To establish a new classification in bronchial asthma, antigen-induced immediate asthmatic response (IAR) and late asthmatic response (LAR) to mite and Candida were compared with antigen specific IgE antibody (IgE RAST) and lymphocyte blastogenesis (Ly-BL) in asthmatics. Half of asthmatics with a high score on mite IgE RAST could not be provoked to IAR, although almost all of patients with house dust-induced IAR showed a high score on mite IgE RAST. However, asthmatics with enhanced Ly-BL following exposure to mite and Candida showed highly provoked LAR by antigen inhalation, and LAR patients showed significantly enhanced Ly-BL by both antigens (p<0.01). Bronchial asthmatics were classified into the following 4 groups using those parameters ; A group (IgE RAST+, Ly-BL-), B group (IgE RAST+, Ly-BL+), C group (IgE RAST-, Ly-BL+), D group (IgE RAST-,Ly-BL-). Half of the patients with IAR belonged to the A and B groups, and almost all of the LAR patients were in the B or C group. Patients in the A group predominantly showed early onset, however patients in the B and C groups showed late onset. A and B group patients were mild or moderate asthmatics, but severe asthmatics belonged to the C and D groups. These data suggest that the C group showed only Ly-BL led LAR by "cell-mediated allergy" in late onset severe asthma.