Nitrite, neopterin levels and tryptophan degradation in allergic conjunctivitis

PurposeThe study aims to evaluate changes in neopterin levels and tryptophan degradation which are induced by Th1-type immune response and nitric oxide metabolism which may be involved in allergic inflammation.MethodsSerum nitrite, kynurenine, tryptophan and neopterin levels were evaluated in 36 patients with seasonal allergic conjunctivitis, along with these values in 41 healthy subjects. All these parameters have been compared with symptom and sign scores.ResultsTryptophan and kynurenine concentrations were not significantly changed, while serum nitrite concentrations were significantly low, and neopterin levels were significantly increased in patients compared to healthy subjects (p<0.05). There was a significant relationship between symptom scores and serum nitrite levels in patients.ConclusionsThis preliminary study demonstrates that serum nitric oxide metabolism might have a role in allergic conjunctivitis. Serum neopterin levels but not tryptophan metabolism could serve as a biomarker in patients with seasonal allergic conjunctivitis.