Efficient detection of somatic UBA1 variants and clinical scoring system predicting patients with variants in VEXAS syndrome.

OBJECTIVES: To efficiently detect somatic UBA1 variants and establish a clinical scoring system predicting patients with pathogenic variants in VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome. METHODS: Eighty-nine Japanese patients with clinically suspected VEXAS syndrome were recruited [81 males and 8 females; median onset age (IQR) 69.3 years (62.1-77.6)]. Peptide nucleic acid-clamping PCR (PNA-PCR), regular PCR targeting exon 3 clustering UBA1 variants, and subsequent Sanger sequencing were conducted for variant screening. Partitioning digital PCR (pdPCR) or targeted amplicon deep sequencing (TAS) was also performed to evaluate the variant allele frequency (VAF). We developed our clinical scoring system to predict UBA1 variant-positive and ­negative patients and assessed the diagnostic value of our system using receiver operating characteristic (ROC) curve analysis. RESULTS: Forty patients with reported pathogenic UBA1 variants (40/89, 44.9%) were identified, including a case having a variant with VAF of 1.7%, using a highly sensitive method. Our clinical scoring system considering >50 years of age, cutaneous lesions, lung involvement, chondritis, and macrocytic anaemia efficiently predicted patients with UBA1 variants (the area under the curve for the scoring total was 0.908). CONCLUSIONS: Genetic screening with the combination of regular PCR and PNA-PCR detected somatic UBA1 variants with high sensitivity and specificity. Our scoring system could efficiently predict patients with UBA1 variants.

Clinical features of dermatomyositis associated with anti-MDA5 antibodies by age.

OBJECTIVES: Anti-melanoma differentiation-associated gene 5 (MDA5) autoantibody-positive and age at onset ≥60 years are poor prognosis factors in polymyositis (PM) and dermatomyositis (DM) associated with interstitial lung disease (ILD) among Japanese patients. However, the influence of age on the clinical features of anti-MDA5 autoantibody-positive patients with DM remains unclear. METHODS: We retrospectively examined 40 patients with DM and anti-MDA5 autoantibodies according to age. We compared patients aged <60 and ≥60 years with respect to clinical features including laboratory test findings, high-resolution lung computed tomography data, treatment content, and complications such as infections and prognosis. We also examined clinical features between surviving and deceased patients in the older patient group. RESULTS: Of 40 enrolled patients, 13 were classified as old and 27 as young. Older patients had significantly fewer clinical symptoms including arthralgia/arthritis (p < .01), skin ulceration (p = .02), and higher mortality than younger patients (p = .02) complicated with rapidly progressive ILD (RP-ILD), combination immunosuppressive therapy, and strictly controlled infections. CONCLUSION: Clinical features and mortality of anti-MDA5 autoantibody-positive DM patients were influenced by age. Patients aged ≥60 years had a worse prognosis, and combination immunosuppressive therapy was often ineffective for RP-ILD in older patients.

A relapsing case of pulmonary-renal syndrome after a sequential rise in MPO-ANCA and anti-GBM antibodies.

A 69-year-old woman who presented with severe renal dysfunction and diffuse alveolar hemorrhage was diagnosed with pulmonary-renal syndrome (PRS) based on the coexistence of serum myeloperoxidase (MPO)-antineutrophil cytoplasmic antibodies (ANCA) and anti-glomerular basement membrane (GBM) antibodies (Ab). Hemodialysis was started; plasma exchange and intravenous methylprednisolone pulse therapy were administered followed by oral prednisolone administration. Pulmonary hemorrhage decreased; however, renal dysfunction persisted. On maintenance hemodialysis and prednisolone therapy, MPO-ANCA and anti-GBM Ab became negative at 4 and 10 months, respectively; thereafter, they became positive again at 18 and 35 months, respectively. At 36 months, there was relapse of pulmonary hemorrhage. Plasma exchange and intravenous methylprednisolone pulse therapy were administered; pulmonary hemorrhage ceased, and both antibodies became negative. It is known that PRS cases that are double positive for ANCA and anti-GBM Ab occasionally relapse after remission, and, even though they are double positive at initial diagnosis, most relapses occur with reappearance or re-elevation of ANCA but with absence of anti-GBM-Ab. Therefore, this was a rare relapsing case that presented with double-positive serology. Further, our observation that the reappearance of ANCA preceded that of anti-GBM-Ab suggests that ANCA contribute to the reproduction of anti-GBM Ab.