Primary Immunodeficiencies Flashcards
(146 cards)
What is the gene mutated in Ataxia Telengiectasia
ATM
What is the gene product mutated in AT? What is its role?
Ataxia telengiectasia mutated gene (ATM gene) encodes a PI3K-like serine/threonine protein kinase
Central role in activting apoptosis and cell responses to ds DNA breaks (facilitates cell cycle arrest and DNA repair)—> e.g. in response to radiation OR recomibination in lymphocytes, meiosis, telomere maintenance
What is the complex that sense ds DNA breaks and recruits ATM gene?
MRN complex
-mutations in this complex can have AT-like disorder
What are the cutaneous features of Ataxia telengiectasia?
-telengiectasias on lateral and medial bulbar conjuctivae as red symmetric horiontal streaks (around 3-6 years)
-telenegiectasias on ears, eyelids, malar prominences, antecubital/popliteal fossa and presternal area
(Less commmonly on dorsal hands, feet, jhard and soft palate)
(Non facial telengiectasias often are subtle, resembling fine petechiae)
- atrophic and sclerotic face (loss of subcutaneous fat)
- gray hairs in children and diffuse graying in adolescence
- persistent cutaneous granulomas, can ulcerate
- pigmentary mosaicism—>hyper or hypopigemnted macules, nevoid hyper or hypopigementation (likely due to chromosomal instability)
- facial papulosquamous rash
- poikiloderma
- hypertrichosis on arms
- warts
- acanthosis nigricans
What is the first manifestation of AT?
Ataxia-appearing when they start to walk, but often not diagnosed until skin findigns around age 6
Name 5 non cutaneous features of ataxia-telengiectasia syndrome
- Ataxia
- swaying of head and trunk - Immune deficiency/ frequent sinopulmonary infections
- Chromsomal instability with persistent dna damage after radiation
- Premature aging
- Progressive neurological deterioration
- choreoathetosis, dysarthria, oculomotor abnormalities, myoclonic jerks - Mask-like facies (progeric change)
- Glucose intolerance/insulin resistance
- Growth retardation
- Intellectual disabilit
- Hypogonadism
- Lymphoid neoplasia
- leukemia, lymphoma especially
What is most common cause deathin AT?
Respiratory failure and bronchiectasis
What do carriers of AT have an increase risk of?
Breast cancer and likelihood of death from cancer (stomach, cololon, lung, breast)
Name 6 laboratory findings in AT
- DEcreased IgE, IgA, IgG (Ig2 and 4 esp),
- Low molecular weight IgM and increased IgM in some
- Elevated AFP and CEA
- Elevated liver enzymes
- Lymphopenia
- Decreased CD4+ T-cells, increased gamma-delta T cells
- Increased IL-8
Name 4 differential diagnoses of AT?
- FRiedrichs ataxia-no telengiectasis
- Bloom-no neuro abnormalities but can present with CALMS, telengiectasias (facial, sometimes conjuctival), decreased IG levels, recurrent resp infections, heme maligancies
- FILS syndrome (facial dysmorphism, immunodeficiency,livedo, short stature, due to POLE-1 mutations —> can have telengiectasias or poikiloderma
- RIDDLE syndrome-radiosensitivity, immune deficiency, facial Dysmorphism, difficulty learning, abnormal motor control and short stature (also has to do with site of dsDNA break repair)
What is the mode of transmission in AT?
AR
What is the median lifespan of patients with AT?
25 years +
Name 5 treatments for AT (not directed, supportive)
Abx, prophylaxis and IVIG
Sun protection
Physical therapy
Screening for malignancy
Chest physio. +- steroids for lungs
Antioxidants (alpha lipoic acid)
Which interleuken response deficiency plays a role in chronic mucocutaneous candidiasis
IL-17
Name 9 variants/subtypes of CMC?
- Non syndromic CMC
- APECED (autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome)
- CMC due to increased STAT-1 signalling
- CMC + suscpeibility to mycobacterial infections
- CARD9-associated CMC
- Decin-1 deficiency
- Candidal granuloma
8,. Late onset CMC - Familial chronic nail candidiasis
- CMC associated with other immune deficiency disorders (multipl
- CMC associated with metabolic disorders
Which biologics through what mechanism can also cause recurrent candidiasis?
Ixekizumab
Secukinumab
(IL-17A=free floating cytokine)
Brodalumab (IL-17 RA=receptor A)
What is the role of STAT-1 and STAT-3 in candida immunioty
JAK-STAT3 responds to Il-12/23 receptor activation —> upregulated retinoic acid receptor related orphan recptor (RORC) —> leads to IL-17A, IL-17F and Il-22 production and thus activated IL-17 receptor = somehow internally causes candidal death?
STAT-1 actually repressesIL-17 production
What is the mode of transmission of APECED?
AR
What is the gene mutated in APECED
AIRE gene
What is APECED
Autoimmune polyendocrinop[athy-candidiasis-ectodermal dystrophy syndrome
What are 6 clinical featuers of APECED
Mucocutaneous candidal-mean onset age 3
Candidal granulomas-face and scalp
Autoimmune endocrinopathies (can be teen or adult)
- hyperpara MC
- hyperadrenocorticisms
- hypogonadism
- thyroid
- t1DM
- hypopit
Cutaneous autoimmune d/o
- AA
- vitiligo
- urticarial eurption
- lupus like panniculitis
Other autoimmune:
- low B12 from pernicious anemia
- hepatitis
- pneumonitis
- sjogren like
Dental enamel hypoplasia, chronic diarrhea, keratoconjuctivitis, hyposplenism, htn, oral/esophageal SCC
Anti-type I interferon antibodies (antithyroglobulin, anitmicrosomal, antiparietal, antiadrenal antibodies, RF)
What gene (s) is mutated in CMC disease? Transmission pattern?
IL17F= AD mutation (cytokine)
IL17RA or RC = AR mutation in receptor
TRAF3IP2 and ACT-2 = TRAF3 interacting protein 2 —> adaptor protein ACT1 intracellularly attached to IL17 receptor
What are 4 clinical features CMC disease
ORal candidiasis 6 mo-2 years
Cutaneous and ungual candidiasis common
NO endocrinopathies
Cutaneous staph infections (IL17RA or TRAF3IP2)
Name 10 clinical features CMC due to increased STAT1 signalling (including gene and transmission)
AD-gain of function STAT-1 (Stat 1 inhibits IL-17 production)
Mucocutaneous cndida around 1 year-oropharynx>nails > skin (50%)
Dermtophyte infections skin and or nails
Cutaneous AI d/o vitiligo, AA
Autoimmunity:
- thyroid
- t1dM
- cytopenias
- celiac
- SLE
Other infections variable-staph, bacterial PNA, viral, mycobacterial
Aneurysms
Mucocutaneous SCC