175.Martin Causubon weighed 3.5 kg at birth and appeared to be perfectly
normal. Through his first 2 years of life, Martin had persistent otitis media, dry
cough, and on one occasion bilateral pneumonia. At 5 months, Martin had oral
Candida spp. and a red rash in the diaper area. He was not gaining weight;
Martin was admitted to the hospital with tachypnea. His tonsils were observed
to be very small, he had hepatomegaly, and cultures of his nasal fluid grew
Pseudomonas aeruginosa. He also had coarse, harsh breath sounds from both
lungs. Blood work showed a white blood count =4800 cells μL−^1 (normal
5000–10,000 cells μL−^1 ), absolute lymphocyte count =760 cells μl−^1 (normal
3000 lymphocytes μL−^1 ). None of his lymphocytes reacted with anti-CD3;
99% of his lymphocytes bound antibody against the B-cell molecule CD20 and
1% were natural killer cells reacting with anti-CD16. His serum contained IgG
at a concetration of 30 mg dL−^1 , IgA at 27 mg dL−^1 , IgM at 42 mg dL−^1 (IgG lev-
els are normally 400 mg dL−^1 ; the IgA and IgM levels were at the low end of the
normal range for Martin’s age). His blood mononuclear cells were completely
unresponsive to phytohemagglutinin (PHA), concanavalin A (ConA), and
pokeweed mitogen (PWM), as well as to specific antigens to which he had been
previously exposed by immunization or infection—tetanus and diphtheria
toxoids, and Candidaantigen. His B lymphocytes did not react with an anti-
body to the γchain of the interleukin-2 receptor (IL-2Rγ).
The accompanying images are low magnification (A) and high magni-
fication (B) photomicrographs. In Martin’s case what would you expect to
find immediately surrounding the region labeled with the arrow?
274 Anatomy, Histology, and Cell Biology