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Myelosuppression in Legionnaires' disease
Abstract:
A patient undergoing examination for moderately severe renal insufficiency had fulminant five-lobed pneumonia caused by Legionella pneumophila. Her clinical course was complicated by granulocytopenia. Bone marrow aspiration showed notable inhibition of myelopoiesis, involving all stages of maturation. The presence of a serum inhibitor of granulopoiesis was demonstrated by in vitro bone marrow culture. Normal bone marrow cultured in the presence of serum from two normal control subjects yielded 69 +/- 5.2 (mean +/- SE) and 61 +/- 5 granulocyte colonies. When the patient's serum was substituted for normal human serum only 14.3 +/- 2.3 colonies were formed. Each of the drugs to which she had been exposed was tested in the in vitro system, using therapeutic concentrations, and none showed significant suppression of granulocyte colony formation. These observations indicate that legionnaires' disease was associated with a serum factor that notably inhibited the growth of granulocyte colonies in this patient.
Insights
Legionnaires' disease in a patient with renal insufficiency was linked to a serum factor inhibiting granulocyte colony growth. This inhibitor, not the patient's medications, caused granulocytopenia during severe pneumonia.
Area of Science:
- Infectious Diseases
- Hematology
- Immunology
Background:
- A patient with renal insufficiency developed severe pneumonia caused by Legionella pneumophila.
- The patient's condition was complicated by granulocytopenia, a significant decrease in granulocytes.
Observation:
- Bone marrow aspiration revealed marked inhibition of myelopoiesis across all maturation stages.
- In vitro bone marrow culture demonstrated a serum inhibitor of granulopoiesis.
Findings:
- Normal bone marrow cultured with patient serum produced significantly fewer granulocyte colonies (14.3 +/- 2.3) compared to normal serum (69 +/- 5.2 and 61 +/- 5).
- Therapeutic concentrations of the patient's medications did not suppress granulocyte colony formation in vitro, ruling them out as the cause.
Implications:
- Legionnaires' disease can be associated with a serum factor that inhibits granulocyte colony growth.
- This finding suggests a potential mechanism for the granulocytopenia observed in some severe Legionella infections.