Immune System & Immune Disorders

Which immunoglobulin mediates Type I Hypersensitivity reactions?

IgE

In Type I Hypersensitivity, IgE triggers the release of which primary chemical mediator from mast cells?

Histamine

Pathophysiology of Type III Hypersensitivity

Antigen-antibody complexes deposit in tissues and cause inflammation

A hemolytic transfusion reaction is a clinical example of which hypersensitivity type?

Type II (cytotoxic)

Systemic Lupus Erythematosus (SLE) and serum sickness are examples of which hypersensitivity type?

Type III (immune complex)

Which immune cells drive the response in Type IV hypersensitivity reactions?

T cells

What is the typical time delay for a Type IV hypersensitivity reaction to manifest?

48-72 hours

Which specific adrenergic receptors does epinephrine stimulate to cause vasoconstriction?

a1

What are two common cardiovascular adverse effects of epinephrine administration?

Tachycardia and hypertension

What defines the fundamental mechanism of an autoimmune disorder?

The immune system mistakenly attacks the body's own tissues.

Which autoimmune disorder is characterized by a butterfly (malar) rash and photosensitivity?

Systemic Lupus Erythematosus (SLE)

What is the primary distinction between primary and secondary immunodeficiencies?

Primary is caused by genetic defects, while secondary is acquired through disease, drugs, or environment

Which common screening test is used to detect systemic autoimmune diseases like SLE?

Antinuclear Antibody (ANA) test

What is the primary mechanism of action for Immune Checkpoint Inhibitors like pembrolizumab?

They remove inhibitory signals on T cells to enhance anti-tumor immunity

Interferon alfa-2B is primarily used to treat which types of chronic viral infections?

Chronic Hepatitis B and C

What common adverse effect complex is associated with Interferon alfa-2B therapy?

Flu-like symptoms (fever, chills, myalgia)

Which vitamin supplement is often given with methotrexate to reduce its side effects?

Folic acid

What are the two primary organs for which toxicity must be monitored during methotrexate therapy?

Bone marrow (suppression) and liver (hepatotoxicity)

What is the pharmacological class of Etanercept (Enbrel)?

TNF Inhibitor

What is the primary mechanism of action for Cyclosporine in preventing transplant rejection?

Inhibits calcineurin, blocking IL−2 production and T-cell activation.

What is the characteristic joint involvement pattern in Rheumatoid Arthritis?

Symmetric joint pain and swelling

Which organ system complication is a major concern in Systemic Lupus Erythematosus?

Renal system

Which medication is considered first-line for the long-term management of lupus?

Hydroxychloroquine

What is the pharmacological action of Filgrastim (G−CSF)?

It stimulates the production of white blood cells (specifically neutrophils)

Which leukocyte is known as a 'first responder' that performs phagocytosis at the site of an acute infection?

Neutrophils

Prior to starting a patient on etanercept, a biologic TNF inhibitor, which diagnostic test is a mandatory priority?

Latent TB screening

What is the primary clinical feature of Rheumatoid Arthritis that helps distinguish it from other joint disorders?

Symmetric joint involvement and morning stiffness lasting longer than 1 hour

What is the pathophysiology of Lupus?

ANA/anti-dsDNA leads to immune complex formation and deposition → activates complement system → inflammation

What are the signs and symptoms of Lupus?

• Butterfly (malar) rash

• Photosensitivity

• Arthritis/arthralgia

• Fatigue

• Lupus nephritis

What are the major complications associated with Lupus?

• Lupus nephritis

• Cardiovascular disease

• CNS involvement (seizures, stroke)

What is the first line treatment for Lupus?

• Hydroxychloroquine

What is the pathophysiology of Rheumatoid arthritis?

Autoimmune T cell activation → B cells/autoantibodies and macrophages get activated → TNF-a, IL-1, IL-6 → chronic synovitis → pannus formation → cartilage destruction and bone erosion

Signs and symptoms of Rheumatoid Arthritis

• Symmetric joint pain and swelling

• Morning stiffness greater than one hour

• Fatigue

• Decreased ROM

Major complications of Rheumatoid Arthritis

• Joint deformity and disability

• Increased cardiovascular risk

• Increased infection risk from the disease and being on immunosuppresents

Treatment for Rheumatoid Arthritis

• NSAIDs → symptoms relief

• Corticosteroids → acute flares

• Methotrexate → first-line DMARD

  • Helps control the disease

What is the cause of primary immunodeficiencies?

Genetic/inborn immune defect

What is the cause of secondary immunodeficiencies?

Disease, medication, or other external factor

Ex. HIV/AIDs, leukemia, chemotherapy

Methotrexate

Class: Folate antimetabolite, DMARD

MOA: decreases T-lymphocyte replication and cytokine production, causing immunosuppression and anti-inflammatory effects

Uses: RA, psoriasis, certain cancers

ADR: Bone marrow suppression, hepatotoxicity, mucositis, N/V, renal impairment, teratogenicity, folic acid deficiency

Can be administered orally, subcutaneously, or IM

What medication is used for specified methotrexate toxicity?

Leucovorin

Etanercept

Class: Biological TNF Inhibitor

Action: Binds circulating TNF, preventing TNF receptor activation, and decreases inflammation

Uses: RA, psoriatic arthritis, ankylosing spondylitis, plaque psoriasis

ADR: injection site reaction, headache, demyelinating disorders, infections

Administered subcutaneously

What type of hypersensitivity is a blood transfusion reaction?

Type II → cytotoxic

What should happen before giving the first entanercept dose?

Confirm latent TB screening

Corticosteroids

Ex. Prednisone, Methylprednisolone

MOA: Binds glucocorticoid receptors, suppressing cytokine production and T-cell activation

• Broad immune suppresion

Uses: Autoimmune diseases, allergic disorders, organ transplant rejection

Cyclosporine

Class: Calcineurin inhibitor, immunosuppressant

MOA: Inhibits calcineurin, blocking IL-2 production and T-cell activation

Uses: prevents organ transplant rejection, rheumatoid arthritis, psoriasis

ADRs: Nephortoxicity, hypertension, increased risk of infection, gingival hyperplasia