humoraldefekter

Humoral defekter, or defects in humoral immunity, refer to conditions in which the body's ability to produce or utilize antibodies is impaired. These disorders can be primary (congenital) or secondary (acquired) and lead to increased susceptibility to infections, especially from extracellular bacteria and certain enteric pathogens. The central feature is reduced quantity or quality of antibodies, impaired specific antibody responses, or defects in B cell development and function.

Primary humoral defects include a spectrum such as agammaglobulinemia (very low or absent immunoglobulins due to B cell development failure), common variable immunodeficiency (CVID) with low IgG and often IgA/IgM and poor vaccine responses, selective IgA deficiency, IgG subclass deficiencies, specific antibody deficiency with poor responses to vaccines despite normal Ig levels, and hyper-IgM syndrome where class switching is impaired. Secondary defects arise from conditions or treatments that suppress antibody production or loss, including protein-losing states, malnutrition, HIV infection, malignancy, and immunosuppressive therapies such as rituximab.

Clinical presentation typically includes recurrent sinopulmonary infections, otitis media, pneumonia, and gastrointestinal infections. Autoimmune or inflammatory manifestations may occur in some disorders (notably CVID). Early onset or persistent infections should prompt evaluation of humoral immunity.

Diagnosis relies on immunologic testing: quantitative immunoglobulin levels (IgG, IgA, IgM), assessment of specific antibody responses to vaccines, B cell enumeration, and, when appropriate, genetic testing. Diagnosis guides management.

Treatment focuses on preventing infections and preserving lung health. Immunoglobulin replacement therapy (IVIG or SCIG) is central for many antibody deficiencies. Antibiotic prophylaxis, vaccination planning (including avoidance of certain live vaccines in severe deficiency), and management of complications are important components, usually coordinated by immunology specialists.