ABSTRACT
As discussed in other chapters of this book, wheezing not related to atopy is the most frequent condition associated with recurrent airway obstruction during infancy and early childhood. However, in spite of its public health impact, little was known until recently about the immune factors associated with this form of wheezing. With the advent of flexible fiberoptic bronchoscopy and modern technologies for the study of immune responses by white blood cells, new insights about the possible immunologic factors involved in wheezing not related to atopy have emerged. In epidemiologic studies, the two presentations of wheezing not related to atopy in early life, transient early wheezing and non-atopic wheezing, can be distinguished from the point of view of their risk factors and prognosis (see Chapter 1), and it is possible and likely that different immune mechanisms may be involved in their pathogenesis. Unfortunately, most available studies of wheezing among preschoolers were either retrospective or cross-sectional in design, and this precluded precise distinctions between transient early wheezing and non-atopic wheezing. In this section, published information regarding the potential immune mechanisms involved in either or both these two forms, as opposed to those presumably involved in atopic wheezing, will be reviewed. The immune mechanisms that determine immune responses to respiratory syncytial virus (RSV) during acute lower respiratory illness (LRI) are discussed separately (see Chapter 2).
