Immunohistochemical Study of Tumor Associated-Macrophages and Microvessel Density in Multiple Myeloma

Background: Multiple myeloma (MM) is described as an increase in malignant plasma cells in the bone marrow (BM), which is linked with end-organ damage including kidney failure, lytic bone lesion, anemia, and immunosuppression. This study evaluated the degree of tumor-associated macrophages infiltration and its diagnostic value in newly identified multiple myeloma cases.

Methods: This retrospective study included 100 patients who had multiple myeloma. Patients were classified as follow: Patients with low Tumor associated macrophages, patients with high tumor associated macrophages, cases with low grade micro vessel density and patients with high grade micro vessel density. All cases underwent to detailed history taking, Clinical assessment, bone scan and laboratory tests including Immunohistochemistry of BM biopsy samples to confirm diagnosis of abnormal plasma cells (CD138 and monoclonal light chain).

Results: There was a strong positive correlation between CD163 and CD68. There was a strong positive correlation between MVD and CD68. There was a strong positive correlation between MVD and CD163. There was decreased overall survival with increased CD 68 TAMs content with median OS (50 months) in low CD 68 TAMs vs. (16.5 months) in high CD 68 TAMs. There was decreased overall survival with increased CD163 TAMs content with median OS (49.3 months) in low CD 163 TAMs vs. (25.6 months) in high CD 163 TAMs. There was decreased overall survival with increased MVD with median OS (54.6 months) in low MVD vs. (25.6 months) in high MVD.

Conclusions: Important role of TAMs expression and MVD in the prognosis of the multiple myeloma, as the elevated TAMs expression and high grade MVD associated with poor prognosis.