[1280] Human Herpes Virus 8 Viral Load in Multicentric Castleman's Disease

J Arce, C Huang, M Levin, Q Pan, H Ratech. Montefiore Med Ctr/Albert Einstein Coll Med, Bronx

Background: Multicentric Castleman's disease (MCD) is frequently associated with human herpes virus 8 (HHV8), especially in patients co-infected with human immunodeficiency virus (HIV). On the other hand, some individuals with MCD do not have detectable HHV8. To our knowledge, this is the first study to use a quantitative polymerase chain reaction (Q-PCR) assay in order to identify HHV8 in lymph nodes.
Design: HHV8 viral load (VL) was measured in lymph node biopsies from 46 HIV+ patients and 101 HIV- individuals using a Q-PCR assay originally developed for plasma (J Clin Microbiol 39:4269, 2001). We normalized HHV8 VL values to a mammalian house-keeping gene, HCK. For HHV8-positive controls, we tested Kaposi sarcoma (KS) in skin (N=5) and primary effusion lymphoma (PEL; N=1). In addition, we immunohistochemically stained lymph node tissue sections for HHV8 latent nuclear antigen (LNA-1).
Results: The lower limit for sensitivity of the HHV8 Q-PCR assay was 70 viral copies per reaction. The HHV8 VL data is expressed as viral copy number per cell. Among the HHV8-positive control samples, the VL for KS in skin ranged from 5.3E+01 to 6.9E+02. A single case of PEL had the highest VL equal to 1.2E+04. HHV8 was detected by Q-PCR in 10/147 lymph nodes: 4.4E+02 ± 6.4E+02 (mean ± sd); range, 0.5E+00 to 2.1E+03. Q-PCR HHV8 and immunostaining results for LNA-1 agreed, except in patient no. 10, who did not have MCD (Table 1). All LNA-1-positive lymph nodes had an HHV8 VL of at least 2.6E+01. The HHV8 VL in lymph nodes was not influenced by the presence of KS in another anatomic site or by highly active antiretroviral therapy (HAART).

HHV8 viral load in lymph nodes
+, positive; -, negative; KS, Kaposi sarcoma; LN, lymph node.

Conclusions: The HHV8 VL for KS in skin and MCD in lymph nodes was similar. In 1/10 lymph nodes, HHV8 could be detected by Q-PCR but not by immunostaining. Low HHV8 VL in lymph nodes could represent either a preclinical stage of MCD or evidence of a latent HHV8 infection. There still remain a minority of MCD patients without detectable HHV8.
Category: Hematopathology

Monday, March 22, 2010 1:00 PM

Poster Session II # 142, Monday Afternoon


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