Increasing evidence supports the hygiene hypothesis as a
pathogenic basis for allergy, meaning that early-life exposure to
certain allergens and bacteria might be associated with significant
reductions in AR symptom severity and atopy.5,16-18 Recently,
Palm et al5 revisited the tenets of the hygiene hypothesis. Although
allergies are generally viewed as a mistargeted immune response
that evolved to provide immunity to infectious agents, these authors
posited that allergic immunity also has an important role in host defense
against multiple noninfectious environmental insults.5Therefore
we postulated that cockroach sensitization (C1) might be a
proxy for childhood exposure to infectious and other environmental
agents. We determined whether C1 status was associated with (1)
mitigation of AR symptom severity in participants of study sets 1
and 2 in both the ACC and natural settings and (2) dampened immune
activation/responses in study set 1 participants.