The Effect of Sirolimus on Immunizations During the Treatment of Kaposiform Hemangioendothelioma

Inclusion Criteria: * Case groups: * KHE patients treated with sirolimus. * After immunoglobulin and flow cytometry assays, as well as outpatient evaluation and assessment, those participants will be vaccinated with live attenuated vaccines or inactivated vaccines in a timely order according to the advice. * Control groups: * Healthy children with no immune deficiencies. * Participants are vaccinated according to the National Immunization Program in a timely manner. * Participants are matched to the case group according to age. Exclusion Criteria: * HBsAg, HBeAg positive, or other active infectious diseases; * History of immunodeficiency or low immunoglobulin levels; * Autoimmune disease or fever during blood collection; * Use of other medication or surgery; * Suffering from other bleeding disorders; * Suffering from other solid tumors or hematological tumors, etc.; * Withdraw informed consent.