When a patient has CVID and is then diagnosed with metastatic lymphoma receiving ongoing chemotherapy, how do you manage the trough levels?  

Assuming the patient is already on replacement therapy, I would make sure that at trough (if on IVIG, or steady state if on SCIG), the patient has protective levels against pneumococcal polysaccharides. If not, I would increase the dose and/or shorten the interval to achieve that, and record the tot...