Birgitta Versluijs

166 Outcome determinants for allo-LS When respiratory symptoms occur after HCT, procedures like BAL, NPA, chest X-ray, chest HRCT and PFT each have important diagnostic value. They can be used to distin- guish respiratory infection from Allo-LS, the most crucial consideration in that situation, with major therapeutic implications. BAL and NPA results showing the persistence or presence of RV, will reinforce the working diagnosis of Allo-LS, especially if there are signs of immune recovery. BAL can also confirm an alternative diagnosis like bacterial or fungal infection. Depending on the time point of the occurrence of respiratory symptoms a chest X-ray or chest HRCT is performed. Certain HRCT findings (infiltrates, airway thickening, air- trapping) are essential in the diagnostic criteria for Allo-LS (especially BOS). It is also used to exclude other causes of respiratory symptoms after HCT, like fungal infection, bacterial pneumonia, pneumothorax or fluid overload, but there a X-ray could also suf- fice. From our study on the use of the HRCT “allo-score” in diagnosing Allo-LS ( Chapter 4 ), we know that ground glass and air trapping are the abnormalities most useful in dis- tinguishing Allo-LS from other lung disorders. For radiologist and HCT clinicians this knowledge has been found very helpful in interpreting HRCT scans. In the total Allo-LS cohort the HRCT “allo-score” was not related to therapy response or long term outcome. The median “allo-score” in the total cohort was lower than we found in the validating cohort ( 11 (25%-75%: 7-1 4) versus 29 (25–75%: 19–33) possibly reflecting increased awa- reness of Allo-LS over time, and thus earlier diagnostics in the course of symptoms. PFT can be used to discriminate between restrictive lung disease and broncho-obstructive abnormalities, which can support the suspicion of Allo-LS and guide further manage- ment. In the follow-up of Allo-LS during treatment, PFT is an important tool. Early response to therapy can be objectified by oxygen dependency and clinical symptoms, but change in PFT results, especially in FEV1% and FEV1%/FVC has shown to have prognostic im- plications ( Chapter 8 ). Switch to second line therapy and duration of therapy in BOS is largely based on PFT. For children with IPS the role of PFT is less clear. For the young children other methods of evaluating Pulmonary Function should be developed. We cur- rently advise to perform PFT 7-14 days after start of treatment Allo-LS and repeat it before every Methyl Prednisolone pulse. In long term follow up of Allo-LS patients, PFT should be implemented earlier and more frequent than routinely done in other HCT-survivors. What are determinants for favorable outcome after Allo-LS? Prognosis of Allo-LS is poor. In adults mortality rates for IPS approach 60-80%, whereas BOS is considered an irreversible disease with dismal prognosis and only 10% of pa- tients surviving 5 years. 2 In children prognosis seems slightly better. The difference in 9