Which condition involves poor vaccine response and sinopulmonary infections?

Hyper-IgM syndrome is characterized by a defect in class switching of immunoglobulins, which leads to a disproportionately high level of IgM but low levels of other immunoglobulin classes such as IgG and IgA. This defect occurs due to mutations affecting CD40 ligand or CD40, which are crucial for B cells to undergo class switching and produce functional antibodies.

Patients with hyper-IgM syndrome have a poor response to vaccines, especially polysaccharide vaccines, because their bodies cannot produce the necessary types of antibodies (IgG) that are typically generated in response to these vaccines. This results in an increased susceptibility to sinopulmonary infections, as they are unable to mount an adequate immune response against common pathogens that would normally be controlled by specific antibody production.

In contrast, while other options like X-linked agammaglobulinemia, common variable immunodeficiency, and selective IgA deficiency also have immune deficiencies associated with increased infections, they present with different profiles of immunoglobulin levels and vaccine responses. For example, X-linked agammaglobulinemia primarily leads to the absence of all immunoglobulin classes due to a lack of B cell development, while common variable immunodeficiency typically has reduced but detectable levels