Baseline demographic, clinical, physiologic and BAL characteristics of the study groups as initially diagnosed

FVC: forced vital capacity; SpO2: oxygen saturation; BAL: bronchoalveolar lavage; HRCT: high resolution computed tomography.
*Normal values at Mexico City altitude: 67±3 mmHg.
**“Rapid” and “slow” progressors were compared with a T test for independent groups in case of continuous variables or with a chi square test or Fisheŕs exact test for count variables.