subjects. METHODS: Seven patients with WG, diagnosed according to the American College of Rheumatology criteria, were examined. Fresh peripheral blood mononuclear cells were isolated from the WG patients and healthy subjects, and then whole-cell proteins were prepared. We measured the total HDAC and HAT activity in peripheral blood mononuclear cells from WG patients. The HDAC2 expression was analyzed by Western blot. RESULTS: We found that total HDAC activity was significantly decreased in WG patients compared to that in healthy subjects (p < 0.05). Furthermore, we found a negative correlation between total HDAC activity and C-reactive protein titer. Total HAT activity was significantly increased in WG patients. CONCLUSIONS: These results demonstrated reduced HDAC activity and an increase in HAT activity in WG. These were associated with concomitant induction of WG-related inflammation. Thus, dysregulation of HDAC and HAT may contribute to the disease pathogenesis of WG.

Preservation of the nasolacrimal duct during endoscopic medial maxillectomy for sinonasal inverted papilloma.

BACKGROUND: To assess the efficacy of a new endonasal medial maxillectomy technique (EMM) for the treatment of inverted papilloma (IP). METHODOLOGIES: A prospective series of 55 consecutive patients diagnosed with IP between March 2002 and April 2009 were entered into this study. The new surgical technique was applied to tumors arising from the anterior part of the maxillary sinus. After conventional EMM, the entire nasolacrimal duct was separated from the bony component of the nasolacrimal canal and preserved. Schirmer`s test and a visual analog scale (VAS) score were used to assess the lacrimal duct function after surgery. RESULTS: Ten of the 55 patients underwent the new surgical procedure. All patients were categorized with stage T3 or T4 tumors. No patients suffered tumor recurrence. There was no difference in lacrimal duct function between the diseased side and healthy side of the nasolacrimal duct. The mean VAS score was 2.8/100. CONCLUSIONS: This new surgical technique preserves the whole length of the nasolacrimal unit. It also offers several advantages including good visualization, nasolacrimal function after surgery and fewer adverse effects such as facial numbness and epiphora.

IL-21 enhances dendritic cell ability to induce interferon-gamma production by natural killer T cells.

Interleukin (IL)-21 shows pleiotropic effects on the proliferation, differentiation, and effector functions of leukocytes. However, the influence of IL-21 on dendritic cell (DC) activation of natural killer T (NKT) cells has not yet been elucidated. In the present study, we examined the effect of IL-21 on murine myeloid DC ability to induce NKT cell production of interferon-gamma (IFN-gamma) and IL-4. Pretreatment of DCs with IL-21 and alpha-galactosylceramide (alpha-GalCer), an NKT cell-specific ligand, resulted in the enhanced ability of the DCs to induce NKT cell production of IFN-gamma but not IL-4 in vitro compared to DCs pretreated with alpha-GalCer alone. A similar effect of IL-21 was observed when DCs pretreated with IL-21 and alpha-GalCer in vitro were transferred into naïve mice. Direct administration of IL-21 to the mice also enhanced IFN-gamma production after injection of alpha-GalCer. Thus, IL-21 can modify DC ability to selectively enhance NKT cell production of IFN-gamma upon stimulation with alpha-GalCer.

Natural killer T cells ameliorate antibody-induced arthritis in macrophage migration inhibitory factor transgenic mice.

Macrophage migration inhibitory factor (MIF) plays an important role in inflammatory diseases. It has been reported that anti-MIF treatment and mif-gene disruption ameliorate joint inflammation in a mouse model of arthritis induced by anti-type II collagen monoclonal antibodies and lipopolysaccharide (anti-IIC mAb/LPS). In the present study, using the anti-IIC mAb/LPS system, we have analyzed arthritis in MIF-transgenic (MIFTg) and wild-type C57BL/6 (WT) mice. We found that MIFTg mice developed more severe arthritis than WT mice. The histopathological scores were significantly higher in MIFTg mice and significantly increased numbers of CD69+ T cells were detected in the spleens of these arthritic MIFTg mice, compared with WT mice. Natural killer T (NKT) cells from MIFTg mice, compared with WT mice, produced reduced amounts of IL-4 upon stimulation with agr;-galactosylceramide (alpha-GalCer). Further, repeated administration of alpha-GalCer to MIFTg mice resulted in a profound reduction of both clinical and histopathological scores of arthritis, with a significant decrease in IL-6. The present findings demonstrate that overexpression of MIF exacerbates inflammation in this arthritis model and that NKT cells play an ameliorating role upon stimulation with alpha-GalCer in the inflammatory process in MIFTg mice.

[Prospective study of pollen dispersal prediction and identifying the usefulness of different parameters].

BACKGROUND: Birch pollen is the major pollen allergen in Hokkaido, Northern Japan. We reported a Betula masting model based on the resource budget model hypothesis. In addition to weather conditions, cumulative hours of sunlight and mean temperature from May to July of the previous year, this model used the amount of annual pollen dispersed in previous and penultimate years as a parameter based on data from 1990 to 2000. OBJECTIVE: We compared the predicted and observed amount of pollen dispersed for 3 years from 2001 to 2003 and evaluated the usefulness of each parameter in this model. METHODS: Birch pollen was measured using the Durham sampler at the Hokkaido University Graduate School of Medicine Research Institute in Sapporo. RESULTS: The difference between predicted and observed amounts of pollen dispersal was about 200-500 grains cm(-2). The annual pollen dispersed in the previous year was found to be the most useful parameter. CONCLUSION: This model is useful in predicting whether the amount of birch pollen will be less than average, about average, more than average, or much more than average.