Patients with idiopathic pulmonary fibrosis with antibodies to heat shock protein 70 have poor prognoses.

RATIONALE: Diverse autoantibodies are present in most patients with idiopathic pulmonary fibrosis (IPF). We hypothesized that specific autoantibodies may associate with IPF manifestations. OBJECTIVES: To identify clinically relevant, antigen-specific immune responses in patients with IPF. METHODS: Autoantibodies were detected by immunoblots and ELISA. Intrapulmonary immune processes were evaluated by immunohistochemistry. Anti-heat shock protein 70 (HSP70) IgG was isolated from plasma by immunoaffinity. Flow cytometry was used for leukocyte functional studies. MEASUREMENTS AND MAIN RESULTS: HSP70 was identified as a potential IPF autoantigen in discovery assays. Anti-HSP70 IgG autoantibodies were detected by immunoblots in 3% of 60 control subjects versus 25% of a cross-sectional IPF cohort (n = 122) (P = 0.0004), one-half the patients with IPF who died (P = 0.008), and 70% of those with acute exacerbations (P = 0.0005). Anti-HSP70 autoantibodies in patients with IPF were significantly associated with HLA allele biases, greater subsequent FVC reductions (P = 0.0004), and lesser 1-year survival (40 ± 10% vs. 80 ± 5%; hazard ratio = 4.2; 95% confidence interval, 2.0-8.6; P < 0.0001). HSP70 protein, antigen-antibody complexes, and complement were prevalent in IPF lungs. HSP70 protein was an autoantigen for IPF CD4 T cells, inducing lymphocyte proliferation (P = 0.004) and IL-4 production (P = 0.01). IPF anti-HSP70 autoantibodies activated monocytes (P = 0.009) and increased monocyte IL-8 production (P = 0.049). ELISA confirmed the association between anti-HSP70 autoreactivity and IPF outcome. Anti-HSP70 autoantibodies were also found in patients with other interstitial lung diseases but were not associated with their clinical progression. CONCLUSIONS: Patients with IPF with anti-HSP70 autoantibodies have more near-term lung function deterioration and mortality. These findings suggest antigen-specific immunoassays could provide useful clinical information in individual patients with IPF and may have implications for understanding IPF progression.

Severe Pulmonary Arterial Hypertension in Healthy Young Infants: Single Center Experience.

OBJECTIVE: We studied the clinical presentation and management of acute pulmonary arterial hypertension (PAH) in healthy young infants, and the effect of thiamine therapy. METHODS: Review of hospital records was conducted for 56 healthy infants (aged below 6 month) who developed sudden onset of pulmonary arterial hypertension as diagnosed on 2D echocardiography, and were admitted at our institution. RESULTS: All patients received supportive care and pulmonary vasodilator therapy, whereas those admitted after Sep-tember, 2019 (n=28) received thiamine in addition, as per the institute's protocol. Overall, complete recovery was seen in 80% (n=45). Infants who died had significantly lower mean pH (7.05 vs 7.27; P=0.001) and serum bicarbonate (9.1 vs 14.9; P=0.007), higher arterial lactate (72.7 vs 61.5; P=0.92), ventricular dysfunction (16 vs 10; P=0.01) and shock (7 vs 9; P=0.008) when compared to those who survived. Baseline characteristics, severity of acidosis and pulmonary hypertension, time taken to recover from PAH, presence of ventricular dysfunction were comparable among those who received thiamine and those who did not receive it. Similarly, recovery (89% vs 71%; P=0.17) and mortality (11% vs 29%) were also comparable between the two groups. CONCLUSIONS: A significant proportion of infants with PAH improve with supportive treatment and pulmonary vasodilator therapy. Thiamine supplementation may not give any additional benefit in these patients.