HLA in asthma.

100 adult patients with asthma were typed for HLA. These patients were skin tested with a panel of allergens and divided into skin test positive (61) and skin test negative (39) patients. There was a decreased frequency of HLA-B12 in the negative skin test group (18%) compared to the skin test positive group (43%) and the controls (36%). A further subdivision of these patients into extrinsic asthma (positive skin tests and/or allergic history) and intrinsic asthma (negative skin tests and no allergic history) was made. There was an increased frequency in the extrinsic asthmatics of HLA-B8 (37 compared to 28% in normals) and a decreased frequency of B12 in the intrinsic asthmatics (13 compared to 36% in normals). 4 or 5 patients who had negative skin tests but gave a history of asthma following exposure to specific allergens, suggesting a type III immune complex asthma, were both A1 and B8.