Clinical features of acute fibrinous and organizing pneumonia: An early histologic pattern of various acute inflammatory lung diseases.

BACKGROUND: Acute fibrinous and organizing pneumonia (AFOP) is a rare histologic pattern of acute lung involvement with intra-alveolar fibrin deposition. However, the clinical significance of the pathological findings of AFOP remains unclear. This study aimed to explore the clinical significance of AFOP through a comprehensive clinical examination. METHODS: The medical records of patients with lung diseases accompanied by the pathological finding of intra-alveolar organization between January 2010 and December 2019 were retrospectively reviewed. The clinical and radiological findings were compared between the groups with and without the histologic pattern of AFOP. RESULTS: We identified 34 patients with AFOP (AFOP group) and 143 without AFOP (non-AFOP group). The underlying diseases of the AFOP group were as follows: 19 patients had cryptogenic organizing pneumonia (OP), 5 had connective tissue diseases, 3 had radiation pneumonitis, 3 had chronic eosinophilic pneumonia, 2 had myelodysplastic syndromes, and 2 had drug-induced pneumonia. Fever was more common, the time from symptom onset to biopsy was shorter, and the serum C-reactive protein level was higher in the AFOP group than in the non-AFOP group. On high-resolution computed tomography, 85% of patients had OP pattern, and halo sign was more common in the AFOP group. Corticosteroids were effective in 94% of the patients in the AFOP group; however, recurrences were more frequent, and a higher corticosteroid dose was needed during recurrence. CONCLUSIONS: AFOP might be an early phase of a histologic pattern associated with known etiologies. In addition, it could be a marker indicating intense inflammatory diseases with a tendency of recurrence.

Clinical features of chronic summer-type hypersensitivity pneumonitis and proposition of diagnostic criteria.

BACKGROUND: Trichosporon asahii (T. asahii) causes chronic summer-type hypersensitivity pneumonitis (C-SHP); however, little is known about the clinical features of this condition. We aimed to elucidate the clinical features of C-SHP and propose practical diagnostic criteria for C-SHP based on the presence of serum anti-T. asahii antibody (TaAb). METHODS: Patients diagnosed with C-SHP and idiopathic pulmonary fibrosis (IPF) between January 2010 and May 2017 were reviewed retrospectively. Clinical findings were compared between the two groups. Criteria for C-SHP were proposed on the basis of significant characteristics and applied to the development and validation cohorts. RESULTS: Thirty-one patients with C-SHP and 26 with TaAb-negative IPF were identified. C-SHP patients were more likely to live in wooden houses; their serum Krebs von den Lungen-6 (KL-6) and serum surfactant protein-D (SP-D) levels were higher than those of IPF patients. C-SHP patients were more likely to have subpleural consolidation, micronodules, and extensive ground-glass opacification on high-resolution computed tomography (HRCT). The following 3 items were considered to have diagnostic value: I) TaAb positivity; II) an HRCT pattern consistent with chronic hypersensitivity pneumonitis, including mosaic attenuation or micronodules; and III) elevated serum biomarker levels (KL-6 > 1500 U/mL or SP-D > 250 ng/mL). We defined cases satisfying I) and II) as "probable C-SHP" and those satisfying all 3 criteria as "confident clinical diagnosis of C-SHP". The areas under the receiver-operating curve were 0.965 and 0.993 in the development and validation cohorts, respectively, which suggested that these criteria had good discriminative ability in clinical evaluations. CONCLUSIONS: Clinical features could be useful for distinguishing C-SHP from IPF and other etiologies of ILDs.

Factors associated with the relapse of cryptogenic and secondary organizing pneumonia.

BACKGROUND: Organizing pneumonia (OP) is a histopathological response pattern to lung inflammation. It is clinically classified into cryptogenic OP and secondary OP, which is associated with various clinical conditions. Rapid resolution with corticosteroids and frequent relapses are common in OP. However, few studies have investigated the factors associated with OP relapse. METHODS: The medical records of 75 patients with biopsy-proven OP, diagnosed between January 2010 and August 2015, who underwent corticosteroid therapy were retrospectively reviewed. Initially, the patients were all treated successfully; however, 31 patients experienced relapse thereafter (R group), whereas the others did not (NR group; 44 patients). The clinical, radiological, and pathological characteristics and administered corticosteroid doses were compared between the two groups. RESULTS: The neutrophil percentage in the bronchoalveolar lavage (BAL) fluid and the level of fibrin deposition in lung biopsy specimens were higher in the R group than in the NR group (P=0.01 and P=0.002, respectively). The multivariate analysis demonstrated that both factors were statistically significant predictors of OP relapse. CONCLUSIONS: A high neutrophil percentage in the BAL and the level of fibrin deposition in lung biopsy specimens are considered predictive factors of OP relapse during the tapering or after the cessation of steroid therapy. Patients without these findings may be treated with low-dose corticosteroids.

IgG4-related disease in asbestos-related pleural disease.

A 67-year-old man with a history of asbestos exposure and rounded atelectasis complained of cough and swelling in the left submandibular region. Computed tomography showed an increase in size of the right lower lung lobe lesion, which was recognized as the pre-existing rounded atelectasis, as well as swelling of the pancreas and submandibular glands. Biopsy from a submandibular gland and the pulmonary lesion led to a diagnosis of immunoglobulin G4-related disease (IgG4-RD). IgG4-RD is a recently recognized disease that was first reported as an autoimmune disease; however, some reports have indicated another pathogenesis of an allergic nature that is characterized by type 2 helper T cell (Th2) inflammation. Additionally, it is recognized that long-term exposure to asbestos can cause immune dysregulation. Here we present a case of IgG4-RD associated with asbestos-related pleural disease. Asbestos-induced immune dysregulation may be one etiology of IgG4-RD.

A case of diffuse panbronchiolitis, associated with severe pulmonary hypertension, managed with bilateral lung transplantation from a brain-dead donor.

Diffuse panbronchiolitis (DPB) is a chronic respiratory disease that mainly involves the respiratory bronchioles, and has historically been associated with a very poor prognosis. The development of long-term low dose macrolide therapy in the 1980s has dramatically improved the prognosis of DPB. Nevertheless, some cases are resistant to macrolide therapy, and ultimately develop severe respiratory failure and pulmonary hypertension; in such cases lung transplantation is a viable treatment option. Here we report the case of a 40-year-old patient with a 20-year history of DPB, who underwent bilateral lung transplantation due to severe respiratory failure with pulmonary hypertension.

IgG4-related lung disease with organizing pneumonia effectively treated with azathioprine.

Immunoglobulin (Ig)-G4-related disease is a multi-organ disease that may affect the lung. We herein describe a patient with IgG4-related lung disease (IgG4-RLD) who was radiologically and pathologically diagnosed with organizing pneumonia. He was successfully treated with a combination of prednisolone (PSL) and azathioprine (AZA), and his clinical course has been uneventful since tapering off PSL. This is a rare case of IgG4-RLD manifesting as organizing pneumonia, and, to our knowledge, this is also the first case showing the effectiveness of AZA in treating IgG4-RLD.