2.1 Tissue sampling
Twenty-two VKC patients (6 females, 16 males; mean age 10+3.5years) and
20 age, sex and ethnicity-matched healthy controls (HC) (7 females, 13
males; mean age 10+3.2 years) were recruited from the Ocular Allergy and
Pediatric Ophthalmology services of the University of Padua between
April 2019 and October 2019. Neither VKC patients nor healthy controls
had a history of ocular diseases (other than VKC), infection, surgery or
contact lens use. Diagnosis of VKC was based on the patient’s history
and presence of typical signs and symptoms (21). Type of VKC (tarsal,
limbal or mixed), positive skin prick test and/or presence of serum
allergen-specific IgE (IgE positive sensitization), and disease-specific
ongoing treatment (topical 1% cyclosporine A, antihistamines and/or
mast cell stabilizers) were recorded. All the healthy controls were free
from any topical and systemic treatment. None of subjects enrolled
received antibiotics, corticosteroids, or non-steroidal
anti-inflammatory drugs within 6 months (Table 1).
Each patient was swabbed at the inferior fornix of the right eye with a
single-use, dry, sterile nylon swab (eSwab, Copan diagnostics Inc.,
Murrieta, CA, USA), placed in 1 mL sterile liquid amies medium after use
and stored at -20°C until processing. All samples were collected by the
same expert operator (A.L.) by passing twice in the inferior fornix
avoiding touching the lid margin and without using topical anesthetic to
prevent any potential contamination. Each patient/parent was also
provided with a simple 10-items non-validated questionnaire
investigating the presence of some of the principal factors related to
allergy development including allergy family history, vaginal or
cesarean delivery, maternal breastfeeding and/or formula feeding,
weaning age, residence in an urban or rural area, varied or restricted
diet, atopic dermatitis within the first year of life, repeated and
prolonged contacts with pets, and family’s socioeconomic status. A
validated, disease-specific questionnaire, the Quality of Life in
Children with Vernal Keratoconjunctivitis (QUICK) questionnaire, was
administered only to VKC (25). The study was approved by the
Institutional Review Board and Local Ethical Committee, and adhered to
the tenets of the Declaration of Helsinki. Written informed consent was
obtained from a parent of all subjects enrolled.