ALLERGEN-INDUCED MIGRATION OF HUMAN-CELLS IN ALLERGIC SEVERE COMBINEDIMMUNODEFICIENCY MICE

Recently, we have shown that severe combined immunodeficiency (SCID) m ice, intraperitoneally reconstituted with peripheral blood mononuclear cells (PBMC) from Dermatophagoides pteronyssinus (Dpt)sensitive patie nts, produced human IgE and developed a pulmonary inflammatory-type re action after exposure to allergen aerosol. Tn order to understand the potential mechanisms involved in the human cell migration in SCID mice , we analysed their phenotypic profile in the lungs, spleen and thymus , 2 months after Dpt inhalation. The human cell recruitment in these o rgans was found to be allergen-dependent as CD45(+) human cells were o nly detected in hu-SCID mice after Dpt exposure. The composition of th e pulmonary human T-cell infiltrate, preferentially memory (CD45RO), a ctivated (human leucocyte antigen (HLA)-DR) and CD4(+) cells, was simi lar to that described in asthmatic patients. However, CD20(+) B cells were predominately recruited in the spleen and thymus and may be IgE-p roducing cells in the spleen. In the lungs, the percentage of human le ucocytes expressing the alpha-chain of the lymphocyte function-assicia ted antigen-1 (LFA-1) (CD11a) was higher than those of CD49d(+) or CD5 4(+) cells, in contrast to the spleen and thymus, suggesting a potenti al role of LFA-1 in the human cell migration towards SCID mice lung. T n conclusion, this model could be useful in the study of factors impli cated in the cellular migration towards the lymphoid organs during an allergic reaction.