JENNIFER KYES DVM, DACVECC

11 T H ANNUAL VET APPRECIATION DAY

OCT 29, 2017

Immune Mediated Diseases

IMMUNE MEDIATED DISEASES

�  Immune mediated hemolytic anemia (IMHA)

�  Immune mediated thrombocytopenia (ITP)

�  Non-regenerative immune mediated anemia (NRIMA)

Immune mediated diseases

� Pathogenesis � Triggers � Clinical pathology � Treatment � Prognosis

Immune Mediated Hemolytic Anemia

IMHA

�  IMHA is one of the most devastating and rapidly fatal diseases of dogs.

�  It is one of the most common conditions treated in the ICU at MOVEH.

�  Erythrocyte destruction by anti-erythrocyte autoantibodies binding to the surface of erythrocytes, targeting them for destruction

IMHA - Pathogenesis

� Primary: no underlying cause identified (70-75%)

�  Secondary: known trigger identified (25-30%)

IMHA – Triggers

�  Drug therapy (B-lactam, cephalosporins, pencillin with clavulanic acid)

�  Pre-existence of other immune mediated diseases �  Infectious diseases (tick borne infections,

mycoplasma) �  Recent vaccination (<4 weeks) �  Tissue injury (neoplasia)

IMHA - Presenting complaint

�  ACUTE �  Healthy until 24-72 hrs

prior to presentation �  Lethargy �  Collapse �  Pale gums �  Change in urine/BM colour �  Elevated body temperature

IMHA – Clinical signs

% Clinical signs 98% Pale mucous membranes 97% Weakness 80% Anorexic 46% Increased rectal temperature 44% Red urine 38% Icteric 34% Cranial organomegaly 30% Vomiting 15% Diarrhea 10% Dyspnea 3% Syncope

Recommended diagnostics

�  CBC/Chemistry/UA �  Path comment �  Saline agglutination

¡  Coombs test �  Blood typing �  4DX in dogs �  Mycoplasma in cats �  Abd + chest x-rays �  Ultrasound

BAILEY MELO-BOONE

PET OWNER: MARIA MELO-BOONESPECIES: CanineBREED: Cocker Spaniel, AmericanGENDER: Spayed FemaleAGE: 9 YearsPATIENT ID: 140637

Mississauga-Oakville VEC- ICU2285 Bristol Circle

905-829-9444ACCOUNT #: 86FATTENDING VET: Dr. Kyes

LAB ID: 1710093187ORDER ID: 104366128COLLECTION DATE: 4/18/17DATE OF RECEIPT: 4/18/17DATE OF RESULT: 4/18/17

IDEXX Services: % Band, Nucleated RBC (Reflex), CBC, Comprehensive, Smear Evaluation, Band

Hematology4/18/17 (Order Received)4/18/17 11:40 AM (Last Updated)

TEST RESULT REFERENCE VALUE

RBC 4.1 5.4 - 8.7 x10^12/L L

Hematocrit 0.27 0.38 - 0.57 L/L L

Hemoglobin 85 134 - 207 g/L L

MCV 66.7 59 - 76 fL

MCH 20.7 21.9 - 26.1 pg L

MCHC 310 326 - 392 g/L L

RDW 17.4 10 - 19 %

% Reticulocyte 10.5 %

Reticulocyte b 430.5 10 - 110 K/µL H

WBC 25.3 4.9 - 17.6 x10^9/L H

% Neutrophil 72.0 %

% Band 8.0 %

% Lymphocyte 7.0 %

% Monocyte 13.0 %

% Eosinophil 0.0 %

% Basophil 0.0 %

Neutrophil 18.2 2.9 - 12.7 x10^9/L H

Band 2 0 - 0.2 x10^9/L H

Lymphocyte 1.8 1.1 - 5 x10^9/L

Monocyte 3.3 0 - 1.2 x10^9/L H

Eosinophil 0 0 - 1.5 x10^9/L

Basophil 0 0 - 0.1 x10^9/L

Nucleated RBC(Reflex)

1 /100 WBC

Platelet 61 143 - 448 x10^9/L L

*00.0MPV 8 - 16 fl

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Complete blood count

�  Anemia (100%) �  >3-5 days

�  Regenerative �  Leukocytosis (80%) �  Bands (78%) �  Lymphocytosis �  Nucleated red blood

cells

J Vet Intern Med 2008:22:366-373

Typical Pathologist Comment for IMHA

The anemia is regenerative and considering spherocytosis, microscopic agglutination, increased polychromasia and rubricytosis, is consistent with immune-mediated hemolytic anemia.

CHESTER VAN HAREN PET OWNER: GARY VAN HAREN DATE OF RESULT: 7/15/17 LAB ID: 1710340188

Hematology (continued)

TEST RESULT REFERENCE VALUE

WBC MORPHOLOGY - Neutrophilia - MarkedWBC MORPHOLOGY - Toxic Neutrophils - ModerateRBC MORPHOLOGY - Anemia - ModerateRBC MORPHOLOGY - Polychromasia - 0-1 /100XPLT MORPHOLOGY - Normal -PLT ASSESSMENT - Platelet Count Adequate -

RBC Run

WBC Run

c Degree of bone marrow response (10E3/uL): Normal if non-anemic < 110 Inadequate if anemic < 110 Mild 110 - 150 Moderate 150 - 300 Marked > 300

Chemistry7/15/17 (Order Received)7/15/17 9:31 PM (Last Updated)

TEST RESULT REFERENCE VALUE

Glucose 4.6 3.5 - 6.3 mmol/L

IDEXX SDMA c 31 0 - 14 µg/dL H

Creatinine 51 44 - 133 µmol/L

Urea (BUN) 8.9 3.2 - 11.0 mmol/L

Phosphorus 1.4 0.8 - 2.0 mmol/L

Calcium 2.20 2.20 - 2.80 mmol/L

Sodium 150 142 - 152 mmol/L

Potassium 4.4 4.0 - 5.4 mmol/L

Na:K Ratio 34 28 - 37

Chloride 117 108 - 119 mmol/L

Total Protein 60 55 - 75 g/L

Albumin 33 27 - 39 g/L

Globulin 27 24 - 40 g/L

Alb:Glob Ratio 1.2 0.7 - 1.5

ALT 301 18 - 121 U/L H

AST 85 16 - 55 U/L H

ALP 1,006 5 - 160 U/L H

Bilirubin - Total 132.5 0 - 5.13 µmol/L H

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Biochemistry profile

Hyperbilirubinemia/-uria

Saline Agglutination Test (SAT)

NEGATIVE POSITIVE

Coombs test

�  If SAT is positive you do NOT need a Coombs.

�  Coombs is not highly sensitive or specific!!!

�  60-70% will have + Coombs

J Vet Intern Med 2008:22:366-373

Blood typing kits

POSITIVE RESULT

NEGATIVE RESULT

Blood typing

� Cannot use blood typing cards with agglutinating patients.

� Uses agglutination techniques

DEA 1.1 Positive

DEA 1.1 Negative

Canine Blood typing

Negative Dog

Negative blood

Positive blood ONCE

Positive Dog

Negative blood

Positive blood

TYPE A TYPE B

�  Always blood type! �  A to A �  Low anti-B Ab titres �  Almost all cat breeds

are type A.

�  B to B �  High anti-A titres �  Breeds that are B >25%

¡  British shorthair ¡  Cornish Rex ¡  Devon Rex ¡  Exotic ¡  Ragdoll ¡  Turkish Angora ¡  Turkish Van

Feline Blood typing

Look for underlying causes

�  4DX ¡  Heart worm, ehrlichiosis, Lyme disease, anaplasmosis

�  Chest radiographs ¡  Primary lung tumor, metastatic lung disease

�  Abdominal radiographs ¡  Zinc toxicity, neoplasia

�  Abdominal ultrasound ¡  Neoplasia, splenomegaly,

�  Mycoplasma haemofelis (cats)

Extravascular hemolysis Intravascular hemolysis

�  Removed by spleen �  Spherocytes �  Bilirubinemia �  Bilirubinuria

�  Lysed in blood stream �  Schistocytes �  Hemoglobinemia �  Hemoglobinuria

IMHA can be extravascular or intravascular

Bilirubinuria Hemoglobinuria

Urinalysis

CORE therapy for IMHA

�  Corticosteroids – PRIMARY immunosuppressant ¡  Dexamethasone - 0.25 mg/kg IV daily (inpatient) or ¡  Pred 2.2mg/kg PO daily (outpatient)

�  Anti-thrombotic ¡  Aspirin 0.5 mg/kg PO daily x 30 days

�  GI protectant ¡  Famotidine 0.5mg/kg PO q 12-24 hr

�  If you are at MOVEH …… ¡  Cyclosporine 10mg/kg daily

Other immunosuppressants

Drug Dose Dog/Cat

Azathioprine 2mg/kg PO q24hr Dogs

Chlorambucil 0.1-0.2mg/kg PO q24hr Dog, cat

Cyclophosphamide 2.2mg/kg PO q24hr Dog, cat

Human IV immunoglobulin

0.5-1g/kg IV over 6-12hr Dog

Mycophenolate 10-20mg/kg PO q12hr Dog, cat

When to PRBC transfuse?

�  >10-15% drop in PCV in <24hr �  PCVs <20% �  Clinical signs

¡  Tachycardic ¡  Dyspenic ¡  Lethargic ¡  Bounding pulses ¡  Pale mucous membranes ¡  Hyperlactatemia ¡  Collapse

Prognosis

�  Mortality rates as high as 50% in the first 3 weeks of therapy.

�  Leading cause of death is thromboembolism from hypercoagulability ¡  Acute respiratory signs - PTE ¡  Acute neurological signs – cerebral vascular event

�  No clear prognostic indicators but… ¡  The severity of agglutination ¡  The severity of hyperbilirubinemia ¡  Intravascular compared to extravascular

Long term

�  Generally prognosis is good if survive first 3 weeks.

�  PCVs normalize within a month.

�  Relapses can occur in 50% patients.

�  No longer hypercoagulable after first 30 days. ¡  Discontinue the aspirin

General weaning protocol

�  Weaning can begin when PCV has been normal for a minimum of 4 weeks.

�  Discontinue secondary immunosuppressive first ¡  Wean azathioprine by 50% every 4 weeks. ¡  Discontinue cyclosporine. No weaning required.

�  Wean prednisone by 50% every 4 weeks if PCV stable

What if patient suffers a relapse during weaning?

�  Resume the previously effective dose for 4 weeks and

consider a slower weaning protocol with a 25% reduction every 4 weeks.

Immune Mediated Thrombocytopenia

What is a platelet?

� Platelets are components of blood whose function is to stop bleeding by clumping together.

�  Injury to vessel wall triggers platelet activation within seconds.

Megakaryocytes

�  A megakaryocyte is a mass of platelets in the BM.

�  Approximately 100 billion

platelets are released every day.

�  A peripheral platelet count of 200-500 billion platelets/L of blood.

�  Platelets live only 7 days in peripheral circulation.

What is ITP?

�  IM disease causing severe thrombocytopenia

�  Anti-platelet antibodies adhere to platelet surface antigens, stimulating removal from circulation

Dogs Cats

�  59% miscellaneous �  23% infectious or

inflammatory �  13% neoplasia 5% immune mediated

�  29% infectious �  22% multiple etiologies �  20% neoplasia or

unknown �  7% cardiac disease 2% immune mediated

Thrombocytopenia is common

Immune mediated thrombocytopenia

�  More common in middle-aged female dogs �  Cocker spaniels, miniature and toy poodles, and

sheepdogs are over-represented �  Spontaneous hemorrhage develops with platelet

concentrations <30,000 cells/uL. �  Hemorrhage is unpredictable.

Clinical signs of ITP

% Clinical signs 73% Petechia 56% Ecchymosis 42% Melena 38% Gingival bleeding 35% Hematoma 23% Pale mucous membranes 23% Hyphema 19% Hematemesis 17% Hematuria 15% Epistaxis 8% Hemoptysis 7% Scleral hemorrhage

JAVMA, Vol 238, no. 3, Feb 1, 2011

ITP-Clinical signs

CBC

Biochemistry

�  Thrombocytopenia 100% ¡  <30,000

�  Anemia ¡  Mean 27%

�  Leukocytosis 31% ¡  Monocytosis 27% ¡  Bands 17% ¡  Lymphocytosis 3%

�  Elevations in ¡  BUN 19% ¡  ALP 34% ¡  ALT 12%

�  Decreases in ¡  Albumin

ITP – Diagnostics

LUCKY VOUNG

PET OWNER: LONG VOUNGSPECIES: CanineBREED:

GENDER: Spayed FemaleAGE: 5 YearsPATIENT ID: 143354

Mississauga-Oakville VEC- ICU2285 Bristol Circle

905-829-9444ACCOUNT #: 86FATTENDING VET: Dr. Kyes

LAB ID: 1710354306ORDER ID: 105839183COLLECTION DATE: 7/24/17DATE OF RECEIPT: 7/24/17DATE OF RESULT: 7/24/17

IDEXX Services: % Band, Pathologist's Comment, Nucleated RBC (Reflex), CBC, Comprehensive, Smear Evaluation, Wellness 2, Band

Hematology7/24/17 (Order Received)7/26/17 10:31 AM (Last Updated)

TEST RESULT REFERENCE VALUE

RBC 1.8 5.4 - 8.7 x10^12/L L

Hematocrit 0.13 0.38 - 0.57 L/L L

Hemoglobin 41 134 - 207 g/L L

MCV 76.6 59 - 76 fL H

MCH 23.4 21.9 - 26.1 pg

MCHC 306 326 - 392 g/L L

RDW 21.2 10 - 19 % H

% Reticulocyte 13.7 %

Reticulocyte b 246.6 10 - 110 K/µL H

WBC 13.3 4.9 - 17.6 x10^9/L

% Neutrophil 71.0 %

% Band 1.0 %

% Lymphocyte 18.0 %

% Monocyte 10.0 %

% Eosinophil 0.0 %

% Basophil 0.0 %

Neutrophil 9.4 2.9 - 12.7 x10^9/L

Band 0.1 0 - 0.2 x10^9/L

Lymphocyte 2.4 1.1 - 5 x10^9/L

Monocyte 1.3 0 - 1.2 x10^9/L H

Eosinophil 0 0 - 1.5 x10^9/L

Basophil 0 0 - 0.1 x10^9/L

Nucleated RBC(Reflex)

10 /100 WBC

Platelet 9 143 - 448 x10^9/L L

*00.0MPV 8 - 16 fl

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Doing a manual platelet count

�  In-house CBC machines can miscount giant platelets

�  Verify with a blood smear.

�  Average # platelets in 10 fields.

�  Multiple by 15 x109

Treatment for ITP

�  Corticosteroids – PRIMARY immunosuppressant ¡  Dexamethasone - 0.25 mg/kg IV daily (inpatient) or ¡  Pred 2.2mg/kg PO daily (outpatient)

�  Consider second immunosuppressant at the time of diagnosis. ¡  Cyclosporine 10mg/kg PO daily ¡  Azathioprine 2mg/kg PO daily

�  GI protectant (H2 blockers, PPI’s) ¡  Famotidine 0.5mg/kg PO q 12-24 hr ¡  Omeprazole 1mg/kg PO daily ¡  Melena is NOT caused by gastric ulceration in ITP patients.

JK’s treatment for ITP

�  Dexamethasone 0.25mg/kg IV sid ¡  Pred 2mg/kg PO sid once discharged

�  Cyclosporine 10mg/kg PO sid (or divided) ¡  IV formulation in extreme cases 4-6 mg/kg diluted CRI over 4hr.

�  H2 blocker or PPI ¡  Famotidine – 0.5mg/kg PO q12hr ¡  Omeprazole – 1mg/kg PO q12hr

�  pRBC transfusions for anemia from GI bleed. �  Platelet transfusions when life-threatening bleeding

occurs.

Blood transfusions

�  40% patients will require a transfusion

�  Give pRBC if anemic and clinical ¡  Give WB only if FRESH

�  Give PLT concentrate for life-threatening hemorrhage ¡  Brain, lungs, heart ¡  ~80 x109 platelets per unit

PROGNOSIS for ITP

Short-term survival rates 74% to 97% Recurrence rates 26% and 58% Survival to discharge 81% Mean hospital stay 6 days 1 month survival 77% >1 yr survival 1 yr survivors that lived >2yr

43% survived 70% survived

Time to recover 40,000 plt 4 days Mean time for normal platelet count 11 days % patients w/o normal platelet count 4% Median interval to complete weaning from time of diagnosis 123 days

Prognosis

�  No prognostic indictors have been identified. �  However, degree of melena may suggest poor

prognosis ¡  60% survival rate with melena vs 90% without ¡  80% patient with melena will require blood vs 26% without

melena

J Vet Intern Med 2012;26:142-148 JAVMA, Vol 238, no. 3, Feb 1, 2011

Nonregenerative Anemias

What is a nonregenerative anemia?

�  Anemia >5 days ¡  rules out pre-regenerative

anemias �  HCT<20% �  Reticulocyte count <1.0% �  2 types:

¡  Pure red cell aplasia ¡  Nonregenerative immune

mediated anemia

2 types of nonregenerative anemias

�  The difference is academic. �  Both are immune mediated conditions. �  They both take place in the bone marrow. �  They have similar CBC results. �  They are both treated with the same medications. �  They carry the same prognosis. �  Only difference is where the immune system

TARGETS the red blood cell precursor.

Pure Red Cell Aplasia Erythroid aplasia

No red cell precursors

NRIMA

Erythroid hyperplasia

Maturation arrested at Meta- or rubricyte

Presenting complaint for NRIMA/PRCA

Signs % dogs affected Duration 5 days - 3 month Lethargy 67% Weakness 28% Weight loss 16% Pica 16% Collapse 16% Exercise intolerance

9%

Vomiting 7% Fever 7% Syncope 7%

Physical exam % dogs

Pale mm 100%

Heart murmur 51%

Tachycardia 26%

Tachypnea 19%

Splenomegaly 14%

BAR 14%

Hepatomegaly 5%

Response to treatment

Response Definition # dogs Days

Complete remission

Normal Hct 10

Partial remission Hct did not reach reference range

1

Poor response No increase in Hct 2

Mean time to increase Hct 5%

38 days

Median time to remission

118 days