Abstract
Purpose:
Sarcoidosis is an important cause of intraocular inflammation (uveitis) with very variable clinical presentation. Therefore, it is a clinical diagnosis that has to be supported by laboratory testing (pathology and serology).The most commonly used serological marker is angiotensin converting enzyme (ACE). In this study we analyzed additional markers (lysozyme and soluble Interleukin-2 Receptor: sIL-2R) that are associated with sarcoidosis and compared their single and combined values to predict pulmonary involvement that can confirm the diagnosis of ocular sarcoidosis.
Methods:
ACE, lysozyme and sIL-2Rlevels have been determined in the serum of patients with noninfectious uveitis that was compatible with sarcoidosis. Patients (n=36) with elevation of at least one parameter have been classified according to the diagnostic criteria from the International Workshop on Ocular Sarcoidosis, Tokyo, 2006. Patients were further subdivided into groups with pulmonary involvement (biopsy proven: n=10, hilar lymphadenopathy: n=2) or without (n=24). Sensitivity, specificity and Youden index have been calculated to predict pulmonary sarcoidosis of single and combined serological values. None of the patients had been treated with ACE-inhibitors or systemic steroids.
Results:
ACE as a single parameter revealed a lower sensitivity (0.50) than sIL-2R (0.83) or lysozyme (0.83), whereas the specificity was higher in ACE alone (0.88) than in sIL-2R (0.54) or lysozyme (0.50). The combination of ACE and sIL-2R demonstrated the highest Youden index (0.46) with a sensitivity of 0.50 and a specificity of 0.96, followed by the combination of ACE, sIL-2R and lysozyme (Youden index 0.42, sensitivity 0.42, specificity 1.00). Lysozyme combined with sIL-2R showed a Youden index of 0.38, a sensitivity of 0.67, and a specificity of 0.71, better than both values alone.
Conclusions:
In contrast to the current practice with testing for ACE as a single marker, we propose a combination of ACE and sIL-2R as the standard serology to screen for sarcoidosis in uveitis patients. In patients that take ACE-inhibitors, ACE should be replaced by lysozyme. The combination of ACE and sIL-2R is the most reliable predictor of pulmonary involvement in ocular sarcoidosis.
Keywords: 557 inflammation •
467 clinical laboratory testing