CO15 - Pulmonary Hypertension in Pulmonary Langerhans Cell Histiocytosis: Insights from 71 Patients
Ramdeep Bajwa (UK)1; Amira Benattia (France)2; Carmel Stock (UK)1; Manuel Lopez Meseguer (Spain)3; Effrosyni Manali (Greece)4; Berta Saez-Gimenez (Spain)3; Cormac McCarthy (Ireland)5; Donal O'Malley (Ireland)5; Frantzeska Frantzeskaki (Greece)4; Ioannis Tsagkaris (Greece)4; Elzbieta Radzikowska (Poland)6; Claudia Ravaglia (Italy)7; Roberto Cassandro (Italy)8; Davide Elia (Italy)8; Spyridon Papiris (Greece)9; Venerino Poletti (Italy)7; Sergio Harari (Italy)8; Laura Price (UK)1; Abdellatif Tazi (France)2; Athol Wells (UK)1; Maria Kokosi (UK)1;
1 - Royal Brompton Hospital, London; 2 - Hopital Saint Louis, Paris; 3 - Vall d'Hebron University Hospital; 4 - University Hospital Attikon, Athens; 5 - St Vincent's University Hospital, Dublin; 6 - 7National Tuberculosis and Lung Diseases Research Institute, Warsaw; 7 - GB Morgagni Hospital, Forli; 8 - UO di Pneumologia e Terapia Semi-Intensiva Respiratoria, Milan; 9 - National and Kapodistrian University of Athens;
Keywords: pulmonary hypertension; rare diseases; histiocytosis;
Select the theme: Rare diseases
Type: Original Papers
Presentation: Oral Communication

Introduction: Precapillary pulmonary hypertension (PH) is a recognised complication of pulmonary Langerhans cell histiocytosis (PLCH) and is associated with increased mortality. However, the underlying mechanisms remain poorly understood, and the efficacy of PH-targeted therapies is not well established.

Objectives: To characterise the clinical features and outcomes of patients with PLCH-associated PH.

Materials and Methods: We conducted a retrospective multicentre study across eight European expert centres, including patients with PLCH who underwent diagnostic right heart catheterisation (RHC). Data collected included demographics, pulmonary function tests (PFTs), haemodynamic parameters, and treatment details. Outcomes were lung transplantation and all-cause mortality.

Results: Seventy-one patients (42 male) were included, with a mean age of 61.6 years (SD 7) at PH diagnosis. All had a history of smoking. The median interval between PLCH and PH diagnosis was 3.5 years (IQR 0–13).

Baseline median (IQR) RHC values were: mean pulmonary arterial pressure (mPAP) 36 (29–44) mmHg, pulmonary arterial wedge pressure (PAWP) 9 (8–11) mmHg, cardiac output 4.8 (4.3–5.7) L/min, and pulmonary vascular resistance (PVR) 5.9 (3.9–8.4) Wood units.

At PH diagnosis, median (IQR) PFTs were: FEV₁ 58% (35–71), FVC 74% (56–84), DLCO 27% (21–31), KCO 34% (27–44), and RV 136% (93–193).

Twenty-four patients received pulmonary vasodilator therapy. Repeat RHC was performed in 34 patients after a median of 1 year (IQR 0.5–2.7), including 14 treated patients. Treated individuals showed significant improvement in mPAP (p=0.0001) and PVR (p=0.037) compared with untreated patients.

During follow-up, 66.2% of patients died or underwent lung transplantation


Conclusions: PLCH-associated PH is severe and carries a high mortality risk. In selected patients, pulmonary vasodilators appear safe and may improve haemodynamics. Further studies are needed to refine risk stratification and optimise management.