Which of the following syndromes would you expect to see recurrent infections due to deficient antibody production?

In the context of recurrent infections due to deficient antibody production, Hyper-IgM syndrome is indeed the most relevant condition. This syndrome is characterized by an inability to class switch from IgM to other antibody isotypes, such as IgG, IgA, and IgE. As a result, individuals with Hyper-IgM syndrome typically have high levels of IgM and significantly low levels of other immunoglobulin classes. This deficiency in producing adequate antibodies leads to an increased susceptibility to infections, particularly with encapsulated bacteria and certain viruses.

Understanding why this syndrome leads to recurrent infections is crucial. Due to the lack of diverse antibody types, the immune system struggles to mount effective responses to a wide variety of pathogens. Antibodies play vital roles in neutralizing pathogens and marking them for destruction by other immune cells, and without proper antibody production, this process is severely hindered.

DiGeorge syndrome, while involving immunological defects, is primarily characterized by the absence or underdevelopment of the thymus, leading to T-cell deficiencies rather than direct antibody production issues. Wiskott-Aldrich syndrome involves eczema, thrombocytopenia, and a compromise in both humoral and cell-mediated immunity, but it does not solely focus on antibody deficiency. Severe Combined