Successful Cyclophosphamide Desensitization in a Pediatric Patient with Systemic Lupus Erythematosus

Background: Cyclophosphamide (CYC) is an alkylating agent used to treat malignancies and autoimmune diseases. It is often given with mercaptoethane sulfonate (mesna) to prevent bladder toxicity. Hypersensitivity to CYC has been well described in adult patients with malignancy. These reactions are typically IgE-mediated to CYC or its metabolites after a previous exposure. Most of these patients have tolerated subsequent treatments by desensitization. We report the first described case of anaphylaxis after initial exposure of CYC in a pediatric patient with systemic lupus erythematosus (SLE) who successfully tolerated subsequent CYC by desensitization. 

Method: Case description

Results: An 11-year-old girl with SLE and Class III/V nephritis was admitted for hematuria, anasarca, and uncontrolled hypertension consistent with SLE nephritis flair. Her treatment was switched from mycophenolate mofetil to monthly CYC (945mg, 0.75 gm/m2) intravenously (IV) with mesna infusions given 30 minutes prior and 3, 6 and 9 hours after CYC infusion. Immediately after completing her first CYC infusion, she developed increased erythema at her IV site, angioedema of the lips and tongue, facial flushing, shortness of breath, chest tightness, and wheezing. She was treated for anaphylaxis with intramuscular epinephrine, IV diphenhydramine, methylprednisolone, and famotidine with improvement. An hour later, she became hypotensive (BP 91/31 from BP 147/69). Antihypertensives were held and she continued receiving IV diphenhydramine and methylprednisone. She received her post-treatment mesna infusions without any adverse event. She had no history of allergies or exposure to alkylating agents in the past. CYC was the preferred therapy as her renal function improved after her first treatment and Allergy was consulted to evaluate whether her anaphylaxis was secondary to mesna or CYC and for possible desensitization. Allergy evaluation revealed negative percutaneous testing to mesna (10mg/ml skin prick; 0.01mg/ml and 0.1mg/ml intradermal). CYC skin testing was deferred by the patient’s guardian. She was admitted to the intensive care unit to receive CYC via a 12-step desensitization protocol. Her daily prednisone 40 mg dose was increased to methylprednisone 1 gm at 45 minutes prior to desensitization. She was also premedicated with diphenhydramine 25 mg and famotidine 20 mg at 20 minutes prior to desensitization. She tolerated desensitization without any adverse reactions. Since then, she has received CYC by desensitization every month at an outpatient infusion setting without any adverse event.

Conclusions: Hypersensitivity to CYC can be seen in pediatric patients with autoimmune disease. It can occur after initial exposure and can be as severe as anaphylaxis. Desensitization is one approach for continued treatment with CYC in pediatric patients with SLE which has been successful.