The frequency of HLA-A, -B, and -C loci antigens in random populations of Alternaria-sensitive (N = 100) and perennial nonallergic asthmatics (N = 87) were compared with age- (+/- 5 yr) and sex-matched controls from the same geographic region. There was no association between HLA antigens as measured by frequency analyses and Alternaria-sensitive or perennial nonallergic asthma. Moreover there was no association between HLA antigens and the age of onset of asthma, associated allergic disorders, various environmental factors provoking asthma, total serum IgE levels, and Alternaria-specific IgE antibody.