questions 2

Leukocyte Adhesion Deficiency

Topic updated on 01/19/17 8:01pm

  • A baby girl is born to a G1P1 mother with no complications. On day 4 of life, she develops a fever. There is some swelling with serosanguinous fluids around her rectum. Cultures from the fluid grow Staph spp. She is treated with antibiotics. On day 15 of life, she develops an ear infection and is once again treated with antibiotics. The umbilical cord is still attached. On day 34 of life, the umbilical stump is noted to be erythematous, indurated, and tense. Now suspicious of a primary immunodeficiency disorder, the physician orders a CBC, which returns with elevated leukocytosis. Immunoglobulin levels are normal. Flow cytometry reveals decreased expression of CD18 to < 1%.
  • Failed leukocyte extravasation in Leukocyte Adhesion DeficiencyPrimary immunodeficiency resulting from phagocytic dysfunction
  • Genetics
    • autosomal recessive
    • absence of CD18 expression
  • Epidemiology
    • very rare
    • primarily seen in pediatric population
  • Pathogenesis
    • defect in LFA-1 integrin (CD18) protein on phagocytes
    • normal physiology
      • CD11a/CD18 (LFA-1 integrin) expressed on lymphocytes are important in
        • trafficking and adhesion to vascular endothelium
        • interactions with antigen presenting cells
        • cytotoxic T-cell killing
    • results in impaired migration and chemotaxis
  • Prognosis
    • 75% of individuals have severe disease, with typically <1% expression of CD18
      • may succumb to life-threatening infection within 1-2 years of life
    • mild disease, with 1-30% expression of CD18
      • survive to adulthood
  • Symptoms
    • delayed separation of umbilical cord at birth to > 30 days
    • omphalitis
    • recurrent infections of skin and mucosa
      • most commonly Staph spp., enteric gram-negative bacteria, and fungal
      • perirectal and labial cellulitis
      • otitis media
    • absent pus formation
      • serosanguineous fluids may be present
    • impaired wound healing
      • poorly formed, thin, bluish scars
    • gingivostomatitis
  • ↑ Neutrophils in the absence of infection
    • dramatically ↑ with infection
  • Histology
    • localized infection with absence of neutrophils or pus
    • edema and necrosis
  • Flow cytometry
    • absence of CD18 on leukocytes
 Differential Diagnosis
  • Chédiak-Higashi syndrome
  • Chronic granulomatous disease
  • Hematopoietic stem cell transplant
    • high success rate
  • Prophylactic antibiotics
  • Life-threatening infections
  • Graft versus host disease after stem cell transplant


Qbank (2 Questions)

(M1.IM.6) Which of the following patient presentations would be expected in an infant with defective LFA-1 integrin (CD18) protein on phagocytes, in addition to recurrent bacterial infections? Topic Review Topic

1. Eczema and thrombocytopenia
2. Skin infections with absent pus formation, delayed umbilicus separation
3. Cardiac defects, hypoparathyroidism, palatal defects, and learning disabilities
4. Chronic diarrhea, oral candidiasis, severe infections since birth, absent thymic shadow
5. Progressive neurological impairment and cutaneous telangiectasia

(M1.IM.74) A 5-month-old is brought to the pediatrician by her mother because of concerns about her health. The mother states that since birth she has had recurrent bacterial infections despite every effort to maintain adequate hygiene to prevent infection. Upon questioning, the mother notes that while the child had an uncomplicated birth, she did have an abnormally delayed separation of her umbilical cord. The pediatrician decides to pursue further workup. Which of the following images is most likely to be observed during the course of this workup? Topic Review Topic
FIGURES: A   B   C   D   E  

1. Figure A
2. Figure B
3. Figure C
4. Figure D
5. Figure E


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