Lymphocyte immunophenotyping
Pagana: Mosby’s Manual of Diagnostic and Laboratory Tests, 6th Edition
AIDS (Acquired Immunodeficiency Syndrome)
Case Studies
The patient, a 30-year-old homosexual man, complained of unexplained weight loss, chronic
diarrhea, and respiratory congestion during the past 6 months. Physical examination revealed
right-sided pneumonitis. The following studies were performed:
Studies Results
Complete blood cell count (CBC), p. 156
Hemoglobin (Hgb), p. 251 12 g/dL (normal: 14–18 g/dL)
Hematocrit (Hct), p. 248 36% (normal: 42%–52%)
Chest x-ray, p. 956 Right-sided consolidation affecting the posterior
lower lung
Bronchoscopy, p. 526 No tumor seen
Lung biopsy, p. 688 Pneumocystis jiroveci pneumonia (PCP)
Stool culture, p. 797 Cryptosporidium muris
Acquired immunodeficiency syndrome
(AIDS) serology, p. 265
p24 antigen Positive
Enzyme-linked immunosorbent assay
(ELISA)
Positive
Western blot Positive
Lymphocyte immunophenotyping, p. 274
Total CD4 280 (normal: 600–1500 cells/L)
CD4% 18% (normal: 60%–75%)
CD4/CD8 ratio 0.58 (normal: >1.0)
Human immune deficiency virus (HIV)
viral load, p. 265
75,000 copies/mL
Diagnostic Analysis
The detection of Pneumocystis jiroveci pneumonia (PCP) supports the diagnosis of AIDS. PCP is
an opportunistic infection occurring only in immunocompromised patients and is the most
common infection in persons with AIDS. The patient’s diarrhea was caused by Cryptosporidium
muris, an enteric pathogen, which occurs frequently with AIDS and can be identified on a stool
culture. The AIDS serology tests made the diagnoses. His viral load is significant, and his
prognosis is poor.
The patient was hospitalized for a short time for treatment of PCP. Several months after he was
discharged, he developed Kaposi sarcoma. He developed psychoneurologic problems eventually
and died 18 months after the AIDS diagnosis.
Case Studies
Copyright © 2018 by Elsevier Inc. All rights reserved.
2
Critical Thinking Questions
1. What is the relationship between levels of CD4 lymphocytes and the likelihood of
clinical complications from AIDS?
2. Why does the United States Public Health Service recommend monitoring CD4
counts every 3–6 months in patients infected with HIV?
3. This is patient seems to be unaware of his diagnosis of HIV/AIDS. How would you
approach to your patient to inform about his diagnosis?
4. Is this a reportable disease in Florida? If yes. What is your responsibility as a
provider?
Sample Solution
The pathogenesis of acquired immunodeficiency syndrome (AIDS) is largely attributed to the decrease in T-lymphocytes bearing the CD4 receptor (CD4+). Progressive depletion of CD4+ T-lymphocytes is associated with an increased likelihood of clinical complications. Because of this association, the measurement of CD4+ T-cell levels has been used to establish decision points for initiating pneumocystis carinii pneumonia prophylaxis and antiviral therapy and for monitoring the efficacy of treatment. The United States Public Health Service (PHS) has recommended that CD4+ T-lymphocyte levels be monitored every 3-6 months in all HIV-infected persons. The need for CD4+ T-cell testing services has increased and is expected to continue to increase.
