Identification of multiple potential triggers in sarcoidosis patients

Sarcoidosis is a systemic disorder of unknown etiology. The majority of
patients is between 20 and 40 years of age. In general the disease has a
favourable course, with spontaneous remission in 70% of patients within 3 years
from diagnosis. In the remaining group of patients, the disease can become
chronic, and will be fatal in approximately 5% of patients. An important
characteristic of the disease are non-caseating granulomas. So far, the cause
of the disease is unknown. Many potential organic/anorganic substances or
microorganisms have been suggested to trigger sarcoidosis such as aluminium,
beryllium, zirconium, mycobacteria and propionibacteria.

Long term exposure to beryllium can cause berylliosis, which is difficult to
distinguish from sarcoidosis. It has already been demonstrated in several
studies that some berylliosis patients were initial incorrectly diagnosed with
sarcoidosis. An interesting hypothesis might be that berylliosis is a type of
sarcoidosis in which the inducing antigen is known. The estimated mortality of
berylliosis is 25%, which is far higher compared to sarcoidosis. In The
Netherlands, no information is available about the eventual prevalence of
berylliosis among the group of sarcoidosis patients.

Currently, no curative treatment is available for sarcoidosis. Routine testing
for possible triggers in sarcoidosis is not daily clinical practice. However,
published data suggest that possible triggers could be identified in 74% of
patients. Conformation of these data in Dutch patients can lead the way for
randomized controlled trials in distinct subgroups of patients assessing the
efficacy of antimycobacterial or antipropionbacterial treatment. If
sensitization for metals in sarcoidosis patients can be determined, avoiding
exposure is an important extra therapeutic option in treating their disease.

To determine the prevalence of mycobacterial, propionibacterial and beryllium,
aluminium and zirconium sensitized patients within a well-defined Dutch cohort
of biopsy proven sarcoidosis patients.
New clinico-pathological phenotypes within the group of sarcoidosis patients
will be defined, using the data on sensitization in combination with a 4 year
follow up in order to define the Clinical Outcome Score (COS) after 2 and 4
years of follow up.

In addition, a comparison will be made between the classic lymphocyte
proliferation test and interferon gamma release assay in detecting metal
sensitization

Retrospective and prospective cohort study

Burden and risks are minimal due to the fact that vein puncture is the only
invasive proceidure during the study.