Allergic implications of blood disorders in infancy and childhood.

The clinical manifestations of many of the blood disorders are wholly or partially dependent on immunoallergic reactions. A growing body of evidence permits the characterization of antigenantibody mechanisms in connection with hemolytic anemia, purpura and agranulocytosis, and more specifically for each of the blood cell elements and for the vessel wall. These reactions extend to maternal-fetal relationships producing well defined blood disorders manifest at birth or in the neonatal period.Once the effects of the hypersensitive state are set in motion during the course of a blood disorder, therapeutic measures to slow their progress are often futile. Because it is not always possible to identify the potentially allergic child in whom these circumstances will occur, it is extremely important to weigh the advantages of the use of a drug before it is administered especially when its side effects have not yet been thoroughly investigated. Important information has recently been obtained regarding the heightened susceptibility to infection in children with chronic anemia who have had splenectomy to reduce the frequency of transfusions. The hypersensitive responses in children with spleen removed may result in overwhelming and often fulminating infections necessitating rigid criteria in selecting patients of the pediatric age for this operation.