Viral response to chemotherapy in endemic burkitt lymphoma.
OBJECTIVE
Some EBV-directed therapies are predicted to be effective only when lytic viral replication occurs. We studied whether cyclophosphamide chemotherapy induces EBV to switch from latent to lytic phases of infection in a series of EBV-associated Burkitt lymphomas.


METHODS
Children with first presentation of an expanding, solid maxillary or mandibular mass consistent with Burkitt lymphoma underwent fine-needle aspiration just prior to the initiation of cyclophosphamide therapy and again 1 to 5 days later. Aspirated cells were examined for latent and lytic EBV infection using in situ hybridization to EBV-encoded RNA (EBER), immunohistochemical analysis of the lytic EBV proteins BZLF1 and BMRF1, reverse transcription PCR targeting BZLF1 transcripts, and EBV viral load measurement by quantitative PCR.


RESULTS
Among 21 lymphomas expressing EBER prior to chemotherapy, 9 of 10 still expressed EBER on day 1 after therapy whereas only 2 of 11 (18%) specimens still expressed EBER at days 3 to 5, implying that chemotherapy was fairly effective at eliminating latently infected cells. Neither of the lytic products, BZLF1 or BMRF1, were significantly upregulated at the posttherapy time points examined. However, EBV genomic copy number increased in 5 of 10 samples 1 day after treatment began, suggesting that viral replication occurs within the first 24 hours.


CONCLUSIONS
Cyclophosphamide may induce the lytic phase of EBV infection and is fairly effective in diminishing EBER-expressing tumor cells within 5 days. These findings provide the rationale for a trial testing synergistic tumor cell killing using cyclophosphamide with a drug like ganciclovir targeting lytically infected cells.
Departments of Pathology and Laboratory Medicine, Otolaryngology/Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7525, USA.
Weihua
W
Tang
Paula
P
Harmon
Margaret L
ML
Gulley
Charles
C
Mwansambo
Peter N
PN
Kazembe
Francis
F
Martinson
Clifford
C
Wokocha
Shannon C
SC
Kenney
Irving
I
Hoffman
Carlie
C
Sigel
Susan
S
Maygarden
Mariah
M
Hoffman
Carol
C
Shores
D000293:Adolescent; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use; D002051:Burkitt Lymphoma / Q000188:drug therapy* / Q000453:epidemiology / Q000209:etiology / Q000821:virology*; D002648:Child; D002675:Child, Preschool; D003520:Cyclophosphamide / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D004279:DNA, Viral / Q000032:analysis; D019353:Endemic Diseases; D020031:Epstein-Barr Virus Infections / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology / Q000821:virology; D005260:Female; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D004854:Herpesvirus 4, Human / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology*; D006801:Humans; D008297:Male; D019562:Viral Load / Q000187:drug effects; D014775:Virus Activation / Q000187:drug effects / Q000235:genetics; D017735:Virus Latency / Q000187:drug effects / Q000235:genetics
D000970:Antineoplastic Agents; D004279:DNA, Viral; D003520:Cyclophosphamide