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

Table 1

Patient demographics.

Parameters	Frequency (%) or median (IQR)
Gender, male/female	59/12 (83.1/16.9)
Age, years	67 (61–72)
Smoking, y/n	62/9 (87.3/12.7)
Smoking, CS/EX/NS	15/47/9 (21.1/66.2/12.7)
Packyears
Current smoker	36 (27.75–50.00)
Ex-smoker	45 (32.25–67.13)
Diagnosis of IPF, Clinical/SLB	36/35 (50.7/49.3)
HRCT pattern^†, UIP/possible/inconsistent	46/21^‡/4^‡
BMI	24.9 (23.3–26.3)
mMRC, <2/2≤	48/23 (67.6/32.4)
FVC, %	76.5 (64.6–90.5)
DLco, %	51.1 (37.2–62.0)
GAP stage, I/II/III	33/32/4 (47.8/46.4/5.8)
KL-6, U/mL	849 (587–1203)
SP-D, ng/mL	178 (110–305)
Neutrophils in BAL, %	2.30 (0.80–6.00)
Lymphocytes in BAL, %	7.30 (3.40–12.4)
Prednisolone started before AE	16 (22.5%)
Prednisolone started after AE	17 (23.9%)
Immunosuppressants started before AE^§	11 (15.5%)
AZP/CyA/CPA	5/5/1
Immunosuppressants started after AE^§	9 (12.8%)
AZP/CyA/CPA	5/2/2
Pirfenidone started before AE	11 (15.5%)
Pirfenidone started after AE	0 (0%)
Occurrence of AE, yes/no	23/48 (32.4/67.6)
Observation period^#, days	1289 (516–1879)
Final outcome, alive/dead	39/32 (54.9/45.1)
Anti-MX1 IgG autoantibody	0.166 (0.129–2.400)
Anti-MX1 IgA autoantibody	0.124 (0.093–0.165)
Anti-MX1 IgM autoantibody	0.063 (0.046–0.091)
Anti-MX1 IgG autoantibody, >0.237	18 (25.4%)
Anti-MX1 IgA autoantibody, >0.312	4 (5.6%)
Anti-MX1 IgM autoantibody, >0.450	0 (0%)

CS, current smoker; ES, ex-smoker; NS, nonsmoker; IPF, idiopathic pulmonary fibrosis; SLB, surgical lung biopsy; HRCT, high-resolution computed tomography; UIP, usual interstitial pneumonia; BMI, body mass index; mMRC, modified Medical Research Council score for shortness of breath; FVC, forced vital capacity; DLco, diffusing capacity of carbon monoxide; KL-6, Krebs von den Lungen-6; SP-D, surfactant protein-D; AE, acute exacerbation; AZP, azathioprine; CyA, cyclosporine A; CPA, cyclophosphamide; MX1, myxovirus resistance protein-1; Ig, immunoglobulin. Number of patients: (n = 70), (n = 69), the other parameters (n = 71). ^§All patients treated with immunosuppressants underwent prednisolone therapy. None of the patients were treated with triple therapy using prednisolone, azathioprine, and N-acetylcysteine. ^#Days from diagnosis of IPF to death or last follow-up. All anti-MX1 IgA autoantibody-positive cases were included in the anti-MX1 IgG autoantibody-positive cases. ^†Median %FVC of IPF patients with UIP, possible UIP, and inconsistent with UIP patterns on HRCT was 76.1%, 83.1%, and 71.4%, respectively. There was no significant difference among the 3 groups by the Kruskal–Wallis test (). ^‡Patients with possible UIP pattern and inconsistent with UIP pattern on HRCT were diagnosed as IPF by histological findings of SLB specimens after the multidisciplinary discussion.