[Asthma and infection: interrelations].

The frequent interaction of infection in asthma is a result of a complex interrelationship. Infectious agents are capable both of inducing asthmatic crises and, at least for viruses, of initiating the asthmatic process. They also favour a specific IgE response to allergens. Similar immunity is involved in defence against these infectious agents but this immunity can be disturbed in asthmatic subjects; as seen with defects in immunoglobulin subclasses, disturbance in T lymphocyte function, monocytes and blood neutrophils. The determination of the genetic or acquired character of these disturbances is pre-condition for the development of a therapeutic substitute.