AISBD, amyloidosis, PLIMFD

Question 1

Causes of BP

Answer 1

1. Genetic factors
2. Drugs; triamcinolone in D (?)
3. UV light

Question 2

Pathogenesis of PB

Answer 2

binding of Ag-Ab (IgG> IgM, IgE) to collagen XVII non-collagenous domain NC16A (D, C, P, humans) → complement fixation (C3) → mast cell activation → neutrophils and eosinophils → proteolytic enzymes (gelatinase)

Question 3

Clinical DDX BP

Answer 3

PV: more flaccid vesicles
MMP: more frequent oral lesions
EBA: footpad ulcers, systemic signs (rare in BP)

Question 4

Histo DDX BP

Answer 4

1. MMP: lichenoid dermatitis, non-inflammatory blisters
2. EBA: neutrophil rich (vs eosinophil rich in BP in D and P; special stains to see eosinophils in C; absent in H); vesicles may be cell-poor
3. LAD: no eosinophils in D
4. VCLE: vesicles are more fragile

Question 5

Pathogenesis of MMP

Answer 5

a) binding of Ag-Ab (IgG, IgM, IgA) → complement activation → mast cell degranulation → recruitment of PMN cells → proteases → BMZ injury;

b) complement independent: KCs, proteases, endocytosis → BMZ injury

Question 6

IHC for EBA

Answer 6

ICH for collagen IV: it is above (or both above and below cleft) in 71% of D with EBA vs 10% of dogs with other AISEBDs

Question 7

Prognosis and th for EBA

Answer 7

1. Generalized form: may respond to glucocorticoids + azathioprine ± colchicine ± IV IgG and may be able to withdrawn treatment without relapse
2. Localized form: good response

Question 8

2 types of amyloid

Answer 8

1. Non-fibrilar: amyloid-P (from serum amyloid-P:
2. Fibrilar:
   a) amyloid-L (amino-terminal fragment of Ig light chain λ type): in primary systemic amyloidosis and in myeloma-associated amyloidosis,
   b) amyloid-A (amino-terminal fragments of serum amyloid-A: HDL, acute phase protein): in secondary systemic amyloidosis (macrophages → IL-1, IL-6, TNF → serum AA → tissue AA)

Question 9

What is the classification of amyloidosis

Answer 9

1. systemic
2. localized- organ specific - primary nodular cutaneous amyloidosis

Question 10

How can we divide systemic amyloidosis

Answer 10

1) primary (occult plasma cell dyscrasia),
2) myeloma-associated. Skin lesions: diffuse cutaneous amyloidosis,
3) secondary (chronic inflammation)

Question 11

Causes of amylidosis

Answer 11

1. Genetics
2. Chronic inflammatory disease
3. Neoplasia: plasmacytoma (D, C, H), multiple myeloma (D, C), lymphoma (H)
4. Associated with vasculitis (polyarteritis in juvenile Beagles)
5. Vaccines

Question 12

Wich ch inflammatpry diseases have been associated with amyloidosis

Answer 12

(secondary systemic amyloidosis): strangles (H), tuberculosis (H), glanders (H), cocidiomycosis (H), osteomyelitis (H), chronic purulent inflammation (H) or chronic antigenic stimulation (production of hyperimmune sera-H)

Question 13

Systemic involvement in amyloidosis

Answer 13

: kidney, liver, spleen

Question 14

Skin lesions with amyloidosis

Answer 14

1. Systemic amyloidosis with monoclonal gammopathy: haemorrhage for mild trauma
2. Mucocutaneous amyloidosis: papules, nodules (oral, footpads, interdigital, pressure points)
3. Generalized cutaneous amyloidosis: swollen footpads
4. Primary nodular cutaneous amyloidosis: nodules, ear; this form in H

Question 15

histo of MURAL MUCINOTIC ISTHMUS FOLLICULITIS AND ALOPECIA IN NORWEGIAN PUFFIN DOGS

Answer 15

Follicles: mild lymphocytic (T cells) isthmus folliculitis, mild vacuolar degeneration → follicular atrophy

Perifollicular dermis: mild mononuclear inflammation in the isthmus region, mucin, fibrosis

Sebaceous glands: may be affected (lymphocytic inflammation) → atrophy or disappearance

Question 16

Clinical signs
PROLIFERATIVE LYMPHOCYTIC INFUNDIBULAR MURAL FOLLICULITIS AND DERMATITIS WITH PROMINENT FOLLICULAR APOPTOSIS AND PARAKERATOTIC CRUSTS

Answer 16

verrucous papules and plaques, crusts, scales, follicular casts, alopecia, comedones; no or mild pruritus; head, perioral, periocular, ear pinnae, ventral abdomen, legs

Question 17

Histo of PLIMFD

Answer 17

a) apoptosis with satellitosis (follicular infundibulum, epidermis);
b) hair follicle infundibulum: acanthosis, distention due to orthokeratosis and parakeratosis forming casts and comedones;
c) papillated epidermis;
d) mixed inflammation (interface, perivascular, periadnexal, interstitial)

Question 19

th of PLIMFD

Answer 19

CsA (complete response after 4-12 months with no relapse after discontinuation in 2 dogs; complete response after 16 months with recurrence after discontinuation and no response to re-institution of CsA in 1 dog)