Enumeration of lymphocyte populations defined by surface markers in the whole blood of patients with Crohn's disease

Treatment of Crohn's disease by lymphocyte apheresis: a randomized controlled trial. Groupe d'Etudes Thérapeutiques des Affections Inflammatoires Digestives

BACKGROUND/AIMS

Several uncontrolled trials suggest that lymphapheresis improves the clinical course of patients with Crohn's disease; this study was designed to assess the efficacy of lymphapheresis in preventing early relapses of Crohn's disease in patients in clinical remission after steroid treatment for an acute attack.

METHODS

Twenty-eight patients in clinical remission at the end of 3-7 weeks of steroid therapy were included in this randomized multicenter prospective trial. Before starting steroid tapering, patients were randomly assigned either to the lymphapheresis group (9 procedures within 4-5 weeks) or to the control group. The primary judgement criterion was the cumulated recurrence rate after steroid discontinuation.

RESULTS

All the patients treated by lymphapheresis (12 of 12) were successfully withdrawn from prednisolone and only 10 of 15 in the control group (NS). At the end of the 18-month follow-up period, the cumulated relapse rate was 83% in the lymphapheresis group and 62% in the control group.

CONCLUSIONS

Although there was a trend towards a diminished incidence of corticosteroid dependence, lymphapheresis did not prevent the occurrence of early relapses.

Flow cytometric analysis of peripheral blood lymphocytes in ulcerative colitis and Crohn's disease

Using two colour immunofluorescence with fluorescein isothiocyanate and phycoerythrin labelled monoclonal antibodies, multi-parameter flow cytometry was used to examine the antigenic characteristics of peripheral blood lymphocytes in whole blood of patients with ulcerative colitis and Crohn's disease who were not taking immunosuppressive drugs. The numbers of CD4+ and CD8+ lymphocytes in patients with ulcerative colitis and Crohn's disease remained unchanged so that the CD4/CD8 ratio was the same as that of normal control subjects. In Crohn's disease there were many activated T cells (CD3+, CD25+). Although natural killer cells in active Crohn's disease were lower than in normal control subjects, cytotoxic T lymphocytes, as defined by CD3+, CD16+, did not differ in patients with inflammatory bowel disease compared with normal control subjects. For B cell subsets, there were differences in Leu-1+ B cells, Leu-8+ B cells, Fc epsilon R+B cells (Leu-16+, Leu-20+), and activated B cells (Leu-12+, Leu-21+) between patients with inflammatory bowel disease and normal control subjects. These differences are compatible with local activation of B cells in the inflamed colon.

Elevated numbers of peripheral T cells in inflammatory bowel diseases displaying T9 antigen and Fc alpha receptors

Elevated numbers of peripheral T cells expressing the activation associated antigen T9 are found in patients with active Crohn's disease. Expression of T9 is found to be correlated to the activity of the disease. However the presence of activated peripheral T cells is not restricted to Crohn's disease, but could also be found in other maladies with a supposed involvement of the immune system, e.g. ulcerative colitis, sarcoidosis, connective tissue disease and after organ transplantation. Significant elevation of the number of activated T cells could not be detected in cases of viral or bacterial enteritis and coeliac disease. Analysing the subset of T9 positive T cells with regard to the expression of Fc alpha receptors, a significantly increased number of Fc alpha receptor positive cells, within the subset of T9 positive cells in the peripheral blood of patients with Crohn's disease and ulcerative colitis was found, which could not be demonstrated in the case of other diseases analysed in this study. Thus the T9+ Fc alpha receptor +T cell subset may be considered to be pathognomonic for inflammatory bowel diseases. Analysis of the regulatory properties of T9 positive cells, with regard to the immunoglobulin isotype secretion in a pokeweed mitogen stimulated autologeous B cell assay, suggests that peripheral T9 positive T cells are involved in the suppression of IgA synthesis or secretion.

Involvement of the immune system in the pathogenesis of Crohn's disease. Expression of the T9 antigen on peripheral immunocytes correlates with the severity of the disease

Peripheral lymphocyte cells from patients suffering from Crohn's disease were analyzed for the expression of the "activation" antigens T9 and HLA-DR on their cell surface. It was found that high numbers of "activated" lymphocytes, the majority of which have proven to be T cells, could be detected in patients with active Crohn's disease, whereas in healthy controls and inactive disease only a small subfraction of lymphocytes was positive for these antigens. This difference was highly significant (p = 0.0001). Within the subpopulation of T9-positive cells the ratio between T4- and T8-positive cells is about 1.8 (compared with 2.0 in the total T-cell subset). All HLA-DR-positive, non-B and non-glass-adherent cells could be detected in the T9-positive cell fraction. The presence of T9 antigens was found to correlate with the grade of severity of the disease as assessed by a Crohn's disease activity index. The presence of high amounts of T cells exhibiting this antigen is not restricted to Crohn's disease but is thought to be of importance as a marker for the involvement of the immune system in other maladies as well. Nevertheless, the determination of T9 antigen is expected to provide objective data reflecting the severity of Crohn's disease.

Loss of suppressor T-cells in active inflammatory bowel disease

The proportions and absolute numbers of helper and suppressor T-cells in 40 patients with inflammatory bowel disease and 22 control subjects were determined, using the monoclonal antibodies OKT 4 and OKT 8. There were no significant differences in helper or suppressor cell proportions among 15 steroid treated patients with active inflammatory bowel disease, 10 patients with inactive inflammatory bowel disease, 10 patients with other gastrointestinal diseases, or 12 normal control subjects. In contrast, 15 patients with active inflammatory bowel disease not treated with corticosteroids manifested increased proportions of helper cells and decreased proportions of suppressor cells (p less than 0.001), compared with all other patient groups and to normal controls. When absolute numbers of helper and suppressor subsets were measured, these alterations in proportions of helper and suppressor cells were primarily attributable to decreased counts of suppressor T-cells both in patients with active Crohn's disease and in those with ulcerative colitis (p less than 0.01). In four patients undergoing serial study, the helper/suppressor ratios appeared to rise and fall respectively with clinical exacerbations and remissions of disease. These data provide additional evidence for the involvement of cellular immune systems in these disease processes.