Immunopathology

1. Immunopathology SYLLABUS: RBP(Robbins Basic Pathology) Chapter: Diseasesof immunity

2. Immunopathology • Polyarteritis nodosa 108aGlomerulonephritis • Rheumatic myocarditis 209Hashimoto thyroidits

3. Polyarteritis nodosa • early phase: degeneration of arterial wall with fibrin deposition and partial or complete destruction of external and internal elastic laminae • inflammatory infiltration within and around vessels predominantly composed of PMNs with leukocytoclasia (fragmentation of their nuclei) • intermediate phase: intimal proliferation, thrombosis, and chronic inflammation in vessels and perivascular tissue • healed phase: fibrosis and recanalization

4. Polyarteritis nodosa

5. Polyarteritis nodosa

6. Glomerulonephritis • Possible lesions: • diffusely enlarged hypercellular glomeruli • mesangial cell proliferation • infiltrating leukocytes • lobular accentuation • thickening of glomerular capillary wall

7. Glomerulonephritis

8. Glomerulonephritis

9. Rheumatic myocarditis • Aschoff bodies: • foci of swollen eosinophilic collagen • surrounded by lymphocytes (primarily T cells), occasional plasma cells, and Anitschkow cells (pathognomonic for RM plump macrophages with abundant cytoplasm and central round-to-ovoid nuclei with the chromatin disposed in a central, slender, wavy ribbon ("caterpillar cells") • larger macrophages become multinucleated to form Aschoff giant cells

10. Rheumatic myocarditis

11. Rheumatic myocarditis

12. Hashimoto thyroidits • lymphocytic infiltration of parenchyma with follicles and prominent germinal centers • plasma cells, histiocytes, and scattered multinucleated giant cells may be present • small, atrophic follicles with widespread Hürthle cell change (epithelial cells distinguished by the presence of abundant eosinophilic, granular cytoplasm) • in about 12% of case extensive fibrosis (fibrous variant)

13. Hashimoto thyroidits

14. Hashimoto thyroidits