- Refractoriness to steroids will be defined based on the following criteria: (1) Performed already at least two attempts of treatment with prednisone at at least 0.5 mg/kg for 21 days in the previous 6 months and (2) treated with at least another immunosuppressive medication for 30 days in the previous 6 months and (3) Requiring at least 0.2 mg/kg prednisone for maintaining stable disease or worsening despite 0.2 mg/kg prednisone.