Levamisole can regulate immune function, mainly acting on T lymphocytes to induce the early differentiation and maturation of T cells into functional T cells, thereby promoting the normal ht function of T cells. It can also enhance the phagocytic and chemotactic functions of macrophages to increase the activity of natural killer cells, produce endogenous interferon, and improve immune function to make it normal. Effectively prevent the progression of pneumonia and improve symptoms such as coughing and lung sounds. In addition, after the immune function of the child patient weakens, taking levamisole hydrochloride can increase the total complement content in the blood, especially the production of IgG and IgA, thereby improving the immune effect of the respiratory tract mucosa and playing a role in virus resistance and prevention of bacterial infection. Levamisole can not only regulate the immune system but also restore it. It can show bidirectional regulation for abnormal humoral immune function, making it tend to normal development and helping to restore the low cellular immune function to normal.