Dermal macrophage

Immune cells in the skin

Dermal macrophages are a type of macrophage found in the dermis, the thick layer of living tissue below the epidermis that forms the true skin. These cells play a crucial role in the immune system, wound healing, and homeostasis of the skin.

Structure and Function

Macrophage engulfing bacteria

Dermal macrophages are derived from monocytes, a type of white blood cell that circulates in the bloodstream. When monocytes migrate into tissues, they differentiate into macrophages. In the dermis, these cells are strategically positioned to detect and respond to pathogens, debris, and damaged cells.

Dermal macrophages are equipped with a variety of pattern recognition receptors (PRRs) that allow them to identify pathogen-associated molecular patterns (PAMPs) on microbes. This recognition is crucial for initiating an immune response.

Role in Immune Response

Diagram of PAMPs and PRRs

Dermal macrophages are key players in the innate immune system. They act as antigen-presenting cells, processing and presenting antigens to T cells, thus bridging the innate and adaptive immune responses.

Upon encountering a pathogen, dermal macrophages can release cytokines and chemokines that recruit other immune cells to the site of infection, amplifying the immune response.

Involvement in Wound Healing

Stages of tissue repair

Dermal macrophages are essential for the wound healing process. They clear dead cells and debris from the wound site, a process known as phagocytosis. They also secrete growth factors that promote the proliferation and migration of fibroblasts and keratinocytes, which are crucial for tissue repair and regeneration.

Role in Skin Diseases

Psoriasis on the elbow

Dermal macrophages are implicated in various skin diseases. In psoriasis, for example, they contribute to the chronic inflammatory environment by producing pro-inflammatory cytokines. Similarly, in basal cell carcinoma, macrophages can influence tumor progression and the immune response to cancer cells.

Related Pages

• Macrophage
• Immune system
• Wound healing
• Skin disease
• Psoriasis
• Basal cell carcinoma