Longstanding hypersensitivity pneumonitis and its response to roflumilast: A review of its likely immunological effects

We describe the case of a 42yr old man with evidence of hypersensitivity pneumonitis referred with cough and breathlessness for several years which had further deteriorated in the prior 12 months. He had known atopic asthma without evidence of activation. A chest CT scan showed widespread ground glass change in his lung fields. He had feather bedding at home and in his youth cleaned aviaries. His forced vital capacity and lung volumes were reduced along with oxygen saturations at rest (92% on air), overnight (83% on air) and upon walking (78%). Steroids were commenced for a total of 6 months with little consistent improvement in symptoms or objective measures and with no change in his CT scan appearance. As a result, a trial of roflumilast (a phosphodiesterase-4 inhibitor) was commenced due to its range of immunological effects and in order to avoid long-term immune suppression with mycophenolate motefil in a young patient. On roflumilast treatment his cough and breathlessness improved at 4 weeks and the chest crackles cleared. An interval Chest CT scan showed resolution of the ground glass change with improved CT scores that are maintained 2 yrs. All oxygen measures improved and nocturnal oxygen was discontinued. His Lung function has remained largely stable on roflumilast and symptoms of cough and breathlessness have resolved. This case report reviews the immunology of hypersensitivity pneumonitis and the likely actions of Roflumilast relevant to this condition. It is the first published case report documenting its use in hypersensitivity pneumonitis.