4.1-Inflammation

What are the dominant cells in chronic inflammation?

MACROPHAGES

What are the three key features of chronic inflammation?

Mononuclear cell infiltrate, tissue destruction, healing via angiogenesis/fibrosis

What cytokine induces classical (M1) macrophage activation?

IFN-γ

What cytokines induce alternative (M2) macrophage activation?

IL-4 and IL-13

Which macrophage type is microbicidal and pro-inflammatory?

M1 macrophage

Which macrophage type promotes tissue repair and fibrosis?

M2 macrophage

Which cells produce antibodies at sites of inflammation?

Plasma cells

What protein in eosinophils is toxic to parasites and host tissue?

Major basic protein

What antibody mediates eosinophil responses in allergies and parasitic infections?

IgE

What receptor on mast cells binds IgE?

FcεRI

What do mast cells release during immediate hypersensitivity reactions?

Histamine and prostaglandins

Which cells are the main source of IL-4 and IL-13 in allergic disease?

Basophils

Which cells are still present in some chronic infections like osteomyelitis?

Neutrophils

Name the granuloma-mediating cytokine produced by Th1 cells.

IFN-γ

List three infectious causes of granulomatous inflammation.

Mycobacteria, fungi, parasites

What are the main features of rheumatoid arthritis?

Immune-mediated chronic synovial inflammation, joint destruction, rheumatoid nodules

What environmental exposures can cause chronic inflammation?

Silica dust, coal dust, lipids

What are the histological features of chronic inflammation in the liver?

Lymphocytes, plasma cells, monocytes/macrophages (no neutrophils)

What signals are necessary for resolution of acute inflammation?

Curtail leukocyte influx, macrophages phagocytose apoptotic neutrophils, fibroblast phenotype reversion

What term describes monocyte-derived tissue phagocytes like Kupffer cells and alveolar macrophages?

Mononuclear phagocyte system

What triggers delayed-type hypersensitivity?

Persistent infections (e.g., mycobacteria, fungi)

Which mediator is responsible for activating macrophages in granulomatous inflammation?

Interferon-gamma (IFN-γ)

What are common immune-mediated causes of chronic inflammation?

Lupus, rheumatoid arthritis, chronic thyroiditis, primary biliary cirrhosis

What is a hallmark of the late stage of chronic hypersensitivity diseases?

Fibrosis

What is the duration of acute inflammation?

Short (days)

What is the duration of chronic inflammation?

Long (weeks to years)

What are two key cytokines that mediate resolution of acute inflammation?

IL-10 and TNF-β

What is a granuloma?

A localized collection of macrophages (epithelioid histiocytes) often with central necrosis

What are examples of granulomatous diseases?

TB, histoplasmosis, sarcoidosis, foreign body reaction

What is the outcome when acute inflammation fails to resolve an infection or injury?

Chronic inflammation supervenes

What are the functions of macrophages in chronic inflammation?

Phagocytosis, cytokine secretion, antigen presentation, tissue repair, fibrosis

What are tissue-specific names for macrophages?

Kupffer cells (liver), alveolar macrophages (lung), microglia (brain), osteoclasts (bone), Langerhans cells (skin)

What type of healing attempts occur in chronic inflammation?

Angiogenesis and fibrosis

What does mixed acute and chronic inflammation indicate?

Repeated bouts of inflammation, often in autoimmune disease

What is the role of lymphocytes in chronic inflammation?

They regulate macrophage activation and promote inflammation through cytokine secretion

What is the function of dendritic cells in chronic inflammation?

Trigger antigen-specific immune responses at injury sites

What is the role of activated fibroblasts in chronic inflammation?

Produce cytokines and interact with lymphocytes to promote wound healing

Which type of lymphocyte amplifies and influences the nature of chronic inflammation?

CD4+ T lymphocytes

What is the unclear but possible role of antibodies in chronic inflammation?

Produced by plasma cells, but exact role is not well defined