Immunodeficiency diseases

ALTHOUGH more than 50 genetically determined immunodeficiency syndromes have been reported since 1952,1defects in immunity were considered rare until the acquired immunodeficiency syndrome (AIDS) emerged over 10 years ago.2This growing list of diseases now encompasses all major components of the immune system, including lymphocytes, phagocytic cells, and complement proteins.1,3-5 EVALUATION OF THE PATIENT WITH RECURRENT INFECTIONS It is essential that the clinical and laboratory tests selected for immunologic assessment be broadly informative, reliable, and cost-effective. Most of these disorders can be ruled out at little cost to the patient if the proper choice of screening tests is made (Table 2-1). A complete blood cell count and erythrocyte sedimentation rate are among the most cost-effective screening tests. If the erythrocyte sedimentation rate is normal, chronic bacterial infection is unlikely. If the absolute neutrophil count is normal, congenital and acquired neutropenias and severe chemotactic defects are eliminated.