Microenvironment Assessment, Disease Characteristics and Prognosis In HIV-Associated (HIV-cHL) and HIV-Negative Classical Hodgkin Lymphoma: The Influence Of Epstein Barr Virus (EBV)

Abstract

Introduction Studies of EBV positive (+) and negative (-) classical Hodgkin lymphoma (cHL) have shown the importance of the immune microenvironment in affecting Reed-Sternberg (hRS) cell survival, proliferation, and biologic behavior. For example, macrophage infiltrates may correlate with inferior disease outcome and survival and proliferation of the hRS cells depends on trophic signals from various inflammatory cells, including CD4+ T cells. The latter finding may explain why HIV-cHL patients (pts) usually present with higher circulating CD4+ T-cell counts (cCD4) compared to HIV-related non-Hodgkin lymphoma. Pathobiologically, HIV-cHL differs from HIV negative cHL (cHL) in that it is nearly always EBV+, has higher numbers of hRS cells, presents with more advanced median stage, exhibits more commonly the mixed cellularity (MC) pattern, and some studies suggest it is more clinically aggressive. To investigate the microenvironment of HIV-cHL and its influence on cHL biology, we assessed the immune cell composition and clinical characteristics of HIV-cHL and compared the findings to those of EBV+ and EBV- cHLs. Methods 31 HIV-cHL and 40 cHL (8 EBV+/32 EBV-) cases were identified and corresponding tissue microarrays (TMAs) created. TMAs were evaluated for EBV (EBER), CD30, and microenvironment-associated antigens: PAX5, CD3, CD4, CD8, CD68, CD163 (% positive), TIA1, FOXP3 (relative number 0-4+); the hRS-macrophage microenvironment was evaluated by assessing the number of hRS where >50% of the circumference of the neoplastic cell was associated with CD68+ cells. Results were compared based on HIV status, EBV status (in HIV negative pts), demographics, cCD4 and histology; each was correlated with overall survival. Analyses were performed using non-parametric Fisher's exact test, Kaplan-Meier method and Cox Proportional Hazards model. Results M:F ratio was 9:1 in the HIV group vs. 1.3:1 in the HIV negative pts (p <0.001). The median cCD4 in the HIV+ pts at HIV-cHL diagnosis was 248 cells/mm3. No differences in age, stage, B symptoms, bulky disease, IPS score, and hRS concentration were found between HIV+ and HIV negative cHLs pts. 7% of cHLs and 33% of HIV-cHLs were classified as MC (p<0.01). 90% of HIV-cHLs were EBV+ compared to 20% of the cHL cases. Statistically significant differences were seen in the number of CD4+ and CD8+ cells between the EBV+ and EBV- cHLs irrespective of HIV status. The only difference among all the immune microenvironment markers observed between EBV+ HIV-cHL and EBV+ cHL cases was that of peri-hRS CD68 cells, which were more abundant in the EBV+ HIV-cHL (Table 1; 51% vs. 30% p<0.005). Similar differences in peri-hRS CD68 staining were observed between the HIV-cHL and all cHL pts. The only deaths in HIV-cHL pts occurred when CD68 was >15% (p<0.05). No statistical differences were noted for OS with respect to cCD4, histologic subtype, race, gender, or HIV status. Conclusions No significant differences were observed between HIV-cHL and cHL pts with respect to stage, B symptoms, bulky disease, IPS score, or overall survival, but there were more MC cases in the HIV-cHL cohort. The microenvironment of HIV-cHL and EBV+ cHL is similar, but different from EBV- cHL with respect to percentages of CD163+, PAX5+, CD4+ and CD8+ cells. The location of CD68+ macrophages was the only discordant result between the EBV+ HIV-cHL and EBV+ cHL cohorts. The differences in location of the CD68+ cells, which may be dependent on HIV status, suggests greater influence of these cells on the biologic behavior of the neoplastic process, correlating with poor survival. However, the similarity in the microenvironments in HIV-cHL and EBV+ cHL with respect to CD4, CD8, and CD163 staining implies an important role for EBV on disease biology, as well. Thus, these data suggest that EBV as well as HIV, play prominent roles in determining the immune response and disease behavior in HIV-cHL, warranting further study Disclosures: No relevant conflicts of interest to declare.