Final answer:
Individuals with Selective IgA deficiency have increased levels of IgM in their secretions, as their bodies attempt to compensate for the lack of secretory IgA, leaving them more susceptible to infections.
Step-by-step explanation:
People suffering from Selective IgA deficiency have increased IgM in their secretions. Individuals with this immunodeficiency condition normally produce levels of IgG and IgM but have a notable absence of secretory IgA.
Since IgA plays a critical role in defending against respiratory and digestive pathogens, the body compensates for its lack by increasing production of IgM, particularly in the dimeric form in secretions. This adaptation, however, is not entirely effective, and as a result, these individuals are more susceptible to lung and gastrointestinal infections.