The patient described in our report received four rituximab infusions in an off-label setting, followed by two additional doses over 6 months. Clinical remission was achieved for 7 months after which it was possible to interrupt steroid treatment. The pattern of immune reconstitution after rituximab therapy revealed persistently low immunoglobulin levels, partially corrected by the substitutive therapy. Immunoglobulin levels reached their normal range in 18 months and the lymphocyte subpopulations returned to normal range in 16 months. It is, nevertheless, difficult to quantify the real role of rituximab in this heavy immunosuppression, since a combined therapy with high doses of methylprednisolone and cyclophosphamide was subsequently started. Even though our patient did not present any early side effects related to the rituximab infusions, a prolonged follow-up should be carried out to monitor and prevent long-term side effects of rituximab, which are still unknown.