Abstract
Introduction: Pulmonary langerhans cell histiocytosis (PLCH) is a rare idiopathic pulmonary disease. Langerin, CD1a and S-100 have been proposed as immunohistochemical markers to identify Langerhans cells (LCs) in PLCH, but there are limited data on the role of langerin as a selective marker in detecting LCs.
Aims: To evaluate the role of CD1a, S-100 and langerin as diagnostic markers in the detection of LCs.
Methods: Formalin fixed paraffin embedded lung resections were collected from patients with PLCH and compared with tissue from control patients. Tissue immunoreactivity was assessed using CD1a, S-100, and langerin by automated immunohistochemistry, using a scoring system to characterise each diagnostic marker. Data are described using descriptive statistics, and compared using the chi-squared test.
Results: 36 cases (17 PLCH, 19 controls) were tested. Langerin was moderately or strongly expressed in 17 (100%) and 7 (37%) of patients in the PLCH and control group respectively (p<0.0001). More patients in the PLCH group had strong staining for Langerin (n=13, 76%) compared with CD1a (n=4, 24%) and S-100 (n=1, 6%) (p<0.001). In contrast, the number of patients with strong staining in the control group was similar between each of the markers (p=0.53).
Conclusion: Langerin may be a more useful marker, compared with CD1a and S-100, in identifying PLCH. Further research and a cost analysis are needed to evaluate whether langerin should replace CD1a and S-100 as a diagnostic test for PLCH.
Table one: Assessment of staining in PLCH patients
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