HUMARA analysis of patients with eosinophilia. Case 1, idiopathic hypereosinophilic syndrome; case 2, Churg-Strauss syndrome; case 3, eosinophilia secondary to phenytoin ingestion; case 4, eosinophilia secondary to Strongyloidiasis infection; and case 5, eosinophilia secondary to house dustmite allergy causing atopic eczema. Case 1A, sample obtained at initial presentation; case 1B, sample obtained 26 months after initial presentation; EO, purified eosinophil fraction; WBC–, eosinophil-depleted leukocyte fraction; +, DNA amplified after HpaII precutting; –, DNA amplified without HpaII precutting; *, percent allelic ratio: this is the ratio of the band intensity of the upper allele to the lower allele after HpaII digestion as a percentage of the total intensity of the two alleles. The intensity of each band after HpaII digestion was first corrected by dividing it by the signal obtained for that allele in the undigested sample (for details, see Materials and Methods). †, eosinophilia: percentage eosinophils of the peripheral blood total white cell count before eosinophil purification.