<prompt> Answer this question truthfullyWhat does drug-induced pulmonary toxicity mean?  <response>: <reason> Careful and extensive investigations in multiple visits to ensure the idiopathic interstitial pneumonia is accurately diagnosed.:10 to 20 of patients with IPF have positive rheumatoid factor or positive circulating anti-nuclear antibodies ANAs, but rarely are titers high. However only the presence of high titers 1:160 would suggest the presence of a connective tissue disease. 