Anti-Myxovirus Resistance Protein-1 Immunoglobulin A Autoantibody in Idiopathic Pulmonary Fibrosis.

Background: We have previously analysed serum autoantibody levels in patients with idiopathic pulmonary fibrosis (IPF), idiopathic nonspecific interstitial pneumonia (iNSIP), and healthy controls and identified the autoantibody against anti-myxovirus resistance protein-1 (MX1) to be a specific autoantibody in iNSIP. We found that a higher anti-MX1 autoantibody level was a significant predictor of a good prognosis in patients with non-IPF idiopathic interstitial pneumonias. In this retrospective study, we sought to clarify the prognostic significance of the anti-MX1 autoantibody in IPF. Methods: We measured anti-MX1 immunoglobulin (Ig) G, IgA, and IgM autoantibody levels by enzyme-linked immunosorbent assay in serum collected at the time of diagnosis from 71 patients with IPF diagnosed according to the 2018 IPF guideline. The gender-age-physiology (GAP) index was calculated in each case. Results: The study population (59 men and 12 women) had a median age of 67 years. Serum anti-MX1 IgG and IgA autoantibody levels correlated positively with GAP stage (p < 0.05). Univariate Cox proportional hazards regression analysis did not identify an elevated anti-MX1 IgG, IgA, or IgM autoantibody level as a significant prognostic factor; however, a higher anti-MX1 IgA autoantibody level heralded significantly poorer survival after adjustment for GAP stage (p=0.030) and for percent forced vital capacity and modified Medical Research Council score (p=0.018). Neither the anti-MX1 IgG autoantibody nor the IgM autoantibody could predict survival after these adjustments. Conclusions: The serum anti-MX1 IgA autoantibody level is a significant prognostic factor in IPF. Further studies are needed to clarify the pathophysiological role of this autoantibody in IPF.

Classification of idiopathic interstitial pneumonias using anti-myxovirus resistance-protein 1 autoantibody.

Chronic fibrosing idiopathic interstitial pneumonia (IIP) can be divided into two main types: idiopathic pulmonary fibrosis (IPF), a steroid-resistant and progressive disease with a median survival of 2-3 years, and idiopathic non-specific interstitial pneumonia (INSIP), a steroid-sensitive and non-progressive autoimmune disease. Although the clinical courses of these two diseases differ, they may be difficult to distinguish at diagnosis. We performed a comprehensive analysis of serum autoantibodies from patients definitively diagnosed with IPF, INSIP, autoimmune pulmonary alveolar proteinosis, and sarcoidosis. We identified disease-specific autoantibodies and enriched KEGG pathways unique to each disease, and demonstrated that IPF and INSIP are serologically distinct. Furthermore, we discovered a new INSIP-specific autoantibody, anti-myxovirus resistance-1 (MX1) autoantibody. Patients positive for anti-MX1 autoantibody constituted 17.5% of all cases of chronic fibrosing IIPs. Notably, patients rarely simultaneously carried the anti-MX1 autoantibody and the anti-aminoacyl-transfer RNA synthetase autoantibody, which is common in chronic fibrosing IIPs. Because MX1 is one of the most important interferon-inducible anti-viral genes, we have not only identified a new diagnostic autoantibody of INSIP but also obtained new insight into the pathology of INSIP, which may be associated with viral infection and autoimmunity.

Improvement of health status evaluated by Arthritis Impact Measurement Scale 2 (AIMS-2) and Short Form-36 (SF-36) in patients with rheumatoid arthritis treated with tocilizumab.

OBJECTIVE: To evaluate the improvement of health status in patients with rheumatoid arthritis (RA) treated with tocilizumab. METHODS: Thirty-nine patients were treated with 8 mg/kg tocilizumab every 4 weeks for 24 weeks. Disease activity was assessed by Clinical Disease Activity Index (CDAI) and Simplified Disease Activity Index (SDAI). Improvement of health status was assessed by Arthritis Impact Measurement Scale 2 (AIMS-2) and Short Form-36 (SF-36). RESULTS: Tocilizumab improved CDAI and SDAI significantly at week 4 compared with at baseline. In the components of AIMS-2, "physical score", "symptom" and "affect" improved significantly at week 4 compared with at baseline, while "social interaction" did not improve significantly during 24 weeks of tocilizumab therapy. Similarly in SF-36, "bodily pain", "general health", "vitality" and "mental health" improved significantly at week 4. The most correlative component of AIMS-2 with CDAI was "symptom", while "social interaction" did not correlate with CDAI during tocilizumab treatment. CONCLUSION: The time-course diversity in improvement of health status should be considered to provide proper healthcare when treated with tocilizumab.

A case report of a patient with rheumatoid arthritis complicated with Mycobacterium avium during tocilizumab treatment.

A female patient with rheumatoid arthritis (RA) suffered from Mycobacterium avium (M. avium) infection during tocilizumab treatment. Tocilizumab was discontinued and she was treated with a recommended chemotherapy, resulting in improvement of M. avium. Tocilizumab retreatment did not aggravate M. avium infection, and radiographic abnormalities improved over 1 year after cessation of the recommended therapy. Tocilizumab may be one candidate for intractable RA patients with M. avium if any biologic is required.

Masked early symptoms of pneumonia in patients with rheumatoid arthritis during tocilizumab treatment: a report of two cases.

Although reports of serious infections in clinical trials for rheumatoid arthritis (RA) with tocilizumab, anti-interleukin6 (IL-6) receptor antibody, have been relatively few, there is still some concern about infections. We report here two cases of patients who developed severe pneumonia during tocilizumab treatment for RA. Both patients initially presented with only minimal clinical symptoms and modest elevations in serum C-reactive protein. Tocilizumab might suppress the early inflammatory symptoms of pneumonia.