Mycobacterium tuberculosis Complex DNA detection in
Immunocompromised Patient

A female in her mid 50s presented with generalized lymphadenopathy, clinically suspicious for lymphoma. A lymph node biopsy was obtained, and representative samples were sent for flow cytometry and fixed in formalin for routine histologic examination. Because the lymphadenopathy was thought to be due to lymphoma, no fresh tissue was submitted for culture.

The flow cytometry demonstrated abundant cellular debris and a decreased CD4:CD8 ratio of 0.1, but no abnormal B or T cell populations. The decreased CD4:CD8 ratio raised the possibility of HIV infection, and subsequent testing was positive.

Histologic sections of the lymph node demonstrated necrotizing granulomata, and bacilli were identified with an acid fast stain. In the context of relatively advanced HIV, the acid fast bacilli were thought to represent M avium / intracellulare complex (MAI), and the patient was discharged with antibiotics to cover MAI. In addition, a representative block of paraffin-embedded tissue was sent for PCR analysis.

Mycobacterium tuberculosis complex DNA was detected in PET by PCR.

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