The Impact of Epstein Bar Virus On Hodgkin Lymphoma's Histopathological Patterns in Morocco

In Morocco, improvement of living conditions and access to healthcare has increased life expectancy from 58 years in 1980 to 72 years in 2010. There has been a corresponding decrease in early childhood infections, including Epstein Barr virus (EBV) infection, which is associated with Hodgkin lymphoma (HL). Mixed cellularity (MC) was the most common histopathological subset of HL in Morocco. Prior studies have shown the shift to nodular sclerosis (NS) subset since 1998. Currently, the incidence of NS subtype is still predominant in our country.

Our aim is to study the incidence of EBV infection in HL Moroccan population and correlate its decrease to explain the shift of HL histopathological pattern.

We compared children and adults with HL diagnosed during 3 periods: 1980–1995, 1998–2005 and 2010–2011 in the same university medical centre. All histological samples were prepared for examination by paraffin method, than stained by Hematoxylin staining protocol. Immunuhistochemical features of Hodgkin Reed Sternberg cells were performed to assess the expression of antibodies markers (CD30, CD15). The EBV profiling was identified by immunohistochemical stains for EBV latent membrane protein 1 (LMP-1) for the last periods. Statistical comparison of all the features was performed by Epi Info software.

The features of 1200 HL patients were enrolled. The average number of HL cases per year was 46 patients for the first period versus 74 patients for the last period. The mean age was respectively 24 years (range 2–64 years) for the first period, 32 years (range 2–60 years) for the second period and 34 years (range 3–76 years) for the third one. Sex-Ratio showed male predominance. The comparison of HL incidence through the age over the past 30 years is further characterized by a significant higher incidence in elderly patients (2% versus 10%), and lower incidence in young children (32% versus 7%). The expression of LMP1 in HRS is significantly reduced between the two last periods (P=0.001). LMP1 positivity is higher in patients under fifteen years than in young adults. Currently, NS is the most prevalent histological subtype with a significant increasing frequency through the three periods (p< 0.001) instead of MC subtype. (Table1).

HL pattern in Morocco tends to be like in developed countries. The shift of HL histological subtype from CM to NS could be explained by the decrease of EBV infection in Hodgkin Reed Sternberg cells. More patients need to be enrolled to confirm this hypothesis

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No relevant conflicts of interest to declare.