1. INTRODUCTION
Allergic diseases have dramatically risen over the last few
decades.1 Allergic conjunctivitis (AC) is one of the
most common ocular surface disorders that encompasses a spectrum of
diseases featured by antigen-specific immunoglobulin E (IgE) and T
helper type 2 (Th2) lymphocyte-mediated hypersensitivity
responses.2 Among different types of AC, seasonal
allergic conjunctivitis (SAC) and perennial allergic conjunctivitis
(PAC) represent the majority of cases. SAC and PAC share similar
clinical feature and pathologic process in which type I hypersensitivity
plays a key role. Vernal keratoconjunctivitis (VKC) and atopic
keratoconjunctivitis (AKC) are more severe than SAC/PAC and can
ultimately lead to vision loss. In contrast to SAC/PAC, type IV
hypersensitivity is the major mechanism of VKC/AKC.
Increasing evidence shows that the microbiome of skin, gut, and airways
play an important role in allergic diseases like atopic dermatitis, food
allergies, and asthma.3,4 For instance,Staphylococcus aureus exacerbates atopic dermatitis by inducing
skin inflammation and weakening the skin barrier.5Colonization of Moraxella , Streptococcus , andHaemophilus in the airways are associated with increased risk of
asthma possibly by promoting viral respiratory tract
infections.6 Similar to skin and other mucosal
surfaces, conjunctiva is colonized with a variety of
microbes.7–10 However, the association between the
conjunctival microbiome dysbiosis and ocular allergy remains unexplored.
Here we surveyed the conjunctival metagenomes of 39 patients with
various types of AC (SAC/PAC and VKC) and 48 healthy controls using
metagenomic shotgun sequencing. We characterized the microbial dysbiosis
associated with AC and identified distinct microbial signatures of VKC
and SAC/PAC. These findings offer new insight into the prevention and
treatment of ocular allergy.