Prognostic Significance of CD169+ Lymph Node Sinus Macrophages in Patients with Malignant Melanoma

Area of Science:

• Immunology
• Oncology
• Cell Biology

Background:

• CD169 (sialoadhesin) is a sialic acid receptor expressed on macrophages.
• Animal studies suggest CD169(+) macrophages in lymph nodes possess anti-cancer properties.
• The role of CD169(+) macrophages in human malignant melanoma prognosis is not well understood.

Purpose of the Study:

• To investigate CD169 expression in regional lymph nodes (RLN) of malignant melanoma patients.
• To determine the association between CD169 expression density and patient survival.
• To explore the relationship between CD169(+) macrophages and antitumor immunity.

Main Methods:

• Analysis of tissue samples from 93 malignant melanoma patients.
• Quantification of CD169(+) cell density in regional lymph nodes.
• Multivariate analysis to assess prognostic significance and correlation with CD8(+) T cells.
• In vitro stimulation of CD169 expression with IFNα.

Main Results:

• Higher densities of CD169(+) cells in RLNs were significantly associated with longer overall survival (P = 0.001).
• CD169(+) cell density was an independent prognostic factor.
• Increased CD169(+) density correlated with higher CD8(+) cytotoxic T cell density.
• IFNα stimulated CD169 expression in vitro; IFNα-producing macrophages and CD303(+) dendritic cells were found near CD169(+) macrophages in RLNs.

Conclusions:

• IFNα-stimulated CD169(+) macrophages in RLNs are involved in T-cell-mediated antitumor immunity.
• CD169(+) macrophage density is a significant independent prognostic factor in malignant melanoma.
• CD169 expression may serve as a valuable marker for prognosis and monitoring antitumor immunity in melanoma patients.