Sarcoidosis and Immune Cells in Lung, Lymph Nodes and Blood

Background:

Sarcoidosis is an inflammatory disease, most commonly affecting the lungs and intrathoracic lymph nodes but can affect virtually any organ, sometimes manifesting as life threatening cardiac arrythmias. Some patients resolve spontaneously, whereas others get a chronic disease leading to for instance impaired lung function and cardiac failure. The most severe cases might need a transplantation.

In the lungs, activated T cells are accumulated leading to release of cytokines, especially TNF-alpha is regarded as crucial for disease progression. Some segments of the T cell receptor and specific genes (HLA types) are connected to a resolving disease. More detailed knowledge about mechanisms why some experience a chronic disease course and others resolve spontaneously without treatment is to a large extent lacking. There is no cure, and despite treatment with immunosuppressants (often corticosteroids and cytotoxic agents), many patients experience a deteriorating disease.

Aim:

1. Find biomarkers to be able to early predict which patients will develop a more severe/ chronic disease course and thereby enabeling early intervention before irreversible damage. 2. Predict which treatment is best for a specific patient, i.e. individualize treatment. 3. Find targets for new potential therapies.

Methods:

The majority of data is collected at investigations normally performed during diagnostic work-up for sarcoidosis. Most patients undergo a bronchoscopy with bronchoalveolar lavage (BAL) and some also lymph node punction through oesophagus with the help of ultrasound. The BAL fluid that remains after clinical analysis is used for research purpose. For patients undergoing lymph node punction, one extra punction is performed for research purpose. Extra blood samples are taken from all patients.

The samples will mostly be used for studying T cells with immunohistochemistry, flow cytometry including activity markers, subtypes and receptors, but also cytokines and other cells (for instance B cells, NK and NKT cells). The patients are followed longitudinally, minimum 2 years. Some patients will undergo a second bronchoscopy 6-12 months after the first. Results from the immunological investigations will be correlated to disease course, genetics and result of treatment.

Significance :

By comparing the inflammation in several compartments (lung, lymph node , blood) at a molecular level with clinical disease course, genotype, and treatment response we hope to find biomarkers that can predict disease course and response to therapy. Thereby, we hope to be able to tailor therapy for each individual patient. By studying several compartments, the results may also help to improve understanding of how a systemic inflammation is distributed within the body, and thus also contribute to understanding of other inflammatory diseases.