A patient with long-standing hepatitis C develops liver cirrhosis. Biopsy shows extensive collagen replacing hepatocytes, with macrophage and lymphocyte infiltration but few neutrophils. What mechanism best explains the progressive loss of liver function?
ANeutrophil-mediated necrosis of hepatocytes during recurrent acute inflammation flares
BTGF-β–driven fibroblast activation causing progressive collagen deposition that replaces functional hepatocytes with scar
CViral destruction of hepatocytes triggering regenerative hyperplasia that outpaces synthetic capacity
DGranuloma formation around infected hepatocytes, walling off large regions of functional liver tissue
HCV-driven cirrhosis is canonical chronic inflammation leading to fibrosis. The virus persists, macrophages remain continuously activated, and secreted TGF-β drives sustained fibroblast collagen deposition. This scar tissue replaces functional hepatocytes, disrupting liver architecture and destroying the mass needed for metabolism, clotting factor synthesis, and detoxification. Option A is wrong because chronic inflammation is characterized by macrophage-lymphocyte infiltrates, not neutrophils (those dominate acute). Option D (granuloma) is characteristic of tuberculosis and foreign body reactions, not viral hepatitis.
Question 2 Multiple Choice
Which cellular infiltrate best characterizes chronic as opposed to acute inflammation?
APredominantly neutrophils with fibrin exudate and edema
BPredominantly eosinophils and mast cells releasing histamine
CPredominantly macrophages and lymphocytes with ongoing cytokine secretion
DPredominantly plasma cells with immunoglobulin deposition in tissue
The cellular hallmark of chronic inflammation is the macrophage-lymphocyte partnership. Neutrophils dominate acute inflammation — they are short-lived and recruited rapidly to engulf bacteria and debris. In chronic inflammation, long-lived tissue macrophages continuously secrete TNF-α, IL-1β, IL-6, and proteases; T helper lymphocytes amplify this response via IFN-γ and provide adaptive immune specificity. Eosinophils and mast cells are more characteristic of allergic and parasitic responses; plasma cell infiltrates are a secondary feature, not the defining cellular signature.
Question 3 True / False
Chronic inflammation typically follows a period of acute inflammation that failed to resolve — it can seldom begin de novo if the immune system encounters a stimulus it cannot eliminate.
TTrue
FFalse
Answer: False
This is explicitly a common misconception. Chronic inflammation can begin immediately if the inciting stimulus is one the immune system cannot handle from the outset — certain mycobacteria (like M. tuberculosis), silica crystals, asbestos fibers, and some parasites provoke chronic inflammation directly, without a significant acute phase preceding it. The defining feature of chronic inflammation is the persistence of a non-eliminable stimulus and failure of resolution — not that it must follow an acute phase temporally.
Question 4 True / False
Fibrosis in chronic inflammation is a pathological process because it replaces functional parenchymal tissue with collagen scar that cannot perform the organ's specialized functions.
TTrue
FFalse
Answer: True
Correct. Fibrosis differs fundamentally from the limited collagen deposition in normal wound healing. In acute wound healing, collagen fills a temporary gap and remodeling eventually restores architecture. In chronic inflammation, continuous macrophage activation maintains sustained TGF-β signaling that drives ongoing fibroblast activity and progressive collagen accumulation. The resulting scar tissue is largely permanent — cirrhotic liver scar does not revert to hepatocytes; pulmonary fibrosis scar does not return to functional alveoli. This permanent replacement of specialized cells with non-functional collagen is what makes chronic fibrosis pathological rather than reparative.
Question 5 Short Answer
Why is fibrosis in chronic inflammation considered destructive rather than reparative, and what molecular signal drives its progression?
Think about your answer, then reveal below.
Model answer: Fibrosis is destructive because collagen scar replaces functional parenchymal cells — hepatocytes, alveolar epithelium, renal tubular cells — with tissue incapable of the organ's specialized tasks. Unlike acute wound healing where collagen deposition is limited and eventually remodeled, chronic inflammation provides no off-signal: persistently activated macrophages continuously secrete TGF-β, which drives ongoing fibroblast proliferation and collagen deposition. The result is progressive, largely irreversible loss of functional organ mass.
TGF-β (transforming growth factor beta) is the central profibrotic cytokine. Chronically activated macrophages secrete it constitutively; fibroblasts respond by synthesizing collagen types I and III. In liver cirrhosis, bridging collagen bands disrupt sinusoidal flow and destroy hepatocyte plates needed for metabolic function. In pulmonary fibrosis, thickened alveolar walls reduce compliance and diffusion capacity. Neither process naturally reverses — unlike the remodeling phase of acute repair, chronic fibrosis lacks the regulatory signals that terminate collagen production, explaining why the functional loss accumulates over years and is largely permanent.