Laboratory aspects of immune deficiency in children.

The pediatrician confronted with a patient who may have a host defense abnormality often has at his disposal the tools to properly evaluate such an individual. Utilizing the simple screening tests listed in Table 3, all of the major arms of the immune system can be evaluated. If the history is not a strong one for immune deficiency and the screening tests are normal, then a thorough explanation of the normal patient with recurrent infections should be made and the patient simply observed for the development of more severe problems. Abnormal screening evaluations, or a suggestive history, usually indicates the need for referral to an immunologic center where more complicated tests of immune function can be made. Although curative therapy has not been developed for most immune deficiency diseases, definition of the patient's specific defect with appropriate laboratory tests leads to more informed genetic counselling, more appropriate therapy, and a better overall prognosis. Furthermore, only through the collection and study of such patients will successful therapeutic regimens be developed for severe immune deficiency disease.