Chapter 26 Immunoglobulin Therapy

Question 1

What is the main purpose of immunoglobulin administration in equine practice?

Answer 1

To provide passive immunity, manage infectious diseases, and offer immunomodulation for conditions like immune-mediated thrombocytopenia.

Question 2

What are the forms of immunoglobulin products used in equine therapy?

Answer 2

Plasma, serum, or concentrated immunoglobulin proteins.

Question 3

What conditions indicate the use of immunoglobulin therapy in horses?

Answer 3

Failure of passive transfer, prophylaxis from infectious diseases, management of infectious gastrointestinal diseases, hypoproteinemia, endotoxin neutralization, and immune-mediated thrombocytopenia.

Question 4

What document aids equine practitioners in selecting immunoglobulin products?

Answer 4

The AAEP Biologics and Therapeutic Agents Committee’s White Paper on Equine Plasma and Serum Products.

Question 5

Why is the use of licensed products preferred over non-licensed ones in immunoglobulin therapy?

Answer 5

Licensed products ensure safety, efficacy, and regulatory compliance, whereas non-licensed products lack regulatory oversight.

Question 6

What should practitioners do if they are uncertain about the licensing process for immunoglobulin products?

Answer 6

Contact the USDA Center for Veterinary Biologics or visit their website for information.

Question 7

What are the main advantages of using fresh-frozen plasma in neonatal foals with failure of passive transfer?

Answer 7

Increases circulating IgG concentration, provides bactericidal and neutralizing activities, and improves cardiovascular stability.

Question 8

What is the target IgG concentration in neonatal foals receiving plasma for failure of passive transfer?

Answer 8

Above 800 mg/dL, ideally above 1000 mg/dL.

Question 9

What are the primary pathogens against which immunoglobulins provide protection in foals with failure of passive transfer?

Answer 9

Gram-negative bacteria.

Question 10

What is the standard dose of fresh-frozen plasma for a foal with partial failure of passive transfer?

Answer 10

20 mL/kg, approximately 1 L of plasma per 50 kg foal.

Question 11

What are the potential adverse reactions during plasma transfusion in foals?

Answer 11

Elevated respiratory rate or effort, tachycardia, pyrexia, and hypersensitivity reactions.

Question 12

When should circulating IgG concentration be re-evaluated after plasma transfusion in foals?

Answer 12

Approximately 2–4 hours following the transfusion.

Question 13

What conditions might necessitate repeat plasma transfusions in foals?

Answer 13

Ongoing sepsis and pathogen challenge.

Question 14

What is the purpose of administering immunoglobulins to septic equine patients?

Answer 14

To neutralize circulating endotoxin and manage systemic inflammatory response.

Question 15

What are the key components of endotoxin in Gram-negative bacteria?

Answer 15

Lipopolysaccharide (LPS).

Question 16

What are the clinical signs of endotoxemia in horses?

Answer 16

Altered core body temperature, tachycardia, injected mucous membranes, prolonged capillary refill time, and intestinal hypomotility.

Question 17

What severe complications can arise from endotoxemia in horses?

Answer 17

Disseminated intravascular coagulation, vascular thrombosis, and laminitis.

Question 18

What types of plasma products are preferred for endotoxemic patients?

Answer 18

Products originating from horses hyperimmunized against Salmonella and E. coli.

Question 19

What additional proteins in fresh-frozen plasma benefit septic equine patients?

Answer 19

Albumin, protein C, fibronectin, and antithrombin.

Question 20

Why is fibronectin important in managing septic equine patients?

Answer 20

It aids in the clearance of immune complexes, damaged platelets, and particulate matter, stabilizes blood clot organization, and facilitates wound healing.

Question 21

What is the significance of antithrombin in treating septic horses?

Answer 21

Provides anticoagulant and anti-inflammatory properties, and its restoration is crucial for managing coagulation disorders.

Question 22

What is a potential risk of combining heparin with antithrombin in plasma transfusion?

Answer 22

Heparin may attenuate the anti-inflammatory effects of antithrombin.

Question 23

What is the recommended treatment for hypoproteinemic equine patients?

Answer 23

Human albumin has been reported as a safe and efficacious colloidal therapy, though large-scale clinical trials are lacking.

Question 24

What adverse reactions can occur with the use of human albumin in equine patients?

Answer 24

Facial swelling and delayed-type hypersensitivity reactions.

Question 25

What is the primary aim of administering hyperimmune plasma against Rhodococcus equi in foals?

Answer 25

To prevent R. equi-associated pneumonia on endemic farms.

Question 26

What are important considerations for administering hyperimmune plasma for Rhodococcus equi prophylaxis?

Answer 26

Administer at least 1 L of licensed hyperimmune plasma no later than the second day of life, with a possible additional liter at 14–32 days of age.

Question 27

What is the role of intravenous immunoglobulin (IVIg) therapy in treating immune-mediated thrombocytopenia (IMT) in horses?

Answer 27

Dilutes and removes antibodies targeted against platelet surface proteins, providing therapeutic benefit.

Question 28

What is the recommended dose of plasma for treating IMT in horses?

Answer 28

20 ml/kg/day for 2–5 days.

Question 29

What are the multifaceted mechanisms of treatment success with high-dose plasma transfusion for IMT?

Answer 29

Blocked Fc receptor binding, steric hindrance of immune complex adherence, enhanced T-lymphocyte suppressor activity, and reduced B-lymphocyte function.

Question 30

What is the main immunologic benefit of immunoglobulin therapy in horses with hypoproteinemia?

Answer 30

Provides essential proteins, increases oncotic pressure, and improves cardiovascular stability.

Question 31

What are the potential risks associated with the administration of immunoglobulin therapy?

Answer 31

Immediate or delayed hypersensitivity reactions, hypocalcemia, intravascular volume overexpansion, and hepatic necrosis.

Question 32

Why is close patient monitoring imperative during immunoglobulin therapy?

Answer 32

To detect and manage potential adverse hypersensitivity reactions.

Question 33

What is the significance of using licensed immunoglobulin products?

Answer 33

Ensures the product is harvested from healthy donors free from infectious diseases, and adheres to regulatory standards for safety and efficacy.

Question 34

What are the clinical signs of a hypersensitivity reaction to plasma transfusion?

Answer 34

Elevated respiratory rate or effort, tachycardia, pyrexia, and anaphylaxis.

Question 35

What is the effect of ongoing sepsis on the half-life of circulating antibody proteins from plasma transfusion?

Answer 35

Results in enhanced catabolism and an abbreviated half-life of circulating antibody proteins.

Question 36

What is the purpose of hyperimmunizing donor horses for plasma products?

Answer 36

To ensure high levels of specific antibodies against targeted pathogens, providing effective prophylaxis and treatment.

Question 37

What is the role of antithrombin in managing coagulopathies in septic horses?

Answer 37

Restores depleted antithrombin levels, providing anticoagulant and anti-inflammatory effects.

Question 38

What are the benefits of fresh-frozen plasma in managing endotoxemia?

Answer 38

Neutralizes endotoxins, provides essential proteins, and improves coagulation and inflammatory profiles.

Question 39

What are the potential benefits of using immunoglobulin therapy in equine patients with severe gastrointestinal diseases?

Answer 39

Regulates altered coagulation profiles, balances inflammatory pathways, and improves overall patient stability.

Question 40

What is the impact of fibronectin on the immune response in septic equine patients?

Answer 40

Facilitates the clearance of immune complexes and stabilizes blood clot organization, aiding in the resolution of systemic inflammation.

Question 41

What is the recommended dose of fresh-frozen plasma for foals with complete failure of passive transfer?

Answer 41

Up to 2 L to achieve adequate IgG levels.

Question 42

What are the clinical indications for using hyperimmune plasma against Streptococcus equi in horses?

Answer 42

Treatment of Streptococcus equi infections, including Strangles.

Question 43

What is the role of endotoxin-neutralizing immunoglobulins in managing Gram-negative sepsis?

Answer 43

Reduces the expression and signaling of inflammatory mediators, improving clinical outcomes.

Question 44

What is the therapeutic effect of immunoglobulin therapy in immune-mediated thrombocytopenia?

Answer 44

Dilution and removal of antibodies targeted against platelet surface proteins, enhancing platelet survival.

Question 45

What is the potential adverse reaction of hepatic necrosis associated with plasma therapy called?

Answer 45

Theiler’s disease.

Question 46

What are the clinical outcomes of using human albumin as a colloidal therapy in equine patients?

Answer 46

Safe and efficacious, though adverse events like hypersensitivity reactions may occur.

Question 47

What is the importance of administering immunoglobulin therapy prior to pathogen challenge in foals?

Answer 47

Provides protection against infections, reducing morbidity and mortality during the perinatal period.