Interstitial pneumonia with autoimmune characteristics / features (IPAF) is a disease group with a combination of idiopathic interstitial pneumonia (IIP) and an underlying non-classified systemic connective tissue disease (reference: Fisher A, 2015 ). The condition is an example that collaboration between lung physicians and rheumatologists is useful in investigating and diagnosing.
There are no validated internationally accepted criteria for classification or diagnosis (per 2018), but the following seems to be agreed upon that three points must be met:
- Idiopatic interstital pneumonia (IIP) should be diagnosed on the basis of
- Systemic, non-classifiable connective tissue disease is diagnosed on the basis of at least two of three (A-C) and item 3. below:
- Other causes of disease must be ruled out by thorough clinical assessment
Disease symptoms from lungs vary from slightly increased breathing difficulties and / or dry coughs at physically heavy stress to severe lung failure
- Rheumatic symptoms can be joint- or muscle aches, Raynaud's phenomenon, rash, fever or symptoms from different organs
Treatment of IPAF
The lung changes at IPAF range from inflammation (rheumatic inflammation) to fibrosis with increased connective tissue. While inflammation can be treated with corticosteroids (Prednisone) and other immunosuppressive drugs, fibrosis is usually unaffected. It is recommended to assess treatment initiation if lung changes increase and include 20% or more of the lung tissue (at HRCT). The choice of drug is based on the assessment of the individual's disease course and is done by experienced doctors, most of whom are specialists in pulmonary diseases in consultation with rheumatology specialists. Medications that are often considered are:
- Corticosteroids (Solu-Medrol, Prednisone)
- Ciclosporin A
If the lung changes are the most serious manifestation of the disease, regular follow-up by a specialist of lung diseases is essential. HRCT investigations and pulmonary function tests, possibly supplemented with the 6 minute walk test is often used.
- Rheumatologists often contribute long experience with the immunosuppressive drugs and assessment of various manifestations of disease outside the lungs.