In an HIV-positive man with Pneumocystis jirovecii pneumonia and a CD4+ T-lymphocyte count of 150 cells/µL, which CDC classification stage does he fall into?

CDC Classification Stage C3

This patient falls into CDC stage C3 1, 2.

Rationale for Classification

The CDC classification system for HIV uses two parameters:

Clinical Category (Letter)

• Category C: The patient has Pneumocystis jirovecii pneumonia (PJP), which is an AIDS-defining illness 1
• PJP is explicitly listed as an AIDS-defining opportunistic infection in the CDC classification system
• Once a patient develops any AIDS-defining illness, they are permanently classified in Category C, regardless of subsequent clinical improvement

Immunologic Category (Number)

• Category 3: CD4+ T-lymphocyte count of 150 cells/μL falls into the <200 cells/μL range 1, 2
• The CDC immunologic categories are:
  • Category 1: ≥500 cells/μL
  • Category 2: 200-499 cells/μL
  • Category 3: <200 cells/μL

Why Not Other Options?

• A2 or A3: Category A is for asymptomatic HIV or persistent generalized lymphadenopathy only - this patient has an AIDS-defining illness
• B3: Category B is for symptomatic conditions that are HIV-related but not AIDS-defining (like oral candidiasis, herpes zoster) - PJP is AIDS-defining
• C2: While the patient has Category C disease, the CD4 count of 150 cells/μL is <200, placing them in immunologic Category 3, not Category 2

Clinical Implications

With this classification, the patient requires:

• Immediate PCP treatment with trimethoprim-sulfamethoxazole (preferred) 1
• Secondary PCP prophylaxis after completing acute treatment 1, 2
• Antiretroviral therapy initiation as soon as feasible 3
• Prophylaxis can only be discontinued if CD4 count rises to >200 cells/μL for ≥3 months on antiretroviral therapy 2, 4