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Immune status in Crohn's disease. I. Leukocyte and lymphocyte subpopulations in peripheral blood
Insights
In Crohn's disease (CD), circulating T-cells are not initially reduced but decrease with disease progression. B-cell proportions increase, suggesting immune dysregulation in CD patients.
Area of Science:
- Immunology
- Gastroenterology
- Hematology
Background:
- Crohn's disease (CD) is a chronic inflammatory bowel disease.
- Understanding circulating immune cell dynamics is crucial for CD pathogenesis.
- Leukocyte and lymphocyte subpopulations may be altered in CD.
Purpose of the Study:
- To investigate circulating leukocyte and lymphocyte subpopulations in CD patients.
- To compare immune cell profiles in newly diagnosed versus long-standing CD.
- To correlate immune cell numbers with disease activity and duration.
Main Methods:
- Flow cytometry was used to quantify leukocyte and lymphocyte subpopulations.
- 33 CD patients (newly diagnosed and previously treated) were studied.
- Comparison was made with age- and sex-matched healthy controls.
Main Results:
- CD patients exhibited leukocytosis with increased neutrophils and monocytes.
- Newly diagnosed CD patients (CD 1) had near-normal T-cell counts.
- Long-standing CD patients (CD 2) showed significantly reduced T-cells and lymphocytes.
- B-cell proportions were elevated in all CD groups; absolute B-cells increased in overall CD.
- Inverse correlation found between T-cell numbers and disease activity/duration in CD 1.
Conclusions:
- Reduced T-cell numbers in CD circulation appear to be a consequence, not a cause, of the disease.
- Immune cell alterations, particularly T-cell reduction, develop over time in Crohn's disease.
- Elevated B-cells may play a role in the immunopathology of CD.
Abstract:
Proportions and absolute numbers of circulating leukocyte populations and lymphocyte subpopulations (T- and B-cells) were determined in 33 patients with Crohn's disease (group CD), and were compared with those of age- and sex-matched healthy subjects. Group CD comprised 15 patients with newly diagnosed, short-standing, and untreated CD (group CD 1) and 18 patients with long-standing, previously drug treated CD (group CD 2). All CD groups showed a significant absoulte leukocytosis, based on a significant absolute and relative increase of the neutrophils, and, as far as group CD and CD 1 were concerned, also of the absolute number of monocytes. In group CD 1, absolute lymphocyte and relative as well as absolute T-cell numbers were close to normal. In contrast, in group CD 2 absolute as well as relative numbers of lymphocytes and absolute numbers of T-cells were highly significantly reduced, whereas the reduction of the relative T-cell concentration barely reached significance. The proportion of B-cells was significantly above normal in all patient groups, the absolute number in group CD only. Also group CD 1 showed considerably, though statistically insignificantly, higher than normal absolute B-cell numbers. In group CD 1 , there was an inverse correlation between absolute T-cell numbers and disease activity, and between absolute lymphocyte numbers and duration of disease. These data indicate that there is no gross numerical reduction of the carriers of the cell-mediated immunity as a primary predisposing factor for CD, but that a reduction of these cells occurs in the circulation after the disease has started.