Production of interleukin-12 by monocytes and interferon-γ by natural killer cells in allergic patients during rush immunotherapy

Abstract

Allergen specific immunotherapy modifies the immunologic response to allergen exposure; however, the role of cells composing the innate immune system, such as monocytes and natural killer (NK) cells, in this mechanism is still unclear. To examine the effect of rush immunotherapy (RIT) on early allergen-induced cytokine production by peripheral blood mononuclear cells from treated cat- and birch-allergic patients. Twelve allergic patients received RIT, and another 4 served as controls. Blood samples were taken before the start and after 3 days, 1 week, 3 weeks, and 3 months of RIT. Allergen-induced production of interleukin-12 (IL-12) by monocytes and interferon-gamma (IFN-gamma) by NK cells was evaluated by means of flow cytometry. Before the start of RIT, allergic patients had significantly lower numbers of IL-12+ monocytes compared with healthy subjects (P = .01). The percentage of IL-12+ monocytes increased after 3 months of RIT (P = .003). In the allergic control group, the proportion of IL-12+ monocytes evaluated after 3 months was not different from baseline and was significantly lower compared with that in the RIT group (P = .005). Before treatment, the percentage of IFN-gamma+ NK cells was lower in allergic patients than in healthy subjects (P = .04). The percentage of IFN-gamma+ NK cells increased after 3 weeks (P = .03) and 3 months (P = .01) of RIT. Restoration of the cytokine imbalance by immunotherapy is not only restricted to the cells of the adaptive immune system but also concerns cells composing the innate immune system.