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Monocyte and granulocyte defect in chronic lymphocytic leukemia
Insights
Chronic lymphocytic leukemia (CLL) patients show deficiencies in key enzymes like beta-glucuronidase, myeloperoxidase, and lysozyme across multiple white blood cell types. Enzyme levels normalize in remission, suggesting linked cell differentiation in leukemia.
Area of Science:
- Hematology
- Biochemistry
- Oncology
Background:
- Chronic lymphocytic leukemia (CLL) is a hematological malignancy characterized by the accumulation of abnormal lymphocytes.
- Understanding the underlying cellular and enzymatic abnormalities in CLL is crucial for developing targeted therapies.
Purpose of the Study:
- To investigate the enzymatic profiles of different leukocyte populations in patients with chronic lymphocytic leukemia (CLL).
- To compare enzyme levels in CLL patients with healthy individuals and with CLL patients in remission.
Main Methods:
- Isolation of enzymatically homogeneous populations of lymphocytes, monocytes, and neutrophils using zonal centrifugation.
- Quantitative analysis of six leukocytic enzymes in isolated cells from untreated CLL patients, in-remission CLL patients, and normal subjects.
Main Results:
- CLL monocytes exhibited deficiencies in beta-glucuronidase, myeloperoxidase, and lysozyme compared to normal controls.
- CLL neutrophils showed severe deficiencies in lysozyme and myeloperoxidase in some cases.
- CLL lymphocytes shared beta-glucuronidase deficiency with monocytes.
- Leukocyte enzyme levels normalized in CLL patients who achieved full remission.
- CLL lymphocytes from untreated patients were unresponsive to mitogens but responsive in remission; monocytes transformed into macrophages.
Conclusions:
- The shared enzyme deficiencies among lymphocytes, monocytes, and neutrophils in CLL suggest an enzymatically interlinked differentiation process.
- Aberrant differentiation of leukemic cells may underlie the observed enzyme deficiencies in CLL.
- Normalization of enzyme levels in remission indicates a potential link between differentiation and disease status.
Abstract:
Enzymatically homogeneous populations of lymphocytes, monocytes, and neutrophils were isolated by zonal centrifugation from 5 untreated patients with chronic lymphocytic leukemia (CLL) and 2 patients with CLL in full remission. The cells were then quantitatively analyzed for six leukocytic enzymes and compared with cells from normal subjects. CLL monocytes were deficient in beta-glucuronidase (0.06 units; normal, 0.16), myeloperoxidase (0.07 mg; normal, 0.5 mg), and lysozyme (0.7 mg; normal, 3.3 mg). In 2 cases, CLL neutrophils were severely deficient in lysozyme (1 to 2 mg; normal, 7 mg) and myeloperoxidase (2 to 3 mg; normal, 7 mg). Neutrophil alkaline phosphatase and neutral protease were unaffected. CLL lymphocytes shared with the monocytes the deficiency of beta-glucuronidase (0.03 units; normal, 0.09 units). The 2 CLL patients in full remission carried normal enzyme levels in leukocytes of all three cell lines. The CLL lymphocytes of untreated patients were unresponsive to mitogens but became responsive in remission. The CLL monocytes from both untreated and treated patients transformed into macrophages. The pattern of shared enzyme deficiency among lymphocytes, monocytes, and neutrophils of CLL patients and its normalization in all three cell types under remission suggest that the differentiation of the three leukocytic cell lines may be an enzymatically interlinked process and that the deficiency of these enzymes in leukemia may reflect an interrelated aberrant differentiation of the leukemic cells.