Pathology

The histologic hallmark of sarcoidosis is the presence of discrete, noncaseating, epithelioid cell granulomas typically at different stages of development (Table 1, Figure 1). The dominant cell in the central core is the epithelioid cell, thought to be a differentiated form of a mononuclear phagocyte. CD4' lymphocytes and mature macrophages are typically interspersed throughout the epithelioid core, whereas both CD4 and CD8 "" lymphocytes are seen in the periphery of the granuloma. Approximately 5-10% of T cells at sites of inflammation are IL-2R' and 20-50% are HLA-DR+, indicative of their recent activation.

Stimulus

(A) Acliviilon and proUeration

Stimulus

(A) Acliviilon and proUeration

Rcsolufon
Chronic lung inflammation and lymphodcnopalhy

(C; Resolution vs chronic inflammation

Figure 1 Principal events involved in granuloma formation in sarcoidosis. (A) In response to an unknown stimulus, activated macrophages and oligoclonal CD4~ T cells accumulate at sites of inflammation. (B) Epithelioid cells and giant cells, derived from differentiated macrophages, aggregate with fibroblasts, other CD4 and CD8 T cells and mononuclear phagocytes to form granulomas. These events are hypothesized to be driven by antigen-specific, TH1 -mediated immune responses that produce type 1 cytokines (IFN-y, IL-2, IL-12), TNFa and other proinflammatory chemokines and cytokines. (C) Granuloma formation may resolve spontaneously or persist, leading to chronic inflammation and fibrosis.

How To Bolster Your Immune System

How To Bolster Your Immune System

All Natural Immune Boosters Proven To Fight Infection, Disease And More. Discover A Natural, Safe Effective Way To Boost Your Immune System Using Ingredients From Your Kitchen Cupboard. The only common sense, no holds barred guide to hit the market today no gimmicks, no pills, just old fashioned common sense remedies to cure colds, influenza, viral infections and more.

Get My Free Audio Book


Post a comment