4 Approach To Immunodeficiency in Pediatrics
4 Approach To Immunodeficiency in Pediatrics
4 Approach To Immunodeficiency in Pediatrics
The xylose absorption test may be ordered to help determine whether a person is absorbing
carbohydrates normally and to distinguish between malabsorption disorders caused by
insufficient pancreatic enzymes or bile and those due to dysfunction of the intestines.
With the xylose absorption testing procedure, high blood and urine levels of xylose are normal.
They indicate good xylose absorption by the intestines. This suggests that the tested person's
symptoms are likely due to another cause, such as pancreatic insufficiency or bile insufficiency.
High blood levels but low urine levels may be seen in someone with kidney dysfunction. In this
case, it is the blood levels that will be used to evaluate the individual for malabsorption.
Low levels of blood and urine xylose indicate poor absorption. A variety of conditions that
affect digestion and absorption may cause decreased xylose levels. These may include bacterial
overgrowth in the intestines, parasitic infections, a shortened bowel (such as from surgery) and
celiac disease.
Hydrogen breath test
Fecal elastase is a test that measures how well the pancreas is functioning.
The fecal elastase test measures the concentration of the elastase-3B enzyme
found in fecal matter with an enzyme-linked immunosorbent assay (ELISA).
Results of this test can give a good indication of exocrine pancreatic status,
and the test is less invasive and expensive than the current "gold standard",
secretin-cholecystokinin test. Levels of fecal elastase lower than 200 μg / g of
stool indicate an exocrine insufficiency.
Alpha one antitrypsin clearance test
Short stature, fine hair, severe varicella Cartilage hair hypoplasia with short-limbed
dwarfism
1. X-linked agammaglobulinemia
2. Common variable immunodeficiency (CVID)
3. Selective IgA deficiency
4. Selective IgG subclass deficiencies
5. Hyper-IgM syndrome
X-linked agammaglobulinemia
Clinical Manifestations
Most boys with XLA remain well during the 1st 6-9 mo
of life.
They acquire infections with extracellular pyogenic
organisms
Infections include sinusitis, otitis media…...
X-linked agammaglobulinemia
Diagnosis
Lymphoid hypoplasia is found on physical examination
serum concentrations of IgG, IgA, IgM, and IgE are far below the
95% confidence limits
Levels of natural antibodies to type A and B red blood cell
polysaccharide antigens (isohemagglutinins) and antibodies to
antigens given during routine immunizations are abnormally low in
this disorder
Flow cytometry demonstrates the absence of circulating B cells.
Common variable immunodeficiency
Clinical Manifestations
Children with partial thymic hypoplasia may have little trouble with infections and grow
normally
Patients with complete DiGeorge syndrome resemble patients with severe combined
immunodeficiency
Complete DiGeorge is fatal without treatment
A T-cell count should be obtained on all infants born with primary hypoparathyroidism,
CHARGE syndrome, truncus arteriosus, and interrupted aortic arch
The immune deficiency in the complete DiGeorge syndrome is correctable by
cultured unrelated thymic tissue transplants.
Primary Combined
Antibody and Cellular
Immunodeficiencies
Severe Combined Immunodeficiency
Clinical manifestation
Affected infants present within the 1st few mo of life
recurrent or persistent diarrhea, pneumonia, otitis media,
sepsis, and cutaneous infections.
Growth may appear normal initially.
Persistent infections with opportunistic lead to death.
Affected infants also lack the ability to reject foreign tissue
and are therefore at risk for severe or fatal graft-versus host
disease (GVHD)
Severe Combined Immunodeficiency
Children with LAD-2 share the clinical features of LAD-1 but have
normal CD11/CD18 integrins.
Features unique to LAD-2 include: neurological defcts, cranial facial
dysmorphism, and absence of the erythrocyte ABO blood group
antigen.
Infections in LAD-2 are milder than that in LAD-1.
LAD-3 is characterized by a Glanzmann thrombasthenia-like bleeding
disorder.
Leukocyte adhesion deficiency