IGHE and immunodeficiency disease: Repeated infections may alter immune homeostasis [22], leading to dysfunctional antibody or T-cell responses that enhance susceptibility to dengue-related vascular complications [23]. Heterotypic antibodies, such as neutralizing antibodies specific to the dengue serotype and IgE in recurrent chest infections in certain immunodeficiencies [23], may trigger an exaggerated immune response, causing vascular leakage in DHF [24].