[1247] Plasmacytoid Dendritic Cells in Lymph Nodes of Patients with HIV.

Brijal Dave, Jennifer Kaplan, Parul Bhargava. Beth Israel Deaconess Medical Center, Boston, MA

Background: Plasmacytoid dendritic cells (PDC) are major type I interferon producing cells. Blood PDC counts decrease in human immunodeficiency virus (HIV) infected patients; this correlates with a fall in CD4 T-cell counts & inversely with viral load. Lymph node (LN) PDC evaluations have shown variable results in Simian Immunodeficiency Virus infected macaques; while one study suggested an accumulation of PDC in lymph nodes (LN), another showed a parallel loss of PDC in LN & blood. To date, no study has evaluated PDC by immunohistochemistry (IHC) in LN of humans infected with HIV. In this retrospective study, we studied PDC in LN from HIV infected patients, using CD123 IHC. We propose to establish a relationship between PDC counts in LN with CD4 counts & antiviral therapy.
Design: CD123 IHC was performed on 29 LN biopsies from 26 HIV patients. These included 20 reactive, 4 Hodgkin lymphoma (HL), 3 non-Hodgkin lymphoma (NHL), 1 metastatic lung carcinoma & 1 necrotic LN. CD4 counts & duration of antiviral therapy was retrieved from clinical charts. 12/18 reactive cases were on anti-retroviral therapy (data not available in 2). CD123 IHC slides were blindly reviewed for number of PDCs/10 high power fields, intensity, pattern of staining & degree of clustering. The latter was scored on a scale of 1-4 as follows: 1: no clusters 2: rare small clusters 3: medium sized, loose clusters 4: large tight clusters. Correlation of PDC with CD4 counts & antiviral therapy was evaluated.
Results: PDC were interfollicular, with loose to tight, mostly perivascular clustering. PDC had moderate to strong cytoplasmic granular staining, with membranous accentuation. Although no correlation between PDC number & CD4 counts was noted, increased clustering of PDC with lower CD4 counts was observed.

Larger clusters (scores 3, 4) were exclusively seen in untreated patients. Although number of lymphoma cases was limited, NHL had lower PDC counts than HL.
Conclusions: To our knowledge, this is the first study describing IHC evaluation of LN PDC in patients with HIV. We demonstrated increased clustering of PDC with lower blood CD4 counts, & in untreated patients. This supports the hypothesis that PDC migrate to LN in HIV, similar to that described in other infections, & may contribute to blood PDC depletion.
Category: Hematopathology

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 149, Tuesday Afternoon

 

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