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.

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.

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.

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.

Low positive titer of anti-melanoma differentiation-associated gene 5 antibody is not associated with a poor long-term outcome of interstitial lung disease in patients with dermatomyositis.

BACKGROUND: Anti-melanoma differentiation-associated gene 5 antibody (anti-MDA5-Ab) is associated with fatal rapidly progressive interstitial lung disease (RP-ILD) in patients with dermatomyositis (DM). We attempted to clarify whether anti-MDA5-Ab is associated with long-term outcomes in patients with DM-ILD. METHODS: Thirty-six patients with DM-ILD were retrospectively analyzed for their serum anti-MDA5-Ab by using an enzyme-linked immunosorbent assay. We analyzed the association between clinical parameters, including the serum levels of anti-MDA5-Ab and ferritin. RESULTS: Fourteen patients (39%) were positive for anti-MDA5-Ab. The serum levels of anti-MDA5-Ab and ferritin in 7 patients with acute death were higher than those in the surviving patients. An "unclassifiable pattern" on chest computed tomography and the development of RP-ILD were also prognostic markers. The serum levels of anti-MDA5-Ab and ferritin (cut-off levels, 100 IU/mL and 899 ng/mL, respectively) were markers predictive of acute death, showing good sensitivity (86% and 83%) and specificity (97% and 100%). All 7 patients with acute death developed RP-ILD and were positive for anti-MDA5-Ab, including 6 patients with a high titer (≥100 IU/mL), whereas only 2 patients (29%) developed RP-ILD among the 7 survivors with a low titer of anti-MDA5-Ab ( < 100 IU/mL). In contrast, a low positive titer of anti-MDA5-Ab was not associated with changes in pulmonary function for 2 years. CONCLUSIONS: Although a high serum titer of anti-MDA5-Ab (≥100 IU/mL) is associated with acute death via the development of RP-ILD, outcomes in the chronic phase for patients with a low titer of anti-MDA5-Ab ( < 100 IU/mL) were similar to those of patients without anti-MDA5-Ab.

The co-existence of Lemierre's syndrome and Bezold's abscesses due to Streptococcus constellatus: A case report.

RATIONALE: The ancient infectious diseases, Lemierre's Syndrome and Bezold's Abscesses are rare. PATIENT CONCERNS: A 70-year-old Japanese woman with a 15-year history of Parkinson's disease was referred to our hospital due to fever, occipital headache and bilateral shoulder pain that had continued for three months. She had been prescribed prednisolone due to a diagnosis of polymyalgia rheumatica. DIAGNOSES: A blood culture revealed bacteremia of Streptococcus constellatus. In addition, computed tomography revealed Bezold's abscesses and Lemierre's syndrome. INTERVENTIONS: We administered ceftriaxone for 31 days, followed by oral amoxicillin. OUTCOMES: The patient recovered and the abscesses improved. LESSONS: This case underscores the importance of blood culture tests and cross-referencing with radiological imagings in the diagnoses of these rare critical infectious diseases that mimic polymyalgia rheumatica.

Successful Treatment of Rapidly Progressive Unclassifiable Idiopathic Interstitial Pneumonia with Anti-melanoma Differentiation-associated Gene-5 Antibody by Intensive Immunosuppressive Therapy.

We describe a case of a woman who presented with a persistent cough, general fatigue, and a fever. Interstitial lung disease was rapidly progressive and resistant to high-dose steroid therapy. She tested positive for the presence of anti-melanoma differentiation-associated gene 5 (MDA-5) antibody, although she had no skin manifestations of dermatomyositis. She was eventually diagnosed with unclassifiable idiopathic interstitial pneumonia and was successfully treated with intensive immunosuppressive therapy including intravenous cyclophosphamide. To our knowledge, this is the first report of anti-MDA-5 antibody in a patient with idiopathic interstitial pneumonia.