Which of the following statements is true regarding common variable immunodeficiency (CVID)?

Common variable immunodeficiency (CVID) typically presents after childhood, often between the ages of 15 to 35. This age range is significant because many cases are diagnosed in adolescence or early adulthood, highlighting that CVID can manifest later in life rather than being limited to early childhood or infancy.

In CVID, patients often experience recurrent infections due to the inability to produce adequate immunoglobulins, specifically IgG, IgA, and sometimes IgM. Moreover, while B cell quantities can be variable, it is common for individuals to have normal or low B cell quantities, but the hallmark is the dysfunctional antibody response, rather than a consistently low B cell count.

The other options do not accurately describe the typical presentation or laboratory findings associated with CVID. For instance, the condition does not exclusively present before age 5, as it can often be diagnosed later in life. Additionally, high IgM with normal IgA levels is not characteristic of CVID; in fact, patients typically have low levels of all immunoglobulins, including IgM, in many cases. Thus, the statement that CVID usually presents between ages 15 to 35 is the most accurate representation of this immunodeficiency.