What is your approach to checking IgG levels post vaccination to detect common variable immunodeficiency in patients with systemic lupus?

I recommend that this type of workup for primary immunodeficiency disorders be done as soon as a diagnosis of systemic lupus erythematosus (SLE) is made. In other words, order quantitative immunoglobulins (IgA, IgM, IgG) plus IgG subclasses during your initial workup.

Reasons being:

• Some primary immu...