Granuloma formation in patients receiving BCG immunotherapy

Area of Science:

• Immunology
• Oncology
• Pathology

Background:

• Bacillus Calmette-Guérin (BCG) is an immunotherapy used in cancer treatment.
• BCG can induce granulomatous inflammation.
• The systemic effects of intravenous BCG in leukemia patients require investigation.

Purpose of the Study:

• To investigate the occurrence and extent of granuloma formation following repeated intravenous BCG administration in acute myeloblastic leukaemia (AML) patients.
• To assess the clinical significance of BCG-induced granulomas in this patient population.

Main Methods:

• Eleven AML patients received repeated intravenous BCG injections (4-9 x 10^6 live organisms/mL).
• Bone marrow aspirates, liver, lung, spleen, lymph nodes, and skin biopsies were examined for granulomas.
• Serum alkaline phosphatase levels were monitored.
• Pre-treatment anergy status was assessed.

Main Results:

• Granulomas were found in the bone marrow of 8/11 patients.
• Granulomas were also observed in the liver (7/11), lung (3/11), spleen (1/11), lymph nodes (1/11), and skin (1/11).
• No clinical illness related to granulomas was observed, though one patient had elevated alkaline phosphatase.
• More extensive granuloma formation was noted in four patients who were likely anergic prior to treatment.

Conclusions:

• Intravenous BCG administration in AML patients can lead to widespread granuloma formation.
• Patients with pre-existing anergy may exhibit a more pronounced granulomatous response.
• Caution is advised when administering BCG intravenously, particularly to potentially immunoincompetent patients, until the full implications are understood.