Characterization of macrophage innate immune response at the site of Epsein Barr Virus (EBV) entry in pediatric patients

Abstract

Macrophage?s role in the management of Epstein Barr virus (EBV) infection is unexplored. Therefore, our aim is to characterize macrophages in tonsil microenvironment in pediatric patients infected with EBV. Methods: We studied 72 patients with tonsil surgery. The infection status was studied by Anti-EBV VCA-IgM, VCA-IgG, EA-IgG and -EBNA1 IgG, to define primary infection (PI), healthy carrier (HC), reactivation (R) and no infected (NI). Viral load and typification was assessed by PCR. Latency pattern was evaluated by Immunohistochemistry (IHC) for LMP1, EBNA2 and BMRF1, and EBERS in Situ Hybridization (ISH). Macrophages characterization was performed by CD68, CD163, and CD169 IHC,in germinal center (GC) and interfollicular (IF) regions and results were expressed as positive cells/mm2.Results:Of our patients, 38 wereHC, 20 PI, 10 had viral Rand 4 were NI. 41.5% of patients expressed Latency I, 31.7% Latency II, 12.2% Latency III and 14.6% Latency 0, while 14.6% also showed positive cells for lyticantigens. We defined the macrophage´spolarization profile M1as CD68/CD163 >1.5, and M2 as CD163/CD68 >1.5;M1 profile was observed in 89% of the patients. CD68+ cell counts was statically higher compared to CD163+ and CD169+ in the entire series and within groups (ANOVA p<0.05). Both CD68and CD163 cell counts were statistically higher in the IF region in the whole series and in the 3 subgroups (PI, P and R)(p<0.05 T test), whereas CD169+ cells were statistically increased at theGC in the entire cohort, and in HC subgroup (p<0.05 T test). When latency patterns were clustered into 0-I and II-III, only a mayor recruitment of CD163+ cells in patients expressing Latency II-III was observed (Unpaired T test p=0.01). No correlation between viral load and CD68, CD163 or CD169 were demonstrated (p<0.05 Spearman)and no significant differences were evidenced these markers between EBV1 or EBV2 types (p>0.05, unpaired T test). Conclusions: This is the first work that characterize the macrophages involvement at the site of viral entrance. The prevalence of CD68 over CD163 shows a predominance of M1 profile, with antimicrobial and inflammatoryactivity, regardless of the infection status. These results are in line with previous observations in our laboratory, in which M1 prevails in the microenvironment of EBV- associated Hodgkin Lymphomas (HL). Therefore, M1 polarization pattern is prevalent in the context of EBV infection, despite the lymphomagenesis process.