How do you approach hypogammaglobulinemia monitoring when using obinutuzumab for refractory nonrenal SLE patients?

I would start with a baseline evaluation that includes quantitative IgG levels, HBV serologies, including HBsAg and anti-HBc, to assess reactivation risk even if HBsAg-negative, and a CBC with differential. Before treatment, I would make sure all non-live vaccines are completed, and I would avoid live vaccines during therapy and until B-cell recovery. During treatment, I would recheck Ig levels before each redosing cycle and every 3 to 6 months, along with a CBC to monitor for neutropenia, which can be late-onset and has been reported as grade 3–4 in about 7% of lupus nephritis trials. I would also monitor CD19/CD20 counts to confirm B-cell depletion and anticipate repopulation, which typically occurs around week 36 in SLE. If IgG remains p...