Immediate hypersensitivity to Parthenium hysterophorus. I. Association of HLA antigens and Parthenium rhinitis.

Lymphocytes collected from rhinitis subjects with strong positive skin reactions to the pollen allergens of Parthenium hysterophorus (American feverfew) having moderate to high titres of Parthenium-specific serum IgE were analysed for association of HLA-antigens covering 13 specificities of HLA-A, 17 specificities of HLA-B and eight specificities of HLA-DR loci by the NIH two-stage microlymphocytotoxicity assay. Comparison of the phenotypic frequencies of HLA-A and B antigens between Parthenium rhinitis subjects (n = 22) and control subjects (n = 137) did not suggest any significant association when tested for these antigen specificities. A significant correlation in the association of HLA-DR3 antigen with a relative risk of 11.33, however, was observed in Parthenium rhinitis subjects (n = 30) when compared to controls (n = 50).