Human basophil degranulation in dermatophagoides allergies: 93 cases.

In tests conducted on 93 subjects human basophil degranulation (HBD) with Dermatophagoides pteronyssinus (DP) and Dermatophagoïdes farinae (DF), often involved in house dust allergy, were studied. The human basophil degranulation technique involves the enrichment of the circulating basophils of the patient allowing readings in the microscope on a fixed and colored slide and a count of at least 100 basophils, the minimum number necessary to give an adequate interpretation of the results. For each allergen dilution ratios of 100 microgram/ml, 10 microgram/ml and I microgram/ml were used. The degranulation was significant (p less than 0.001) for values higher than 35% (HBD positive). Out of 30 subjects with a positive skin test with DP, 27 had a positive HBD; no HBD was obtained in subjects with negative skin test (95% of concordance). With DF, out of 30 subjects the concordance reached the level of 86.6%. Contrary to previous work conducted on grass pollen extracts, no significant correlation was found between the skin test diameter and HBD. This might be due to the variable allergenic potency of the dermatophagoïdes extracts used for the skin tests. The HBD has now been confirmed as a simple and reliable technique for studying reaginic allergies.