What would happen to the commensal relationship between the

What would happen to the commensal relationship between the gut and gut microbiome if there was a defect in mucosal immunity, and IgA levels dropped?

Microbes would penetrate the gut and induce immunological tolerance

Nothing, because microbes would overgrow in the gut and die as IgA levels dropped

Nothing, because other arms of the immune response would compensate

Microbes would penetrate the gut and trigger chronic inflammatory responses

If IgA levels drop in gut the individual becomes immune compromised and microbes would penetrate gut and trigger chronic inflammatory responses.