Cell talk: a phenomenon observed in the keloid scar by immunohistochemical study.

Keloid is a common complication of the wound healing process. Scarce histologic studies describing changes in keloid growth or progression, regarding detailed descriptions of cellular distribution, relationship, or interaction are available. This study aimed to describe the nature, types, and interactions of immune cells (lymphocytes, macrophages, and mast cells), which predominate in keloid complications and may play a role in fibroblastic activation. In this study, 44 samples of keloid were collected, processed, and examined using both light (including routine and immunocytochemical staining) and scanning electron microscopy (SEM). This histologic study showed the characteristic disposition of abnormally thick collagen bundles and newly formed blood vessels in the keloid tissue. The latter showed endothelial hypertrophy, thickened walls with the disposition of homogenous substances, and fibrillar collagen in the perivascular tissue. Numerous mast cells were also observed. Marked cellular infiltration in the perivascular regions and among abnormal collagen was observed. Immunohistochemistry showed the dominance of (CD3) T lymphocytes together with the macrophages (CD68). Among the interesting findings that this study focused on was the cellular interaction. The contact was noticed between the fibroblast and mast cell, the fibroblast and T lymphocyte, the macrophage and both fibroblast and lymphocyte. This cell-cell interaction or contact may explain what was called in literature "cell talk" via cytokines secreted by these cells or through direct gap junctions. In conclusion, cell talk is a phenomenon that was noticed in many pathologic lesions and could explain the mechanism by which different cytokines are secreted by different cells to initiate disease or promote healing.