1

GranulomasGranulomas•Definition•Pathogenesis•Classification•A,B,C’s of granulomas

macrophage(“epithelioid

cell”)

T-lymphocyte

multinucleatedgiant cell

Granuloma: a closely apposed collection of activated macrophages interacting with other immune cells (T-cells, sometimes eosinophils) in the process of degrading an indigestible antigen OR as a type IV hypersensitivity response

antigen

2

3

4

5

6

7

8

9

10

CD4 Th1

Th0

Th2

IFN-γ

ROS

lysosomalenzymes

granuloma

65

4

3

2

1

IL-2

IL-12

11

CD4 T-lymphocyte

macrophage

dendritic cell CD8 T-lymphocyte

eosinophil

Th2 cytokinesTh1 cytokines

GRANULOMA: generalized structure

TNF-αIFN-γIL-12iNOSIL-2

IL-4IL-5IL-10IL-13

ovum

eosinophil-richmacrophage-rich

Tuberculosis Schistosomiasis

12

13

14

15

16

17

18

19

20

21

22

23

NN

Birbeck Granule

24

25

26

27

28

29

30

Asteroid body

31

Schaumann body

32

33

34

35

36