1. AMYLOIDOSIS.
Extra cellular deposition of fibrillar proteinaceous substance; amyloid.
Misnomer= meaning starch-like;
Affected organs
C/S stained brown with iodine.
Turns violet on addition of
sulphuric acid.

2. Nature:
- Light microscopy: HE staining- structureless, eosinophilic hyaline material.

3. Electr. Microscopy & chemical analysis:
Composed of 2 main complex proteins:
i. Fibrillar proteins- 90 % of amyloid.
ii. P-component- 10 %.

4. Fibril Proteins:
Delicate, non- branching filaments.
Lying singly or 1-4 laterally aligned aggregates.
Size nm diameter.

5. Fibrils further composed of proto-fibrils, each 2.5-3.5 nm diameter.
X-ray crystallography analysis reveals Beta- pleated sheet configuration.
Hence also known as Beta-fibrillosis.

6. Chemical nature:
Through solubilization in 6 M- solution of guanidine hydrochloride solution.
2 major forms of amyloid:
AL (Amyloid light chain) protein.
AA (Amyloid associated) protein.

7. I. FIBRIL PROTEINS:
AL PROTEIN:
Composed of polypeptides Mwt
Made up of whole immunoglobulin light chains or fragments
Either kappa or lambda light chains.

8. The fibril protein is produced by immunoglobulin secreting cells.
Seen in association with plasma cell dyscrasias.
Include multiple myeloma, secreting Bence Jones protein.

9. AA PROTEIN:
Composed of polypeptides Mwt 9500, having 76 aminoacids.
Derived from large precursor protein in serum- SAA (serum amyloid associated protein Mwt ).

10. SAA circulates in association with HDL3 ( High Density Lipoprotein).
SAA is an acute phase reactant protein synthesized in liver.
Levels high in chronic inflammatory and traumatic conditions.

11. Found in different clinical states: a. Transthyretin (ATTR)-
OTHER PROTEINS:
Found in different clinical states:
a. Transthyretin (ATTR)-
transports thyroxine and retinol normally.
A variant deposited in familial amyloid polyneuropathy and senile amyloidosis.

12. b. Beta-2 microglobulin (AB2m)- a normal component of major histocompatibility complex (MHC).
c. Beta-2 amyloid protein (AB2)- seen in cerebral plaques and blood vessels in Alhzeimer’s disease.
d. Hormone precursor eg procalcitonin and pro-insulin ( amyloid endocrine)

13. II. P-COMPONENT:
Synthesized by liver.
Present in all forms of amyloid.
EM shows pentagonal profile hence P-component.
Chemical analysis= glycoprotein Mwt 200,000.

14. Resemble normal serum alpha-1- glycoprotein.
Structurally related to C-reactive protein and acute phase reactant but not similar.

15. PATHOGENSIS OF AMYLOIDOSIS.
Basis: an immunologic mechanism.
Not a single disease.
Different mechanisms involved.

16. Deposition of AL amyloid:
Stimulus- disorder of immunoglobulin synthesis; multiple myeloma, B cell lymphomas etc.
Excessive Ig synthesis in form of monoclonal gammopathy.
Partial degradation in form of limited proteolysis of protein molecule.

17. This occurs in macrophage anatomically closely associated with AL amyloid.
The role for serum amyloid P component and glycosaminoglycans unknown.

18. Deposition of AA amyloid.
Directly related to SAA levels.
SAA elevated in chronic inflammation.
Synthesis in liver in response to cytokine response; IL-1 and IL-6.
Partial proteolysis in reticulo-endothelial cells.

19. Amyloid enhancing factor (AEF) elaborated in chronic inflammation, cancer, and Familial Mediterranean fever.
This factor is essential for AA amyloid formation.
Role for P component here also unknown.

20. a. Primary ( Mesenchymal) or Secondary amyloidosis.
Classification:
Many classifications.
a. Primary ( Mesenchymal) or Secondary amyloidosis.
b. Histological classification:
Pericollagenous= primary.
Peri-reticulin= secondary.

21. c. Clinical location:
i. involving tongue, heart, bowel, skeletal etc.
ii. involving liver, spleen and kidney.
iii. mixed pattern (1&2)

22. d. Clinico-pathologic classification-widely used.
1. Systemic ( generalized) amyloidosis.
a. Primary
b. Secondary (reactive).
c. Haemodialysis associated.
d. Heredofamilial.

23. 2. Localized amyloidosis
a. Senile cardiac.
b. Senile cerebral.
c. Endocrine.

24. SYSTEMIC AMYLOIDOSIS
Primary Systemic amyloidosis:
Fibrils –light chain Ig or fragments- AL amyloid.
30 %of patients have plasma cell dyscrasia such as multiple myeloma, B cell lymphoma
70 % have B cell proliferative disorder or associated disease ( primary or idiopathic).

25. Often severe in heart, bowel, skin, muscle or abdominal viscera.

26. Secondary ( Reactive) systemic amyloidosis.
Fibrillar proteins- AA amyloid.
Occurs in chronic infections such as tuberculosis
Distribution – solid abdominal viecera: liver, spleen. Kidneys and adrenals.

27. Haemodialysis associated amyloidosis:
Occurs in patients on long term dialysis.
Deposition- synovium of joints and tendon sheaths .

28. Heredo-familial amyloidosis. i. Familial Mediterranean Fever.
Autosomal recessive disease.
Common in people of Mediterranean origin.
Features periodic fevers and polyserositis ( pleura, synovium, peritoneum).
Nature= AA type due to chronic inflammation.

29. ii.Hereditary polyneuropathic amyloidosis.
Autosomal dominant disease.
Deposition peripheral and autonomic nerves.
Features: weakness, pain and paraesthesias
Derived from transthyretin.

30. Staining characteristics:
a. H&E: extracellular eosinophilic material.
b. Metachromatic stains.
- Reacts with dyes with colour change.
- Methyl or crystal violet- rose pink colour.
c. Congo Red and Polarized light:
- Turns to orange colour.
- Under polarized light

31. microscopy , it shows green birefringence .
Fluorescent Stains- Thioflavin T.
Sulphated alcian blue : turns blue- green colour.

32. Pathology:
Various organs affected;
Kidney= glomerular hyalinization, tubular atrophy with vascular involvement.
Spleen:
1. Sago-spleen.
2. Lardaceuous spleen. C/S map-like areas.
Prognosis: progressive disorder with organ destruction.