Also, κ/λ ratio could be important in the follow-up of CVID patients, and hence an altered κ/λ ratio or a sudden increase in sFLC values may be an indicator for further investigation (blood smear, LDH, serum β2-microglobulin, PET-TAC, etc.)that allows appropriate and timely strategies. This evidence concerns the gene HLA-G and common variable immunodeficiency.