Common Variable Immunodeficiency
| Etiology |
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- Common Variable Immunodeficiency (CVID) is probably a heterogeneous group of disorders due to distinct molecular defects. The common etiological theme is some type of block in late stage B-cell Development leading to an absence of Plasma Cells and thus hypogammaglobulinemia which may affect all or specific antibody isotypes. Thus, although although diverse classes of isotype-switched B-cells exist in the periphery, they cannot properly differentiate into antibody-secreting Plasma Cells. Given the similar etiologies and frequent familial clustering, Isolated IgA Deficiency may be a subtype of CVID.
| Clinical Consequences |
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- Disease manifests as an infection susceptibility matching the pattern of X-linked Agammaglobulinemia of Bruton. Thus causative organisms are largely Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae and infections generally center around the sinopulmonary tract and include sinusitis, otitis media, URIs, pneumonia, pharyngitis, and bronchitis which can lead to bronchiectasis. Viral gastritis is also common and thus patients display recurrent infectious diarrhea.