How would you approach a patient with SLE and class II LN who has persistent lupus activity and incomplete B-cell depletion on rituximab therapy?  

Great question! I would first make sure that their nephritis has not evolved/progressed by rebiopsying the patient if it has been a while since their last biopsy and/or they have developed new signs/symptoms of kidney involvement since their last biopsy (such as increasing UPC, decreasing complement...