The study looked at eye tissue from people with a growth called pterygium and compared it to normal eye tissue. It found that a protein called HBD‑2 was present in many of the pterygium samples but not in normal tissue, while another protein, LL‑37, was not found in either group.

To investigate human beta-defensins (HBDs) and cathelicidin LL-37 (LL-37) expressions in patients with pterygium. In this retrospective consecutive case series, 26 pterygium specimens and 15 normal conjunctival specimens of 15 control subjects were in vestigated. Expressions of HBD-1, HBD-2, HBD-3, and LL-37 were assessed using immuno histochemical staining. A brown color in the cytoplasm and/or nuclei of epithelial cells indicated positive staining for HBDs and LL-37. For each antibody, the intensity of the reaction (negative [-], weak [1+], moderate [2+], or strong [3+]) was determined to describe the immunoreactions. The median age was 52 years in both groups. There were no significant differences in age and sex between the groups (p=0.583, p=0.355, respectively). Of the 26 pterygium specimens, 15 (57.7%) (14 weak, 1 moderate staining) showed HBD-2 expression, which was not observed in any of the control specimens. One (3.8%) pterygium and one (6.7%) control specimen demonstrated weak staining for HBD-3. HBD-2 expression was significantly higher in the pterygium specimens than in the controls (p=0.002). None of the tissue specimens had positive staining for HBD-1 or LL-37 in either group (both; p=1.00). HBD-2 expression was higher in pterygium specimens than in the controls. HBD-2 expression that might be stimulated by inflammatory cytokines may be related to inflammation and fibrovascular proliferation and may play a role in pterygium pathogenesis.