Selective IgA deficiency is a condition of an individual's immune system where they do not have enough of an antibody or protein with the function of fighting infections called immunoglobulin A (IgA). Selective IgA deficiency is characterized by indiscernible levels of immunoglobulin A in a patient's secretions and blood. Individuals affected by this deficiency do not typically have a deficiency of any other immunoglobulin proteins. Different immunoglobulin proteins are present in different defense mechanisms in a patient's body.
Most of an individual's immunoglobulin A is present in the mucosal surface secretions such as colostrum, respiratory secretions, saliva, gastrointestinal secretions, tears, and genital secretions. These body regions in healthy individuals are well protected from pathogens because of immunoglobulin A presence. An estimated one out of every five hundred Caucasians is affected by selective IgA deficiency. Half of the affected individuals experience symptoms related to increased infection susceptibility.
Frequent and recurrent ear infections can be a symptom manifestation in an individual affected by selective IgA deficiency. The most common type of ear infection in affected individuals is one of the middle ears called acute otitis media. Bacteria and viruses can enter and colonize an individual's middle ear space through the Eustachian tube and nasopharynx. The most common viruses responsible for the recurrent ear infections in selective IgA deficiency patients include adenovirus, respiratory syncytial virus, rhinovirus, and bocavirus.
The types of bacteria that most commonly cause selective IgA deficiency precipitated ear infections are Hemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis. The presence of immunoglobulin A in a patient's upper respiratory tract and inner ear lining of epithelial cells is imperative to prevent the growth and spread of viruses and bacteria that cause ear infections. Recurrent ear infections because of this immune deficiency can cause an affected individual to experience hearing loss.