Objective To study the possible mechanism of allergic reactions of Reduning Injection. Methods An embedded nested case-control study was conducted. Totally 3 000 patients with infectious diseases used Reduning Injection were monitored. The allergic patients were matched at a ratio of 1 to 4 by taking gender

age ± 5 years

medication season and drug batch as the matching factors. Four healthy volunteers were selected. The levels of immunoglobulin A（IgA）

immunoglobulin G（IgG）

complement 3（C3）

complement 4（C4）

interleukin-2（ IL-2）

interleukin-4（IL-4）

interleukin-6（IL-6）

interleukin-10（IL-10）

interferon-g（IFN-γ） and total immunoglobulin E（TIgE） were detected. Results There were 2 allergic patients. Fourteen serum samples were detected according to the matching principle. The level of TIgE in 2 allergic patients was significantly higher than the normal. The levels of IL-10 and IL-4 in 2 allergic patients were increased. The levels of IgA

IgG

C3

C4

IL-2 and IFN-γ were within the normal

with no significant difference between the healthy volunteers and matched patients. The results showed that the immune response system was activated in the patients. Conclusion The allergic reactions of Reduning Injection may be IgE-mediated typeⅠallergic reactions.