Chronic Lymphocytic Leukemia |
* III. Department of Medicine,
° Institute of Virology
# Institute for Pathology, Technical University of Munich, Munich, Germany
Correspondence: Katharina S. Götze, MD, III. Department of Medicine, Technical University of Munich, Ismaningerstrasse 15, 81675 Munich, Germany. Phone: international +49.89.41406318. Fax: international +49.89.4140-4826. E-mail: k.goetze{at}lrz.tum.de
|
|
|---|
Key words: CLL, mTOR, EBV, RAD001, lymphoproliferative disorder.
Inhibition of mammalian target of rapamycin (mTOR) represents an attractive target in chronic lymphocytic leukemia (CLL).1, 2 RAD001 is a novel oral mTOR inhibitor. It is used as an immunosuppressant in solid organ transplants3 and is being developed as an anti-cancer agent.4 We report the case of a rapidly fatal EBV-associated lymphoproliferative disorder following treatment with RAD001 within a phase II clinical trial. A 70-year old woman with B-CLL was previously treated with chlorambucil/prednisone, cyclophosphamide/doxorubicin/vincristine and splenectomy for autoimmune hemolytic anemia. The patient had no other relevant medical conditions or medication. Treatment with RAD001 (5 mg daily) was begun at a white blood cell (WBC) count of 150,000/µL. WBC levels initially dropped to 100,000/µL and then stabilized (Figure 1A). The study medication was well tolerated with no side effects. After 24 weeks, leukocyte counts rose consistently and RAD001 was discontinued at a WBC count of 200,000/µL after 32 weeks. The patient was subsequently treated with one course of fludarabine/cyclophosphamide administered four days after discontinuation of RAD001, and WBC counts immediately dropped. Three weeks later the patient presented to the emergency unit with a temperature of 39°C and fatigue. Tests showed elevated serum C-reactive protein and a chest X-ray confirmed interstitial pulmonary infiltrates. The patient was admitted into hospital, i.v. antibiotics were administered and antiviral pro-phylaxis with valciclovir continued. Two days later, a new chest x-ray revealed increasing pulmonary infiltrates. EBV-DNA was detected in the bronchoalveolar fluid and at extremely high levels in plasma and peripheral blood lymphocytes (Figure 1B and C). Despite broadened antiviral and antifungal therapy, patient died of multi-organ failure. At autopsy, the lungs revealed extensive infiltrates with widespread necrosis. Histologically, the lungs, liver, bone marrow, kidney and lymph nodes showed infiltrates of small lymphocytes consistent with B-CLL. A polymorphous large cell infiltrate with Reed-Sternberg-like giant cells and necrosis was identified in the lungs and in other organs (Figure 2A). EBV-DNA was detected by PCR in these tissues (Figure 1C) and in-situ hybridization revealed abundant expression of Epstein-Barr-virus encoded early RNAs (Figure 2B). The large cells showed expression of CD20, CD30, and latent membrane protein-1 of EBV (Figure 2C-D). PCR from the splenectomy specimen and lung tissues with EBV-positive large cell proliferation showed an identical monoclonal B-cell rearrangement in both specimens, representing the B-CLL clone. Two additional clonal bands were identified in the lung, indicative of a second monoclonal B-cell proliferation (not shown).
![]() View larger version (11K): [in a new window] [Download PPT slide] |
Figure 1. Range of WBC levels and EBV viral load during the course of the patients illness. (A) Peripheral blood WBC levels during the course of the patients disease. The beginning of treatment with RAD001 and the time point of chemotherapy with fludarabine and cyclophosphamide (FC) are indicated. (B) EBV-DNA load in the bronchoalveolar fluid (BAL, grey bars) and blood plasma as detected by PCR during the final phase of the patients illness. (C) EBV-DNA detected by PCR in the cellular fraction during the final phase of the disease and at autopsy. Left panel: EBV-DNA levels in peripheral blood lymphocytes (PBL); right panel: EBV-DNA detected post-mortem in lungs, lymph nodes, liver and kidneys.
|
![]() View larger version (146K): [in a new window] [Download PPT slide] |
Figure 2. Histology, immunohistochemistry and in situ hybridization of EBV-associated lymphoproliferation in lung tissues. A. The lungs show a polymorphic lymphoid infiltrate with a mixture of small and large cells, occasional Reed-Sternberg like cells and apoptotic figures. Tissue was stained with hematoxylin and eosin (H&E) and examined through a 40x/0.75 numerical objective lens using a Zeiss Axioskop 2 plus microscope fitted with a Zeiss Axiocam camera (Carl Zeiss AG, Germany). Images were acquired using AxioVision software (Carl Zeiss AG, Germany). B. In situ hybridization for Epstein-Barr early RNAs (EBERs) reveals strong nuclear staining of most cells. Note angiocentric distribution of positive cells, 100x total magnification using a 10 x /0.30 objective lens. C. Many large cells show strong expression of Epstein Barr latent membrane protein 1 (LMP-1). ABC technique, 200 x total magnification using a 20 x /0.50 objective lens. D. The neoplastic cells show strong expression of CD20. ABC technique, 400x total magnification using a 40 x /0.75 objective lens.
|
In conclusion, while mTOR inhibitors could have a promising role in cancer therapy, they should be used with caution in patients with pre-existing immune disorders such as heavily pretreated CLL.
|
|
|---|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||