Immunohistochemical Characterization of Tumor-Associated Macrophages in Canine Lymphomas

Macrophages have been confirmed to play a significant role in the behavior of human lymphomas, albeit no consistent data are so far available in canine lymphomas. The present study characterizes the macrophages present in cases of canine nodal lymphoma and their relationship with the histological grade and the immunophenotype. Samples from the lymph nodes of 25 dogs diagnosed with lymphoma were selected. Immunohistochemistry was used to determine the tumor immunophenotype (CD3 and CD20 antibodies) and macrophage characterization (Iba1, MAC387, CD204, CD163 and iNOS antibodies). Macrophage counting was performed in 10 randomly selected, high-power fields per sample. Generalized linear models with Poisson distribution were used for statistical analysis. A significantly greater number of macrophages (Iba1+) were detected in high-grade and B-cell lymphomas. The highest amount of both M1 (iNOS+) and M2 (CD204+ and CD163+) subtypes were observed in B-cell lymphomas. High-grade lymphomas showed a greater number of CD204+ and CD163+ cells and recently recruited MAC387+ macrophages. The latter were most abundant in T than in B-cell lymphomas. In conclusion, a significant population of macrophages is present in canine lymphomas, which constitute a heterogeneous population that shows variations in the amount and immunohistochemical profile according to the histological grade and immunophenotype.

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Aggressive B-cell lymphoma cases with 11q aberration patterns indicate a spectrum beyond Burkitt-like lymphoma

Blood Advances ◽

10.1182/bloodadvances.2021004635 ◽

2021 ◽

Author(s):

Niklas Gebauer ◽

Hanno M. Witte ◽

Hartmut Merz ◽

Ilske Oschlies ◽

Wolfram Klapper ◽

...

Keyword(s):

B Cell ◽

Cell Lymphoma ◽

B Cell Lymphoma ◽

Hiv Positive ◽

High Grade ◽

Lymphoma Patient ◽

B Cell Lymphomas ◽

Aggressive B Cell Lymphoma

The recent characterization of a group of non-MYC rearranged aggressive B-cell-lymphomas, resembling Burkitt lymphoma (BL), characteristically harboring a telomeric 11q-loss or combined 11q-proximal gains/loss-pattern has led to the introduction of the provisional entity of Burkitt-like lymphoma with 11q aberration (BLL-11q). Prompted by the discovery of a telomeric 11q-loss in an HIV-positive high-grade B-cell lymphoma patient, we investigated an extended cohort of aggressive B-cell-lymphomas, enriched for cases with histopathological features intermediate between DLBCL and BL including double- and triple-hit lymphomas (n = 47), for 11q-loss/combined 11q-proximal gains/loss-pattern by fluorescence-in-situ-hybridization. We provide first evidence that 11q-aberrations can be found in both BLL in the context of an underlying HIV-infection as well as in high-grade B-cell-lymphomas (HGBL) with MYC, BCL2 and/or BCL6 rearrangements. We therefore propose, that the clinicopathological spectrum of malignancies carrying this aberration may be broader than previously assumed.

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