Preliminary evidence of the efficacy of probiotic eye-drop treatment in patients with vernal keratoconjunctivitis.

Background: Probiotics have been shown to improve allergic inflammation. The aim of this study was to evaluate the efficacy of Lactobacillus Acidophilus eye-drops in controlling signs and symptoms of vernal keratoconjunctivitis (VKC).
Methods: Seven patients (mean age 11.8 +/- 4.3; five M, two F) with mild to moderate VKC were included in the study. Lactobacillus Acidophilus diluted in saline solution (2 x 10(8) CFU/ml) was administrated as eye-drops four times daily for 4 weeks in both eyes. Clinical signs (conjunctival hyperemia, chemosis, secretion, Trantas dots, superficial punctuate keratitis) and symptoms (itching, photophobia, burning, tearing) were evaluated and scored from 0 to 3 at baseline, after 2 and 4 weeks of treatment. Total sign (TSS) and symptom (TSyS) scores were calculated. Conjunctival impression cytology was performed in three patients at baseline and after 4 weeks of treatment, in order to evaluate the expression of ICAM-1 and TLR-4.
Results: In the six out of seven patients who completed the study, symptoms were significantly improved after both 2 weeks (TSyS: baseline 6.7 +/- 0.9 vs 4.1 +/- 1.2; p = 0.017) and 4 weeks (TSyS: baseline 6.7 +/- 0.9 vs 3.6 +/- 1.2, p = 0.011) of treatment. A significant improvement of clinical signs was observed after 4 weeks of treatment (TSS: baseline 7.5 +/- 1.6 vs 3.9 +/- 1.7, p = 0.034) but not after 2 weeks of treatment (TSS: baseline 7.5 +/- 1.6 vs 5.3 +/- 1.5; NS). In particular, photophobia was significantly reduced (2 +/- 0.6 vs 1 +/- 0.3; p = 0.023) at 2 weeks, while at 4 weeks the scores for itching (1.8 +/- 0.3 vs 1 +/- 0.3), tearing (1.6 +/- 0.4 vs 0.8 +/- 0.2), conjunctival hyperemia (2.3 +/- 0.2 vs 1.4 +/- 0.5) and chemosis (1.2 +/- 0.4 vs 0.4 +/- 0.4) were significantly lower compared to baseline. A down-regulation of ICAM-1 and TLR-4 was observed in two patients showing clinical improvement after 4 weeks of treatment.
Conclusion: Our open pilot study showed that 1-month treatment with probiotic eye-drops improves signs and symptoms in patients with VKC. Additional double-blind controlled clinical trials with a larger sample of patients are needed to confirm the effects of topical Lactobacilli on VKC patients.