Immunologic Diseases and Disorders

Question 1

Severe Combined Immunodeficiency (SCID)

Answer 1

ETIOLOGY:
1) X-linked recessive gene or autosomal recessive gene -> impaired lymphocyte differentiation -> expressed when weaned off mother’s lymphocytes (3-18mo)

S/S:

1) recurring infections (pneumonia, GI infections)
2) lymphoid tissue hypoplasia or aplasia

TREATMENT:
1) gene therapy (developed in 2019 by St. Judes, cohort studies show excellent prognosis thus far)

BONUS FACTS:
1) high one-year mortality rate without treatment

Question 2

HIV/AIDS

Answer 2

ETIOLOGY:
1) human immunodeficiency virus transmitted via semen, blood, lactations, vaginal secretions -> targets helper T-cells

S/S:

1) Acute HIV infection -> flu-like symptoms (myalgia, fever, lethargy)
2) Chronic HIV infection -> lymphadenopathy, weight loss, night sweats, fatigue
3) Acquired Immunodeficiency Syndrome -> T-cell count less than 200, increased risk of opportunistic infections

TREATMENT:

1) HAART Program -> nucleoside reverse transcriptase inhibitor (NRTI) with non-nucleoside reverse transcriptase inhibitor (NNRTI) OR protease inhibitor
2) prophylactic antibiotics

BONUS FACTS:
1) increased risk of encephalitis, malignancies, and dementia

Question 3

DiGeorge Syndrome/Anomaly

Answer 3

ETIOLOGY:
1) recessive gene (microdeletion of chromosome 22) -> impaired 3rd and 4th pharyngeal pouch development -> thymus gland hypoplasia and parathyroid hypoplasia

S/S:

1) downward slanted eyes, low set ears
2) recurrent infections beginning 3-18mo after birth
3) possible tetany

TREATMENT:

1) thymus gland transplant or BMT
2) vitamin D and calcium supplementation

Question 4

Wiskott-Aldrich Syndrome

Answer 4

ETIOLOGY:
1) X-linked recessive gene (mutated WAS gene) -> defective Wiskott-Aldrich syndrome protein (WASP) -> impaired erythropoietic stem cell differentiation

S/S:

1) recurrent infections (pneumonia, sinopulmonary infections, GI infections)
2) blood clotting dysfunction (petechia, purpura, epistaxis, intracranial bleeding)
3) eczema

BONUS FACTS:
1) 25-year life expectancy with splenectomy only
TREATMENT:
1) bone marrow transplant with HLA match
2) splenectomy

Question 5

Chronic Mucocutaneous Candidiasis

Answer 5

ETIOLOGY:
1) autosomal recessive gene (AIRE gene or STAT1 gene) -> impaired T-cell function -> expressed 3-18mo after birth

S/S:

1) recurrent candidiasis and other infections
2) linked autoimmune disorders

TREATMENT:
1) bone marrow transplant with HLA-match

Question 6

Common Variable Immunodeficiency (Acquired Hypogammaglobulinemia)

Answer 6

ETIOLOGY:
1) genetic factors -> impaired B-cell differentiation -> decreased circulting immunoglobulins

S/S:
1) recurrent infections (pneumonia, GI infections, sinopulmonary infections)

TREATMENT:

1) immunoglobulin replacement therapy
2) prophylactic antibiotics

Question 7

Selective Immunoglobulin A Deficiency

Answer 7

ETIOLOGY:
1) genetic factors -> impaired B cell differentiation -> impaired IgA production (others may be okay)

S/S:

1) anaphylactic reaction (aggregation) in response to IgA blood donations
2) recurrent infections (very uncommon)

TREATMENT:

1) blood donations from another IgA deficient individual
2) prophylactic antibiotics

Question 8

Bruton’s Agammaglobulinemia (X-linked Agammaglobulinemia)

Answer 8

ETIOLOGY:
1) X-linked recessive gene (BTK gene) -> defective bruton tyrosine kinase -> impaired B-cell differentiation

S/S:
1) recurrent infections (pneumonia, otitis media, sinopulmonary infections, GI infections) beginning 3-18mo after birth

TREATMENT:

1) regular immunoglobulin replacement therapy
2) prophylactic antibiotics

Question 9

Systemic Lupus Erythematosus

Answer 9

ETIOLOGY:

1) lymphocytes detect collagen as antigen -> autoantibodies produced -> inflammation of skin, joints, nervous system, and/or internal organs
2) (Exacerbating Factors) UV light, stress, inoculation, pregnancy

S/S:

1) butterfly rash on face (erythema)
2) malaise, fever, fatigue

TREATMENT:

1) corticosteroids or NSAIDs
2) immunosuppressive drugs

Question 10

Scleroderma (Systemic Sclerosis)

Answer 10

ETIOLOGY:

1) autoimmune activtity -> fibroblast activation -> scar tissue formed
2) (Exacerbating Factors)

S/S:
1) Classified into:
Localized Scleroderma (only affects skin)
Systemic Scleroderma
-> Limited scleroderma (distal limbs affected)
-> Diffuse scleroderma (trunk and internal organs affected)
2) tightening of skin, pain in joints

TREATMENT:

1) corticosteroids or NSAIDs
2) immunosuppressive drugs

BONUS FACTS:
1) 21% 10-year survival rate for dSSc

Question 11

Sjogren’s Syndrome

Answer 11

ETIOLOGY:
1) hereditary factors -> autoimmune activity against exocrine glands

S/S: xerostomia (dry mouth), keratoconjunctivitis sicca (dry eyes), other nasal and larynx dryness, difficulty talking or chewing

TREATMENT:

1) moisturizing products, sunglasses, possible surgical closure of tear ducts
2) prednisone, and/or antimalarial drugs

Question 12

Small Vessel Vasculitis

Answer 12

ETIOLOGY:
1) immune disorders, medications, infections, and certain chemicals -> autoimmune response to small vessel walls

S/S:
1) petechiae, purpura, erythema, edema, weakness, possible ocular lesions, and arthralgia

TREATMENT:
1) corticosteroids, analgesics, and avoidance of possible triggers

Question 13

Systemic Necrotizing Vasculits

Answer 13

ETIOLOGY:
1) autoimmunity or drug-induced -> inflammation and necrosis of medium and large arteries

S/S:
1) weakness, fatigue and possible angina, numbness, ischemia, dyspnea, hypertension

TREATMENT:
1) corticosteroids, analgesics, immunosuppressive drugs, plasmapheresis, possible ACE inhibitors