Soluble form of the MDA5 protein in human sera.

Viral double-stranded RNA (dsRNA) is sensed by toll-like receptor 3 (TLR3) and retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs), including melanoma differentiation-associated gene 5 (MDA5). MDA5 recognizes the genome of dsRNA viruses and replication intermediates of single-stranded RNA viruses. MDA5 also plays an important role in the development of autoimmune diseases, such as Aicardi-Goutieres syndrome and type I diabetes. Patients with dermatomyositis with serum MDA5 autoantibodies (anti-CADM-140) are known to have a high risk of developing rapidly progressive interstitial lung disease and poor prognosis. However, there have been no reports on the soluble form of MDA5 in human serum. In the present study, we generated in-house monoclonal antibodies (mAbs) against human MDA5. We then performed immunohistochemical analysis and sensitive sandwich immunoassays to detect the MDA5 protein using two different mAbs (clones H27 and H46). As per the immunohistochemical analysis, the MDA5 protein was moderately expressed in the alveolar epithelia of normal lungs and was strongly expressed in the cytoplasm of lymphoid cells in the tonsils and acinar cells of the pancreas. Interestingly, soluble MDA5 protein was detectable in the serum, but not in the urine, of healthy donors. Soluble MDA5 protein was also detectable in the serum of patients with dermatomyositis. Immunoblot analysis showed that human cells expressed a 120 kDa MDA5 protein, while the 60 kDa MDA5 protein increased in the supernatant of peripheral mononuclear cells within 15 min after MDA5 agonist/double-strand RNA stimulation. Hydrogen deuterium exchange mass spectrometry revealed that an anti-MDA5 mAb (clone H46) bound to the epitope (415QILENSLLNL424) derived from the helicase domain of MDA5. These results indicate that a soluble MDA5 protein containing the helicase domain of MDA5 could be rapidly released from the cytoplasm of tissues after RNA stimulation.

Examination of Prognostic Factors in Anti-Melanoma Differentiation-Associated Gene 5 Antibody-Positive Dermatomyositis.

OBJECTIVE: This study investigated the prognostic factors of anti-melanoma differentiation-associated gene 5 antibody-positive dermatomyositis (MDA5-DM). METHODS: This study analysed 34 MDA5-DM cases (20 and 14 in the survival and death groups, respectively) encountered at Kurume University between 2008 and 2021. The clinical, physiological, and computed tomography findings, pulmonary function, and serological results were retrospectively evaluated for each MDA5-DM case during the first visit and throughout the next 12 weeks. RESULTS: In the death group, the mean age of patients was higher (47.6 vs. 61.8 years), while the duration from symptom onset to consultation was shorter (110 vs. 34.9 days). During the first visit, the death group demonstrated a significantly higher serum C-reactive protein (CRP) level (0.52 vs. 1.99) and a significantly lower albumin level (3.23 vs. 2.63) than the survival group; this persisted throughout the next 12 weeks. Poor prognosis was associated with CRP and albumin levels above 0.19 mg/dL and below 2.3 g/dL, respectively, 4 weeks after starting treatment. CONCLUSION: Four weeks after beginning treatment, serum CRP and albumin levels of patients with MDA5-DM can be used to evaluate treatment response and predict prognosis.

IL-18 receptor-α signalling pathway contributes to autoantibody-induced arthritis via neutrophil recruitment and mast cell activation.

OBJECTIVES: The interleukin (IL)-18 signalling pathway is involved in animal models of collagen-induced arthritis, but the role of this pathway in autoantibody-induced arthritis is poorly understood. An autoantibody-induced arthritis model, K/BxN serum transfer arthritis, reflects the effector phase of arthritis and is important in innate immunity including neutrophils and mast cells. This study aimed to investigate the role of the IL-18 signalling pathway in autoantibody-induced arthritis using IL-18 receptor (IL-18R) α-deficient mice. METHODS: K/BxN serum transfer arthritis was induced in IL-18Rα-/- and wild-type B6 (controls) mice. The severity of arthritis was graded, and histological and immunohistochemical examinations were performed on paraffin-embedded ankle sections. Total Ribonucleic acid (RNA) isolated from mouse ankle joints was analysed by real-time reverse transcriptase-polymerase chain reaction. RESULTS: IL-18 Rα-/- mice had significantly lower arthritis clinical scores, neutrophil infiltration, and numbers of activated, degranulated mast cells in the arthritic synovium than in controls. IL-1ß, which is indispensable for the progression of arthritis, was significantly downregulated in inflamed ankle tissue in IL-18 Rα-/- mice. CONCLUSIONS: IL-18/IL-18Rα signalling contributes to the development of autoantibody-induced arthritis by enhancing synovial tissue expression of IL-1ß and inducing neutrophil recruitment and mast cell activation. Therefore, inhibition of the IL-18Rα signalling pathway might be a new therapeutic strategy for rheumatoid arthritis.

Periostin Is a Biomarker of Rheumatoid Arthritis-Associated Interstitial Lung Disease.

Periostin was investigated as a biomarker for rheumatoid arthritis-associated interstitial lung disease (RA-ILD). This prospective study measured serum monomeric and total periostin, Klebs von den Lungen-6 (KL-6), surfactant protein D (SP-D), and lactate dehydrogenase (LDH) in 19 patients with RA-ILD, 20 RA without ILD, and 137 healthy controls (HC). All biomarkers were higher in RA-ILD than HC or RA without ILD. KL-6 accurately detected ILD in RA patients (area under curve [AUC] = 0.939) and moderately detected SP-D and monomeric and total periostin (AUC = 0.803, =0.767, =0.767, respectively). Monomeric and total periostin were negatively correlated with normal lung area and positively correlated with honeycombing, reticulation, fibrosis score, and the traction bronchiectasis grade but not inflammatory areas. Serum levels of SP-D, KL-6, and LDH did not correlate with the extent of those fibrotic areas on high-resolution CT. Serum monomeric and total periostin were higher in patients with RA-ILD with definite usual interstitial pneumonia pattern compared with other ILD patterns. Immunohistochemical analyses of biopsy or autopsy lung tissues from RA-ILD during the chronic phase and acute exacerbation showed that periostin was expressed in fibroblastic foci but not inflammatory or dense fibrosis lesions. Periostin is a potential biomarker for diagnosis, evaluating fibrosis, and deciding therapeutic strategies for patients with RA-ILD.

Combination of Prednisolone and Calcineurin Inhibitors Prevents Lung Function Decline in Patients with Anti-aminoacyl-tRNA Synthetase Antibody-Positive Polymyositis/Dermatomyositis.

OBJECTIVE: Anti-aminoacyl-tRNA synthetase antibody-positive polymyositis/dermatomyositis-associ ated interstitial lung disease (ARS-ILD) has a good prognosis, with few cases progressing to respiratory failure. This study aimed to determine factors predictive of lung function changes in patients with ARS-ILD. METHODS: We retrospectively studied 49 patients with ARS-ILD treated at Kurume University Hospital Hospital between 2000 and 2018. We followed 30 patients for more than 2 years after prednisolone (PSL) therapy, with or without calcineurin inhibitors (CNIs), evaluating clinical, physiological, computed tomography, pulmonary func tion, and serological data. RESULTS: After treatment for 24 months, no significant differences were noted between clinical parameters and improvement in forced vital capacity (FVC), %FVC, % carbon monoxide diffusing capacity/alveolar volume (%DLCO), and %DLCO/alveolar volume. Conversely, the annual change of %FVC significantly correlated with the Medical Research Council dyspnea scale grade and %FVC at the first visit and treatment. Furthermore, the annual change of %DLCO/VA significantly correlated with the duration from the first visit to treatment initiation. CONCLUSION: Compared with PSL monotherapy, combining PSL and CNI showed greater mitigation of %FVC decline. The time from onset of ARS-ILD to the first visit is critical for preventing a decline in lung function, and as such, patients should be monitored carefully.

Positive Autoantibody Is Associated with Malignancies in Patients with Idiopathic Interstitial Pneumonias.

Various autoantibodies are associated with clinical outcomes in patients with idiopathic interstitial pneumonias (IIPs). We retrospectively analyzed the association between autoantibodies and malignancies in IIP patients. Comprehensive analyses of autoantibodies were performed using immunoprecipitation and enzyme-linked immunosorbent assays in 193 consecutive IIP patients. Cancer-related factors were analyzed using logistic regression analysis. In total, 22 of 193 patients (11.4%) with IIP had malignant disease. In univariate analysis, positivity for any autoantibody (odds ratio (OR), 3.1; 95% confidence interval (CI), 1.2-7.7; p = 0.017) and antinuclear antibody titer ≥1:320 (OR, 3.4; CI, 1.2-9.8; p = 0.024) were significantly associated with malignancies. Positive anti-aminoacyl tRNA synthetase (ARS) (OR, 3.7; CI, 0.88-15.5; p = 0.074) and anti-Ro52 antibody (OR, 3.2; CI, 0.93-11.2; p = 0.065) tended to be associated with malignancies. In multivariate analysis, independent risk factors were male sex (OR, 3.7; CI, 1.0-13.5; p = 0.029) and positivity for any autoantibody (OR, 3.9; CI, 1.5-10.1; p = 0.004) in model 1, and male sex (OR, 3.9; CI, 1.0-15.3; p = 0.049), antinuclear antibody titer ≥1:320 (OR, 4.2; CI, 1.4-13.3; p = 0.013), and positivity for anti-ARS antibody (OR, 6.5; CI, 1.2-34.1; p = 0.026) in model 2. Positivity for any autoantibody, antinuclear and anti-ARS antibodies, and male sex were independent risk factors for malignancies in IIP patients. Testing autoantibodies in IIP patients might help the early diagnosis of malignancies.

Clinical Characteristics of Anti-TIF-1γ Antibody-Positive Dermatomyositis Associated with Malignancy.

We retrospectively analyzed the clinical and laboratory data of patients diagnosed with anti-transcriptional intermediary factor 1 (TIF-1γ) antibody-positive polymyositis (PM)/dermatomyositis (DM) to clarify the characteristics of this disease. We identified 14 patients with TIF-1γ antibody-positive DM (TIF-1γ DM), 47 with anti-aminoacyl-tRNA synthetase antibody (ARS)-positive PM/DM, and 24 with anti-melanoma differentiation-associated gene 5 antibody (MDA-5)-positive PM/DM treated at the Kurume University Hospital between 2002 and 2020. Patients with TIF-1γ DM were significantly older than the other two groups. Nine patients with TIF-1γ DM were female, thirteen patients had DM, and one had clinically amyopathic DM. Primary malignant lesions were lung (3), uterus (2), colon (2), breast (2), ovary (1), lymphoma (1), and unknown (2). Cutaneous manifestation and dysphagia were the most common symptoms in TIF-1γ DM. Erythema (9/14), the V-neck sign (8/14), heliotrope (9/14), and nailfold telangiectasia (14/14) were significantly more common in TIF-1γ DM. Furthermore, no patients with TIF-1γ DM had interstitial lung abnormality on high-resolution CT. In patients with TIF-1γ DM, the frequency of dysphagia and unusual erythema, particularly that which spreads from the trunk, and nailfold telangiectasia, were characteristic findings. In most patients with TIF-1γ DM, it is necessary to administer other immunosuppressive drugs along with glucocorticoids.

Mast cells can produce transforming growth factor ß1 and promote tissue fibrosis during the development of Sjögren's syndrome-related sialadenitis.

OBJECTIVES: This study investigated the associations of mast cells with immune-mediated inflammation and fibrosis in patients with primary Sjögren's syndrome (pSS); it also explored the underlying pathophysiology of pSS-related sialadenitis. METHODS: Twenty-two patients with pSS and 10 patients with sicca (control individuals) underwent labial salivary gland biopsies. Sections were subjected to staining and immunofluorescence analyses. HMC-1 human mast cells were cocultured with fibroblasts in vitro; fibroblasts were also grown in HMC-1 conditioned medium. mRNA levels of collagen Type I (Col1a) and transforming growth factor (TGF)ß1 were analysed in cultured cells. RESULTS: Mast cell numbers in labial salivary glands were significantly greater in patients with pSS than in control individuals. In salivary glands from patients with pSS, mast cell number was significantly correlated with fibrosis extent; moreover, mast cells were located near fibrous tissue and expressed TGFß1. Col1a and TGFß1 mRNAs were upregulated in cocultured fibroblasts and HMC-1 cells, respectively. Fibroblasts cultured in HMC-1 conditioned medium exhibited upregulation of Col1a mRNA; this was abrogated by TGFß1 neutralizing antibodies. CONCLUSIONS: Mast cell numbers were elevated in patients with pSS-related sialadenitis; these cells were located near fibroblasts and expressed TGFß1. TGFß1 could induce collagen synthesis in fibroblasts, which might contribute to fibrosis.

Subcutaneous Cheek Nodule Associated with Granulomatosis with Polyangiitis.

We herein report an unusual case of granulomatosis with polyangiitis (GPA) in a 65-year-old man in whom relapsed disease manifested as an anterior cheek nodule. Magnetic resonance imaging indicated the differential diagnoses of the subcutaneous nodule in the patient's anterior cheek to be inflammatory granulomatous lesions with GPA, malignancy, or infectious disease. A histopathological examination ruled out malignancy and infectious diseases, and necrotizing vasculitis was suspected. The subcutaneous nodule was successfully treated using rituximab, suggesting that it was associated with GPA, secondary to vasculitis. Clinicians should be aware of the possibility of such a rare manifestation of GPA.

MEFV E148Q variant is more associated with familial Mediterranean fever when combined with other non-exon 10 MEFV variants in Japanese patients with recurrent fever.

OBJECTIVE: To investigate the genetic characteristics of one of the MEFV gene variants, p.Glu148Gln (E148Q), in patients with familial Mediterranean fever (FMF) and examine its significance in Japanese patients with recurrent fever. METHODS: The clinical phenotype and genomic variants of systemic autoinflammatory diseases (SAIDs), including MEFV, were analyzed in 211 Japanese patients with recurrent fever. Genetic analysis was performed via next-generation sequencing of exons, including exon-intron boundaries. RESULTS: Twelve patients met the diagnostic criteria for SAIDs other than FMF. Considering 199 patients with recurrent fever, 137 cases (68.8%) were clinically diagnosed with FMF. Although Bonferroni-adjusted p-value did not reach significance level, the group containing heterozygous E148Q and other variants tended to be at higher risk of developing the FMF phenotype (nominal p = .036) than the group with heterozygous E148Q only. Comparison between the group with heterozygous E148Q and other variants and the heterozygous group containing non-E148Q showed no statistically significant difference in FMF phenotype expression (nominal p = 1.00). CONCLUSION: Patients with heterozygous E148Q and other variants exhibited higher expression of FMF phenotype than those with heterozygous E148Q only, and suggested that other variants than E148Q as well as exon 10 variants might contribute to the FMF phenotype.

Clinical phenotypes and genetic analyses for diagnosis of systemic autoinflammatory diseases in adult patients with unexplained fever.

OBJECTIVE: To make an accurate diagnosis of systemic autoinflammatory diseases (SAIDs), clinical and genetic analyses were performed in patients with unexplained fever. METHODS: The clinical phenotype and genomic variants of 11 genes responsible for SAIDs were analyzed in 179 Japanese patients with unexplained fever. Genetic analysis was performed by next generation sequencing (NGS) on exons including exon-intron boundaries. RESULTS: Three cases met the diagnostic criteria for SAIDs other than familial Mediterranean fever (FMF). Considering 176 patients with unexplained fever, 43 cases (24.0%) were clinically diagnosed as FMF. Gene variants were found in 53 cases (30.1%) when searching for variants in the 10 disease genes other than the MEFV gene. Among them, the most frequently-identified genes were NLRP3, NOD2, NLRP12, NLRC4, and PLCG2, which accounted for 14, 7, 17, 7, and 6 cases, respectively. These variants were less than 1% of healthy individuals or novel variants, but not regarded as pathogenic since the patients did not meet the diagnostic criteria of SAIDs caused by their identified variants clinically. CONCLUSION: Twenty four percent of Japanese patients with unexplained fever were clinically diagnosed as FMF in this study. Low frequency but not pathogenic variants in genes other than MEFV were identified in 30.1% of the cases. It is not clear how much these gene variants contribute to the inflammatory phenotypes; therefore, further analysis would uncover their autoinflammatory phenotypes that cause fever.

Risk Prediction Modeling Based on a Combination of Initial Serum Biomarker Levels in Polymyositis/Dermatomyositis-Associated Interstitial Lung Disease.

OBJECTIVE: To establish predictive models for mortality in patients with polymyositis/dermatomyositis-associated interstitial lung disease (PM/DM-ILD) using a combination of initial serum biomarker levels. METHODS: The Multicenter Retrospective Cohort of Japanese Patients with Myositis-Associated ILD (JAMI) database of 497 incident cases of PM/DM-ILD was used as a derivation cohort, and 111 cases were additionally collected as a validation cohort. Risk factors predictive of all-cause mortality were identified by univariate and multivariable Cox regression analyses using candidate serum biomarkers as explanatory variables. The predictive models for mortality were generated in patients with and those without anti-melanoma differentiation-associated gene 5 (MDA-5) antibody, using a combination of risk factors. Cumulative survival rates were assessed using Kaplan-Meier analysis, and were compared between subgroups using the Breslow test. RESULTS: In the derivation cohort, C-reactive protein (CRP) and Krebs von den Lungen 6 (KL-6) levels were identified as independent risk factors for mortality in both anti-MDA-5-positive and anti-MDA-5-negative patients. We then developed a prediction model based on anti-MDA-5 antibody status, CRP level, and KL-6 level, termed the "MCK model," to identify patients at low (<15%), moderate (15-50%), or high (≥50%) risk of mortality, based on the number of risk factors. The MCK model successfully differentiated cumulative survival rates in anti-MDA-5-positive patients (P < 0.01 for low versus moderate risk and P = 0.03 for moderate versus high risk) and in anti-MDA-5-negative patients (P < 0.001 for low versus moderate risk). The utility of the MCK model was replicated in the validation cohort. CONCLUSION: Our findings indicate that an evidence-based risk prediction model using CRP and KL-6 levels combined with anti-MDA-5 antibody status might be useful for predicting prognosis in patients with PM/DM-ILD.

CD163 deficiency facilitates lipopolysaccharide-induced inflammatory responses and endotoxin shock in mice.

OBJECTIVES: Septic (or endotoxin) shock is a severe systemic inflammatory disease caused by bacteraemia or endotoxaemia. Although it is known that increased serum levels of CD163 are observed in septic/endotoxin shock patients, the exact function and significance of CD163 in macrophage activation remain unclear. Therefore, in the current study, we tested whether CD163 contributes to the pathogenesis of endotoxin shock in mice. METHODS AND RESULTS: In samples obtained from autopsy, the number of CD163-positive macrophages was increased in the kidney, liver, heart, bone marrow and spleen of patients who had died from septic/endotoxin shock when compared to patients who had died from other causes. The animal study revealed a significantly lower survival rate in CD163-deficient mice after lipopolysaccharide (LPS) injection. Several cytokines and oxidative stress-related molecules were significantly elevated in the sera of LPS-induced endotoxin shock mice models. Higher concentrations of IL-6, TNF-α, IL-1ß, nitrite ( NO 2 - ) and nitrate ( NO 3 - ) and a lower concentration of IL-10 were observed in CD163-deficient mice treated with LPS. Similar results were observed in CD163-deficient LPS-stimulated macrophages. Furthermore, in an antitype II collagen antibody-induced arthritis (CAIA), rheumatoid arthritis model, inflammation and bone erosion scores as well as the expression of IL-6 and IL-1ß were significantly increased in CD163-deficient mice. CONCLUSIONS: CD163 was suggested to be involved in the regulation of inflammatory cytokine expression in septic/endotoxin shock and CAIA.

Evaluation of usefulness in surfactant protein D as a predictor of mortality in myositis-associated interstitial lung disease.

OBJECTIVE: Surfactant protein D (SP-D) is considered a serum biomarker of various forms of interstitial lung disease (ILD). In this study, we examined the utility of SP-D as a predictive biomarker for mortality in patients with ILD associated with polymyositis/dermatomyositis (PM/DM) using large-scale multicentre cohort data. METHODS: We enrolled 381 patients with incident PM/DM-associated ILD in a multicentre retrospective cohort based on the availability of serum SP-D at the baseline. Demographic and clinical characteristics as well as the presence of autoantibodies to melanoma differentiation-associated gene 5 (MDA5) and aminoacyl tRNA synthetase were measured at the time of diagnosis, and follow-up survival data were collected prospectively. RESULTS: Seventy-eight patients died during the median observation period of 18 months, and the majority of patients died of ILD. The SP-D levels at baseline were significantly lower (P = 0.02) in a non-survivor subset than in a survivor subset among the entire enrolled patients. However, the SP-D levels were higher in the non-survivor subset than in the survivor subset based on the stratification by anti-MDA5-positive, anti-ARS-positive and, double-negativity, although there was an only statistically significant difference (P = 0.01) in the double-negative group. Surprisingly, the SP-D levels were within the upper limit of normal, 110 ng/mL, in 54 (87%) of 62 anti-MDA5-positive patients who died. In the double-negative group, the mortality rates were significantly higher (P = 0.002) in a subset with SP-D ≥127.6 ng/mL, the cut-off value for mortality calculated by the receiver operating characteristic curve, than the other subset. All of patients with SP-D <127.6 ng/mL survived. CONCLUSION: Serum SP-D levels behave differently among patients with stratified by anti-MDA5 antibody, anti-ARS antibody and both negativity in PM/DM-associated ILD. Its use in clinical practice should be applied with caution on the basis of the presence or absence of anti-MDA5 antibody or anti-ARS antibody.

Clinical and Genetic Analysis of 22 Japanese Patients with Familial Mediterranean Fever: An Examination of MEFV and 10 Other Genes Related to Autoinflammatory Syndromes.

Objective Familial Mediterranean Fever (FMF) is the most frequent autoinflammatory syndrome, and its frequency is reported to be increasing in Japan. We studied the clinical features and genetic background of patients with FMF in our hospital. Methods We analyzed the clinical features and genomic variants of MEFV, as well as 10 genes related to other autoinflammatory syndromes, in 22 Japanese patients with FMF. A genetic analysis was performed with a next generation sequencer. Results The patients were classified into the typical FMF (n=16) and atypical FMF (n=6) groups. Fever, abdominal pain, thoracic pain, and arthralgia were observed in 22, 12, 8, and 10 patients, respectively. MEFV variants were found in 19 patients (86.4%). Two cases had no MEFV variants and one case only had a variant in the 3' untranslated region (3'-UTR) of MEFV. Genomic variants were found in genes other than MEFV in 7 patients (31.8%); however, none met the diagnostic criteria for autoinflammatory syndromes with disease-related gene variants, and all were classified as typical FMF. Moreover, none of the 6 patients with atypical FMF had any variants among the 10 disease-related genes. All cases in which the onset occurred before 20 years of age were classified as typical FMF. Conclusion The clinical features of FMF recorded in our hospital coincided with those from the Japanese national epidemiological survey of FMF in Japan. More than 30% of the patients with FMF had non-MEFV genes, related to other autoinflammatory syndromes, thereby suggesting that variants of these genes may act as a disease-modifier in FMF.

Elevation of pulmonary CD163+ and CD204+ macrophages is associated with the clinical course of idiopathic pulmonary fibrosis patients.

BACKGROUND: M2-like/repair macrophages are thought to contribute to fibrotic process of idiopathic pulmonary fibrosis (IPF). We analyzed the association between pulmonary accumulation of M2-like macrophages and survival in IPF patients. METHODS: Lung tissues were obtained by surgical lung biopsy from patients with IPF (n=16), nonspecific interstitial pneumonia (NSIP, n=8) and control subjects (n=14). Samples were also obtained at autopsy from 9 patients who died of acute exacerbation (AE) of IPF. Lung specimens and/or human peripheral blood mononuclear cells-derived macrophages were evaluated by immunohistochemistry for expression of CD68 (pan-macrophage marker), CD163, and CD204 (M2-like macrophage markers), and by in situ mRNA hybridization and ELISA for production of transforming growth factor-ß1 (TGF-ß1). RESULTS: CD68+, CD163+, and CD204+ cell counts and CD163+/CD68+ and CD204+/CD68+ cell ratios were comparable in IPF and NSIP lung tissues and significantly higher than in control tissues. IPF-AE lung samples contained significantly elevated CD68+ and CD163+ cell counts and CD163+/CD68+ cell ratio compared with IPF samples, whereas CD204+ cell counts and CD204+/CD68+ cells ratio did not differ. High CD163+/CD68+ and CD204+/CD68+ cell ratios were significantly associated with shorter overall survival and time-to-AE in IPF patients. In vitro-differentiated human CD163+ and CD204+ macrophages both secreted TGF-ß1; however, the novel IPF drug pentraxin 2/serum amyloid protein could suppress secretion only by CD204+ macrophages. CONCLUSIONS: Pulmonary accumulation of CD163+ and CD204+ macrophages is associated with worse clinical course in IPF patients. Suppression of macrophage activation and TGF-ß1 secretion may be a potential therapeutic target for IPF.

A retrospective study of the tolerability of nintedanib for severe idiopathic pulmonary fibrosis in the real world.

BACKGROUND: Nintedanib is a tyrosine kinase inhibitor that has been shown to suppress progression of idiopathic pulmonary fibrosis (IPF). The efficacy and tolerability of nintedanib for IPF has been previously proven in the INPULSIS® and INPULSIS-On® trials. The aim of our study was to clarify the tolerability of nintedanib in the real world for severe IPF patients who were unable to enter the INPULSIS® and INPULSIS-On® trials. METHODS: We retrospectively investigated medical records of 8 patients with severe IPF and 14 patients with non-severe IPF who had been treated with nintedanib. The criteria to define severe IPF were forced vital capacity (FVC) of <50% predicted and/or diffusing capacity of the lung for carbon monoxide/alveolar volume (DLCO/VA) of <30% predicted or unmeasurable. Severity of adverse event was evaluated using the Common terminology criteria for each adverse event version 4.0. We compared changes in FVC and serum KL-6 level, incidence and severity of adverse events, and incidence of permanent or temporary discontinuation of nintedanib in between severe and non-severe IPF groups. RESULTS: The median treatment period was 578.5 days. The most frequent adverse event was diarrhea (73%). Only 2 patients required permanent discontinuation of nintedanib due to adverse events. There was no difference in incidence or severity of adverse events or incidence of permanent or temporary discontinuation of nintedanib in between severe and non-severe IPF groups. Among subjects, decline in FVC during 6 months post-nintedanib treatment were significantly lower than prior to treatment, but change in serum KL-6 level showed no significant difference between these 2 timepoints. CONCLUSIONS: Our study showed that nintedanib was tolerable for IPF patients who would not have been eligible for entry into previous clinical trials due to low pulmonary function. Although therapeutic strategy for severe IPF should be planned carefully, initiation of nintedanib treatment should not be dismissed solely for reasons of low pulmonary function.