Memory B Cells and Antibody Responses to Vaccines in Infected Children (MARVIC) With Recurrent Infections: Protocol for a Prospective Observational Study

Background

Recurrent infections are a common concern in pediatric practice and may prompt evaluation for an underlying inborn error of immunity, particularly when infections are severe, persistent, unusual, or recurrent. Recurrent sinopulmonary infections such as pneumonia, sinusitis, and otitis media may indicate a humoral immune defect, as antibody deficiencies are among the most common inborn errors of immunity. Laboratory tests typically include measurement of serum immunoglobulins (immunoglobulin G [IgG], immunoglobulin A [IgA], and immunoglobulin M [IgM]) and IgG subclasses (IgG1, IgG2, IgG3, and IgG4), assessment of vaccine-specific antibody responses, and enumeration of B-cell subsets. Together, these tests assess the quantitative and functional components of humoral immunity. However, pediatric reference intervals for these immunological parameters have not been established in Malaysia.