Question

Peter is an 18-month-old boy that was born after an uneventful pregnancy.  He weighed 6 lbs 12 oz at birth and was 21.4 inches long. Soon after going home, he developed a persistent ear infection that was finally cleared after a 30-day course of antibiotics. At 2-months-old and again at 8-months-old, Peter was admitted to the pediatric intensive care because of aggressive Haemophilus influenzaepneumonia. When he was 12-months-old he developed a severe case of strep throat. In each case, the infections were cleared after antibiotic therapy.  In short, Peter seemed to develop one persistent bacterial infection after another throughout his short life although he did not develop viral infections at an abnormally high rate. In addition, he has failed to thrive and is unusually small for his age despite being of normal size at birth. He has received all of his age-appropriate immunizations on the normal schedule and without incident. Finally, Peter has two older sisters (3 years-old and 5 years-old) neither of which suffered from chronic infections during their childhood.  His pediatrician suspects Peter suffers from a specific condition and orders a functional immunology screen.  The table below indicates the results of this panel:

Quantitative serum immunoglobulins (g/L)
	Measured	Normal
IgG	1.24	[5.5-10.0]*
IgM	0.12	[0.4-1.8]
Antibody activity
Immunization responses
Tetanus toxoid - no detectable IgG antibodies
Diphtheria toxoid - no detectable IgG antibodies
Polio - no IgG antibodies detected
Measles - no IgG antibodies detected
Rubella - no IgG antibodies detected
Blood lymphocyte subpopulations (x109/l)
Total lymphocyte count	4.5	[2.5-5.0]
T lymphocytes (CD3+)	2.9	[1.5-3.0]
B lymphocytes (CD23+)	0.22	[0.1-0.4]

What do you suspect is wrong with Peter? Be specific.

Answer 1

Correct answer:

Peter is having immune deficiency...

Rational:

1. Peter serum immunoglobulin G level is not in normal level, indicates deficiency of IgG that causes the immuno deficiency.

2. Peter immunisation response also clearly states the deficiency of immunoglobulin G that also results in immnuno deficiency.

3. Peter is having frequent infections due to this immuno deficiency.

4. So I am suspecting immuno deficiency with Peter.