Tumor-infiltrating CD163-positive macrohages, clinicopathological parameters, and prognosis in classical Hodgkin lymphoma

8528 Background: Classical Hodgkin lymphoma (cHL) is characterized by a minority of neoplastic cells surrounded by a heterogeneous background of non-neoplastic cells. A possible prognostic role of LAMs in cHL and follicular lymphomas has been suggested. CD163 is a haemoglobin scavenger receptor expressed by monocytes/macrophages. A high CD163 expression has been observed in macrophages belonging to the “alternative activation” pathway suggested to have pro-tumoral effect. The aim of the present study was to correlate the expression of the tumor-infiltrating CD163+ LAMs with clinico-pathological features and prognosis in a cohort of previously untreated HL patients (pts). Methods: A tissue microarray (TMA) was constructed with paraffin embedded tissue specimens from 286 cHL cases. CD163 expression was assessed immunohistochemically and the degree of intratumoral LAM infiltration was scored semi-quantitatively. Clinical data were obtained from the Danish population-based lymphoma registry and clinical records. All pts were homogeneously treated with either chemo-radiotherapy (localised disease) or ABVD chemotherapy (advanced disease). Results: The median age was 37 yrs (range: 6–86 yrs). The M:F ratio was 1.2. The histological subtypes were: nodular sclerosis (NS)-type I, 167 cases (59 %); NS-type II, 71 (25%); mixed cellularity (MC), 44 (15 %); lymphocyte-rich, lymphocyte-depleted and cHL-NOS, each one case. Of 253 pts with assessable International Prognostic Score (IPS), 204 had a low-risk (≤ 2) and 49 a high risk (>2) profile. A high number of tumour-infiltrating CD163+ cells was associated with a significantly poorer overall and event-free survival (p=0.029 and p=0.018, respectively). Furthermore, a high expression of CD163 strongly correlated to stage IV disease (p=0.035), presence of B-symptoms (p=0.008), lymphocytopenia (p=0.003), hypersedimentation (p=0.009). In a multivariate analysis, IPS score > 2 remained the strongest predictor. Conclusions: In cHL, a high number of intratumoral CD163+ monocytes/macrophages correlates with adverse outcome and with clinical parameters reflecting underlying aggressive disease biology. No significant financial relationships to disclose.