[The clinical features and prognosis of interstitial lung disease patients with positive anti-neutrophil cytoplasmic antibody]

Objective: To investigate the clinical features and prognosis of interstitial lung disease patients with positive anti-neutrophil cytoplasmic antibody. Methods: The patients with interstitial lung disease who visited Peking Union Medical College Hospital from March 2006 to March 2016 were divided into three groups: interstitial lung disease with ANCA-positive(ANCA-ILD), connective tissue disease associated interstitial lung disease and interstitial pneumonia with autoimmune features (CTD-ILD/IPAF) and idiopathic interstitial pneumonia (IIP). The three groups were analyzed in terms of clinical manifestations, serology, lung function, imaging, survival and recurrence. Results: Two hundred and seventy four patients were enrolled and 38 (14%) were ANCA-positive of whom 16 were male and 22 were female. The age of 38 ANCA-positive patients was (59±10) years and the follow-up time was (52±31) months. Seven among the 38 ANCA-positive patients died and the death rate is 18.42%. The ANCA-positive patients with interstitial lung disease have higher onset age (ANCA-ILD:59±10,CTD-ILD/IPAF:52±10,IIP:53±11,H=19.29, P<0.001), lower hemoglobin (ANCA-ILD: 129±21, CTD-ILD/IPAF: 138±15, IIP: 140±19, H=8.17, P=0.017), higher erythrocyte sedimentation rate (ANCA-ILD:45±35, CTD-ILD/IPAF:26±24,IIP:19±22,H=19.73, P<0.001), lower lung function improvement rate after treatment (ANCA-ILD:31%,CTD-ILD/IPAF:59%,IIP: 39%,χ(2)=11.74,P=0.003), lower absorption rate of CT lesion (ANCA-ILD:61%,CTD-ILD/IPAF:82%,IIP:67%, χ(2)=9.23,P=0.010) and higher death rate(ANCA-ILD:18%,CTD-ILD/IPAF:6%,IIP:12%, χ(2)=7.16,P=0.028). Conclusions: There are significant differences in clinical characteristics between ANCA-positive patients and other types of pulmonary interstitial disease. And both the treatment effect and the prognosis is poor for the ANCA-positive patients.

Clinical Features of Idiopathic Interstitial Pneumonia with Systemic Sclerosis-Related Autoantibody in Comparison with Interstitial Pneumonia with Systemic Sclerosis

Background

Patients with idiopathic interstitial pneumonias sometimes have a few features of connective tissue disease (CTD) and yet do not fulfil the diagnostic criteria for any specific CTD.

Objective

This study was conducted to elucidate the characteristics, prognosis, and disease behavior in patients with interstitial lung disease (ILD) associated with systemic sclerosis (SSc)-related autoantibodies.

Methods

We retrospectively analyzed medical records of 72 ILD patients: 40 patients with SSc (SSc-ILD) and 32 patients with SSc-related autoantibody-positive ILD but not with CTD (ScAb-ILD), indicating lung-dominant CTD with SSc-related autoantibody.

Results

Patients with SSc-ILD were predominantly females and non-smokers, and most had nonspecific interstitial pneumonia confirmed by high-resolution computed tomography (HRCT) and pathological analysis. However, about half of the patients with ScAb-ILD were male and current or ex-smokers. On HRCT analysis, honeycombing was more predominant in patients with ScAb-ILD than with SSc-ILD. Pathological analysis showed the severity of vascular intimal or medial thickening in the SSc-ILD patients to be significantly higher than that in the ScAb-ILD patients. Survival curves showed that the patients with ScAb-ILD had a significantly poorer outcome than those with SSc-ILD.

Conclusion

Data from this study suggest that lung-dominant CTD with SSc-related autoantibody is a different disease entity from SSc-ILD.

Clinical Utility of an Enzyme-Linked Immunosorbent Assay for Detecting Anti-Melanoma Differentiation-Associated Gene 5 Autoantibodies

Objective

Autoantibodies to melanoma differentiation-associated gene 5 (MDA5) are specifically expressed in patients with dermatomyositis (DM) and are associated with a subset of DM patients with rapidly progressive interstitial lung disease (RP-ILD). Here, we examined the clinical utility of a newly developed enzyme-linked immunosorbent assay (ELISA) system for detecting these antibodies.

Methods

Here we developed an improved ELISA for detecting anti-MDA5 antibodies. We then performed a multicenter clinical study involving 8 medical centers and enrolled 242 adult patients with polymyositis (PM)/DM, 190 with non-PM/DM connective tissue disease (CTD), 154 with idiopathic interstitial pneumonia (IIP), and 123 healthy controls. Anti-MDA5 antibodies in the patients’ serum samples were quantified using our newly developed ELISA, and the results were compared to those obtained using the gold-standard immunoprecipitation (IP) assay. In addition, correlations between the ELISA-quantified anti-MDA5 antibodies and clinical characteristics were evaluated.

Results

In patients with PM/DM, the anti-MDA5 antibody measurements obtained from the ELISA and IP assay were highly concordant; the ELISA exhibited an analytical sensitivity of 98.2%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 99.5% (compared to the IP assay). Anti-MDA5 antibodies were detected in 22.7% of the DM patients, but not in any of the patients with PM, non-PM/DM CTD, or IIP. Clinically amyopathic DM, RP-ILD, arthritis, and fever were more prevalent in DM patients who were anti-MDA5 antibody-positive than in those who were antibody-negative (P ≤ 0.0002 for all comparisons). In addition, anti-MDA5 antibody-positive patients with RP-ILD exhibited higher antibody levels than those without RP-ILD (P = 0.006).

Conclusion

Our newly developed ELISA can detect anti-MDA5 antibodies as efficiently as the gold standard IP assay and has the potential to facilitate the routine clinical measurement of anti-MDA5 antibodies in patients who suspected to have DM.

Coexistence of Autoantibodies against the Golgi Complex and Ro52 Antigen in a Patient with Nonspecific Interstitial Pneumonia

Nonspecific interstitial pneumonia (NSIP) is often associated with connective tissue diseases (CTD). The diagnosis of NSIP was confirmed in a 63-year-old man by high-resolution computed tomography and an open lung biopsy. Anti-Golgi complex autoantibodies (AGA) and anti-Ro52 antibodies were simultaneously detected at high concentrations. Autoantibodies to aminoacyl-tRNA synthetases (ARS) were negative. The patient was treated with corticosteroids for six months. During the seven-year follow-up, NSIP had a slow progression and patient had not developed the clinical features of CTD. The present study potentially demonstrates that the autoimmune process elicited by AGA and/or Ro/SSA may play a role in promoting idiopathic NSIP independently of the typical ARS routes, which has not been reported thus far.

The pandemic influenza A (H1N1) 2009 vaccine does not increase the mortality rate of idiopathic interstitial pneumonia: a matched case-control study

Background

Evidence regarding the mortality rate after administration of the pandemic influenza A (H1N1) 2009 vaccine on patients with underlying diseases is currently scarce. We conducted a case-control study in Japan to compare the mortality rates of patients with idiopathic interstitial pneumonia after the vaccines were administered and were not administered.

Methods

Between October 2009 and March 2010, we collected clinical records in Japan and conducted a 1∶1 matched case-control study. Patients with idiopathic interstitial pneumonia who died during this period were considered case patients, and those who survived were considered control patients. We determined and compared the proportion of each group that received the pandemic influenza A (H1N1) 2009 vaccine and estimated the odds ratio. Finally, we conducted simulations that compensated for the shortcomings of the study associated with adjusted severity of idiopathic interstitial pneumonia.

Results

The case and control groups each comprised of 75 patients with idiopathic interstitial pneumonia. The proportion of patients who received the pandemic influenza A (H1N1) 2009 vaccine was 30.7% and 38.7% for the case and control groups, respectively. During that winter, the crude conditional odds ratio of mortality was 0.63 (95% confidence interval, 0.25–1.47) and the adjusted conditional odds ratio was 1.18 (95% confidence interval, 0.33–4.49); neither was significant. The simulation study showed more accurate conditional odds ratios of 0.63–0.71.

Conclusions

In our study, we detected no evidence that the influenza A (H1N1) 2009 vaccine increased the mortality rate of patients with idiopathic interstitial pneumonia. The results, however, are limited by the small sample size and low statistical power. A larger-scale study is required.

Nonspecific interstitial pneumonia (NSIP) associated with anti-KS antibody: differentiation from idiopathic NSIP

We report two cases of biopsy-proven nonspecific interstitial pneumonia (NSIP) with anti-KS (asparaginyl-tRNA) antibody. Anti-KS antibody is the sixth anti-aminoacyl-tRNA synthetase (ARS) antibody. They showed interstitial pneumonia without clinical symptoms, and high resolution computed tomography (HRCT) of the chest demonstrated consolidation along bronchovascular bundles and volume loss in the bilateral lower lobes, which were suggestive of connective tissue diseases (CTD). One case of cellular NSIP responded to corticosteroid, but the other case of fibrotic NSIP required corticosteroid and cyclosporin. In patients with these HRCT findings, the measurement of anti-ARS antibodies could be helpful even in the absence of clinical symptoms suggestive of CTD.

Two types of myeloperoxidase-antineutrophil cytoplasmic autoantibodies with a high affinity and a low affinity in small vessel vasculitis

OBJECTIVE

Myeloperoxidase (MPO) -anti-neutrophil cytoplasmic autoantibodies (ANCAs) are detected at a high rate in microscopic polyangiitis and renal-limited vasculitis. MPO-ANCA titers are not always reflected in the disease activity. We studied the titer and affinity of MPO-ANCA in sera from patients in relation to vasculitis activity.

METHODS

Blood samples were collected from 27 newly diagnosed or relapsed patients with MPO-ANCA-associated vasculitides. The MPO-ANCA titer was determined by a direct enzyme-linked immunosorbent assay (ELISA) using homogeneously purified human MPO of leukocytes. The MPO-ANCA affinity was expressed as IC50 that was determined by a competitive inhibition method using the ELISA.

RESULTS

The MPO-ANCA affinity of 27 sera from 27 patients could be classified into a high-affinity type (14 sera) and a low-affinity type (13 sera). The mean values for IC50 in the two types were 0.15+/-0.06 microg/ml and 0.54+/-0.15 microg/ml, and the difference was statistically significant (p<0.0000000684). Between the two groups of patients divided by the affinity, there were differences in the Birmingham Vasculitis Activity Score (BVAS): and in C-reactive protein (CRP): (p<0.00093 and p<0.00129, respectively). However, the difference in titer was not statistically significant (p<0.0265). The affinity remained steady from the disease onset to remission or relapse.

CONCLUSIONS

The affinity of MPO-ANCA from patients with MPO-ANCA-associated vasculitides were largely distinguished into a high and a low affinity, irrespective of the level of MPO-ANCA titers, and may be helpful for assessment of vasculitis activity affecting mainly the kidney and the lung.