Podcast
Questions and Answers
In the context of immunodeficiencies, which scenario most accurately describes a state where the immune system's function is compromised?
In the context of immunodeficiencies, which scenario most accurately describes a state where the immune system's function is compromised?
- An enhanced immune response leading to hyper-inflammation and tissue damage following exposure to common allergens.
- A reduced but still functional immune reaction that slows the clearance of pathogens, but prevents autoimmune reactions.
- An overactive immune system selectively targeting commensal bacteria, resulting in chronic digestive issues without increased infection risk.
- The immune system's failure to mount an adequate defense against infections and cancers, potentially leading to autoimmunity. (correct)
What key factor distinguishes primary immunodeficiencies (PIDs) from secondary immunodeficiencies?
What key factor distinguishes primary immunodeficiencies (PIDs) from secondary immunodeficiencies?
- PIDs are congenital or genetic in origin, while secondary immunodeficiencies are acquired due to other diseases or environmental factors. (correct)
- PIDs are exclusively caused by viral infections, whereas secondary immunodeficiencies result from bacterial infections.
- PIDs are characterized by an overactive immune response, whereas secondary immunodeficiencies are marked by immune suppression.
- PIDs only affect the adaptive immune system, while secondary immunodeficiencies primarily impact the innate immune system.
Which clinical scenario would most strongly suggest the need to investigate a possible primary immunodeficiency according to the 'SPUR' mnemonic?
Which clinical scenario would most strongly suggest the need to investigate a possible primary immunodeficiency according to the 'SPUR' mnemonic?
- An infant with multiple, severe infections from unusual organisms, unresponsive to standard treatments, and with a family history of early childhood deaths. (correct)
- A child with recurrent mild upper respiratory infections during the winter months, typical for their age group and daycare attendance.
- A previously healthy adult experiencing a single, severe episode of community-acquired pneumonia responding well to standard antibiotic treatment.
- An adolescent presenting with a persistent fungal skin infection that is responsive to topical antifungal medications.
In evaluating a patient for possible IEI, which infectious presentation would raise the strongest suspicion for underlying IEI?
In evaluating a patient for possible IEI, which infectious presentation would raise the strongest suspicion for underlying IEI?
Which of the following immune components primarily relies on broad recognition of pathogen classes rather than specific antigens?
Which of the following immune components primarily relies on broad recognition of pathogen classes rather than specific antigens?
How does the function of phagocytes directly contribute to preventing infection?
How does the function of phagocytes directly contribute to preventing infection?
What is the most likely infectious outcome in an individual with a deficiency in complement proteins?
What is the most likely infectious outcome in an individual with a deficiency in complement proteins?
What infection is most likely to occur as a result of antibody deficiency?
What infection is most likely to occur as a result of antibody deficiency?
What is the primary immunologic defect in Chronic Granulomatous Disease (CGD)?
What is the primary immunologic defect in Chronic Granulomatous Disease (CGD)?
What infectious complication is most commonly associated with Chronic Granulomatous Disease?
What infectious complication is most commonly associated with Chronic Granulomatous Disease?
Which of the following clinical manifestations is most closely associated with complement deficiencies, particularly those affecting early components like C1, C4, and C2?
Which of the following clinical manifestations is most closely associated with complement deficiencies, particularly those affecting early components like C1, C4, and C2?
What best describes the immunological features of Common Variable Immunodeficiency (CVID)?
What best describes the immunological features of Common Variable Immunodeficiency (CVID)?
What is a key clinical characteristic of Severe Combined Immunodeficiency (SCID)?
What is a key clinical characteristic of Severe Combined Immunodeficiency (SCID)?
Which immunological defect is most directly associated with severe combined immunodeficiency (SCID)?
Which immunological defect is most directly associated with severe combined immunodeficiency (SCID)?
Which definition describes a secondary immunodeficiency?
Which definition describes a secondary immunodeficiency?
What is the primary mechanism by which corticosteroids induce immunosuppression?
What is the primary mechanism by which corticosteroids induce immunosuppression?
Which infectious complication is most strongly associated with the use of corticosteroids at immunosuppressive doses?
Which infectious complication is most strongly associated with the use of corticosteroids at immunosuppressive doses?
Which of the conventional DMARDs presents the lowest risk of infection?
Which of the conventional DMARDs presents the lowest risk of infection?
Rituximab, an anti-CD20 monoclonal antibody, increases the risk for which infection?
Rituximab, an anti-CD20 monoclonal antibody, increases the risk for which infection?
In a patient receiving rituximab, for whom would PJP prophylaxis be most clearly indicated?
In a patient receiving rituximab, for whom would PJP prophylaxis be most clearly indicated?
What is the primary mechanism by which anti-TNFα therapies, such as infliximab, can increase the risk of tuberculosis (TB)?
What is the primary mechanism by which anti-TNFα therapies, such as infliximab, can increase the risk of tuberculosis (TB)?
Prior to initiating anti-TNFα therapy; what is the single most important step to conduct?
Prior to initiating anti-TNFα therapy; what is the single most important step to conduct?
In the South African context, which factor should prompt consideration of a non-TNFα biologic?
In the South African context, which factor should prompt consideration of a non-TNFα biologic?
Which measure has shown to have no benefit at decreasing risk of infection for patients beginning anti-TNF alpha therapies.
Which measure has shown to have no benefit at decreasing risk of infection for patients beginning anti-TNF alpha therapies.
Which of the following options are autoimmune conditions?
Which of the following options are autoimmune conditions?
Which of the following is an opportunistic infection (OI)?
Which of the following is an opportunistic infection (OI)?
Which of the following viruses should prompt you to consider the use of antivirals?
Which of the following viruses should prompt you to consider the use of antivirals?
Interleukin-6 (IL-6) has an effect on which of the following.
Interleukin-6 (IL-6) has an effect on which of the following.
There is a risk of increased TB with which of the following mediators?
There is a risk of increased TB with which of the following mediators?
Which is an illustrative example of a PID for cell-mediated immunity infections?
Which is an illustrative example of a PID for cell-mediated immunity infections?
If a baby, within the first few months of life, does not increase in weight, one should think about the disease ___________.
If a baby, within the first few months of life, does not increase in weight, one should think about the disease ___________.
What opportunistic infection is commonly seen in the gut?
What opportunistic infection is commonly seen in the gut?
Which bacteria is of concern in patients with Chronic Granulomatous Disease (CGD)?
Which bacteria is of concern in patients with Chronic Granulomatous Disease (CGD)?
Which of the following is a feature of innate immunity?
Which of the following is a feature of innate immunity?
In severe combined immune deficiency (SCID), which of the following opportunistic infections (OI) would most concern medical doctors?
In severe combined immune deficiency (SCID), which of the following opportunistic infections (OI) would most concern medical doctors?
Which of the following is considered a 'warning sign' in adults, that may indicate there is an underlying Primary Immunodeficiency?
Which of the following is considered a 'warning sign' in adults, that may indicate there is an underlying Primary Immunodeficiency?
Which of the following is an example of a live vaccine?
Which of the following is an example of a live vaccine?
Which is associated with Terminal components (C5 – C9)?
Which is associated with Terminal components (C5 – C9)?
Which of the following is a treatment for those with the Common Variable Immunodeficiency Disorder (CVID)?
Which of the following is a treatment for those with the Common Variable Immunodeficiency Disorder (CVID)?
Flashcards
Immunodeficiency
Immunodeficiency
A state in which the immune system's ability to fight infections and cancer is compromised, leading to autoimmunity.
Primary Immunodeficiency (PID)
Primary Immunodeficiency (PID)
Genetic or congenital immune disorder.
Secondary Immunodeficiency
Secondary Immunodeficiency
Immunodeficiency due to disease or environmental factors.
SPUR mnemonic
SPUR mnemonic
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Many infections?
Many infections?
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Components of the immune system
Components of the immune system
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Innate immunity cells
Innate immunity cells
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Phagocyte disorders
Phagocyte disorders
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Infections with Phagocyte disorders
Infections with Phagocyte disorders
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Complement deficiencies
Complement deficiencies
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Adaptive Immunodeficiency example
Adaptive Immunodeficiency example
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Infections with CVID
Infections with CVID
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SCID
SCID
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Adaptive immunodeficiency
Adaptive immunodeficiency
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Secondary immunodeficiency causes
Secondary immunodeficiency causes
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Corticosteroids
Corticosteroids
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Infections with Corticosteroids
Infections with Corticosteroids
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B cell depletion
B cell depletion
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Side Effects of Rituximab
Side Effects of Rituximab
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Anti-TNFα
Anti-TNFα
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Anti-TNFα and TB
Anti-TNFα and TB
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Infections with Anti-TNFα
Infections with Anti-TNFα
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Study Notes
Immune Deficiencies Overview
- Immune deficiency is a state where the immune system's ability to fight infections and cancer is compromised, often leading to autoimmunity
- Primary immunodeficiency (PID) is an inborn error of immunity (IEI)
- Secondary immunodeficiency results from another disease process or environmental factor
Suspecting Immunodeficiency
- Infections are a key indicator
- Primary Immunodeficiency is suspected with certain warning signs include
- Two or more new ear infections within 1 year
- Two or more new sinus infections within 1 year in the absence of allergy
- One pneumonia per year for more than 1 year
- Chronic diarrhea with weight loss
- Recurrent viral infections
- Recurrent need for intravenous antibiotics to clear infections
- Recurrent, deep abscesses of the skin or internal organs
- Persistent thrush or fungal infection
- Infection with normally harmless tuberculosis-like bacteria
- A family history of PI
SPUR Acronym
- SPUR aids in recognizing immunodeficiency stands for:
- Severe Infections
- Persistent Infections
- Unusual Infection e.g. organism or unusual site
- Recurrent Infections
Indicators for Immunodeficiency
- Indications to suspect immunodeficiency:
- Four or more confirmed bacterial infections per year
- Two or more pneumonias per year
- Two or more serious sinus infections per year
- Four or more new ear infections per year
- Use of multiple courses of antibiotics suggests immunodeficiency
The Immune System
- The components of the immune system are both Innate and Adaptive:
- Barriers
- Phagocytes
- NK cells
- Complement
- Cellular
- Humoral
Innate Immunity
- Innate Immunity:
- Cells: neutrophils, monocytes/macrophages, natural killer cells
- Receptors: expressed by all cells of a particular type, recognize broad classes of pathogens
- Soluble factors: complement, mannose-binding lectin, chemokines, cytokines (including IL-1, TNF-α)
- There is no change with repeated exposure to antigen
Role of Immune System
- Role of the immune system in preventing infection:
- Phagocytes: chronic granulomatous disease or congenital neutropenia result in infections such as S. aureus, S. marcescens, B. cepacia, enteric bacteria, fungal infections, and mycobacteria/nocardia
- Complement: deficiencies in the classical pathway, alternative pathway, MBL, or terminal components result in sepsis and blood-borne pathogens as well as encapsulated bacteria
- Antibody deficiency: common variable immunodeficiency (CVID) or X-linked agammaglobulinemia result in sinopulmonary or gastrointestinal infections
- Cell-mediated immunity deficiency: chronic mucocutaneous candidiasis results in infections such as skin/mucous membrane fungal infections, OI, pyogenic bacteria, or GIT viruses
- Cell-mediated + antibody deficiency: severe combined immunodeficiency (SCID) results in a wide range of pathogens including viruses, fungal infections, or OI
Chronic Granulomatous Disease
- Chronic Granulomatous Disease has several clinical presentations in infancy
- primarily affects males (50% X-linked)
- common sites of infection in the lung, skin, lymph nodes, and liver
- presents Pneumonia, abscesses, suppurative adenitis, osteomyelitis, blood stream infections, and skin infections
- Causes Growth retardation, chronic lung disease, and autoimmune conditions
- It renders prone to formation of granulomata in hollow viscus (GIT and genitourinary tract)
- Immunological defects include defects in the phagocyte NADPH oxidase complex and the failure of oxidative burst, which results in an inability of neutrophils, monocytes, and macrophages to destroy microbes
- Bacterial S. aureus, B. cepacian, S. marcescens, and nocardia infectious complications
Complement Deficiencies
- Clinical presentation in people with Complement deficiencies includes recurrent sinopulmonary bacterial infections, bacteraemia or meningitis, as well as autoimmunity
- Immunological defects include deficiencies in any component of the complement system
- Infectious complications include encapsulated organisms such as S. pneumoniae, N. meningitidis, and H. influenzae type B
Common Variable Immunodeficiency (CVID)
- CVID is characterized by impaired B cell differentiation with defective immunoglobulin production or reduced levels of IgG, combined with low levels of IgA and/or IgM
- "Variable" refers to the heterogenous clinical manifestations:
- recurrent infections
- chronic lung disease
- AI disorders
- increased susceptibility to lymphoma
- CVID is generally diagnosed before the age of 20 years, the remainder between 20-45 years
- Typically presents with bacterial sinopulmonary infections and GIT disease
- Treated with immunoglobulin replacement therapy, prophylactic antibiotics, nasal hygiene, and avoidance of live vaccines
Severe Combined Immune Deficiency (SCID)
- Clinical presentation typically occurs within first few months of life:
- failure to thrive
- recurrent infections
- persistent mucocutaneous candidiasis
- chronic diarrhoea
- Immunological defect: disturbance in the development of T and B cells caused mutations in genes essential for T-cell development and characterized by an absence of T cells
- Infectious complications include fungal and viral infections, as well as opportunistic infections and disseminated vaccine-associated disease
Secondary Immunodeficiencies
- Common causes of secondary immunodeficiencies include:
- pregnancy
- asplenia
- aging
- radiation
- toxic chemicals
- burns
- SLE
- rheumatoid arthritis IS
- immunosuppressive treatments
- chemotherapy
- HIV
- herpes viruses, mycobacterial, parasitic infection
- lymphomas
- diabetes
- CKD
- cirrhosis
- malnutrition
Corticosteroids
- Immunologic effects include decreased chemotaxis/phagocytosis, reduced cytokine production, and reduced T cell numbers/function
- Indications: anti-inflammatory and immunosuppressive
- Bind to intracellular glucocorticoid receptor
- Infectious complications include viral herpes viruses, bacterial/fungal infections, and OIs
Corticosteroid Risks
- Risk of infection is dependent on dose and duration, increases with longer courses, and is greater for >20mg with PCP PJP and TB
cDMARDs
- Methotrexate, hydroxychloroquine has no increased infection risk, and combination therapy of biologic and cDMARD hasn't been associated with additional infectious risk
bDMARDs
- Include polyclonal biological preparations such as IVIG, and monoclonal Abs
- Agents such as the Janus-associated kinase (JAK) inhibitor Tofacitinib
Anti-CD20 (Rituximab)
- Indications: B-cell malignancies or AD such as SLE or vasculitides
- Binds to CD20 producing B-cell depletion and hypogammaglobulinemia
- Causes peripheral B-cell depletion for 6-9 months
- Infectious complications include bacterial/viral infections such as Herpes viruses or Hep B/C with risk of PML and OI such as PJP
Anti-CD20 (Rituximab) - Hepatitis B
- Screen for chronic (HBsAg+) and resolved (HBcAb+) infection pre treatment.
- Give Hepatitis B if HBsAb-
- Give NA therapy to HBsAg+ and HBcAb+ individuals before, during and after treatment.
Anti-TNFα (Infliximab)
- Indications: Rheumatoid or Psoriatic arthritis, spondyloarthropathies, IBD or Sarcoidosis
- Chimeric human mouse anti-TNFa monoclonal Ab impairs monocyte differentiation, macrophage activation, and recruitment of neutrophils leading to increased infectious complications such as TB, NTMS, CAP, and Herpes viruses
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