Mixed-lymphocyte reaction as a measure of immunological competence of lymphocytes from patients with Crohn's disease

Veiled cells in chronic idiopathic inflammatory bowel disease

The mononuclear cell system in the human gut wall of patients with Crohn's disease (CD), ulcerative colitis (UC) and normal controls was studied, with special reference to the so called antigen presenting veiled cells. These cells have already extensively been studied in the skin and are known as Langerhans' cells in the epidermis and dermis, veiled cells in the skin lymph and interdigitating cells in lymph nodes. Recently they were also found in gut associated lymphoid tissue, i.e. Peyer's patches of the rat. Here we describe the presence of similar cells in chronic idiopathic inflammatory bowel disease (CIBD). They resemble veiled cells in moving pattern, strong Ia positivity, no or only weak acid phosphatase activity, and ultrastructure. However, many of the described cells combine these characteristics with those of phagocytic macrophages. In the gut wall of controls veiled cells were virtually absent and phagocytic macrophages were almost exclusively recognized. These findings suggest that more intensive antigen handling takes place in the gut wall of CIBD patients than in normal gut. Clear cut associations with sex, age, duration or activity of disease were not observed in this limited study, and the exact significance of the presence of such cells needs further clarification.

A method for isolation and culture of lymphocytes from endoscopic biopsies

Human small and large intestinal lamina propria lymphocytes have been successfully prepared from endoscopic biopsies by a combined enzymatic and mechanical method which gives higher yields of viable mucosal lymphocytes than previously reported, despite the small size of the biopsy samples. Viability of the cells was demonstrated by dye exclusion and they could be satisfactorily maintained in short-term culture. Phytohaemagglutinin-P (PHA-P) transformation characteristics of intestinal lymphoid cells and those of peripheral blood were studied in 20 patients with Crohn's disease and 10 control subjects. Peripheral blood lymphocytes were separated according to this technique, no decrease in viability being observed when compared to a standard Ficoll-Hypaque gradient technique. Endoscopically abnormal (EA) and endoscopically normal (EN) Crohn's tissue showed significantly different responses to PHA-P (P less than 0.001), EA tissue lymphocytes giving lower blastogenic responses.

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

The proportions and absolute numbers of different lymphocyte populations were determined using alkaline phosphatase-labelled reagents in the whole peripheral blood of 22 patients with Crohn's disease. Monoclonal mouse anti-T cell antibody (OKT3) was used to identify T cells, polyvalent F(ab')2 anti-human immunoglobulin for B cells, C3b for C3b-receptor bearing cells, and soluble IgG antibody-antigen complexes for Fc(gamma)-receptor bearing cells. Endogenous myeloperoxidase served to distinguish monocytes. Application of this methodology to whole blood avoids the inevitable loss of cells which accompanies separation of mononuclear cells from blood and therefore permits precise enumeration of lymphocyte populations in the circulation. No significant difference from healthy adult controls was observed in any of the lymphocyte subsets tested.

Multiple immunologic pathogeneses for inflammatory diseases of the colon

There has been no clear indication, although there have been many indirect suggestions, that inflammatory diseases of the colon are due to immune activation against antigens of the colon. It is possible that inflammatory diseases of the colon have different etiologies and pathogeneses. Such etiologic differences may require different therapeutic approaches. The following paper will give experimental evidence which indicates that there are at least three different immunologic etiologies which can produce inflammatory colonic disease. This must be taken as a minimum number of etiologies and does not preclude the possibility that non-immunologic mechanisms may also produce these diseases.

Alteration in T lymphocyte subpopulations in inflammatory bowel disease

Peripheral blood mononuclear cells from thirty-one patients with inflammatory bowel disease (ulcerative colitis and Crohn's disease) were analysed for the proportions and absolute numbers of total T cells, and for the T cell subpopulations carrying Fc receptors for either IgM (Tmu cells) or IgG (T gamma cells). Twenty-six control subjects were studied simultaneously. Total T cell numbers were normal in patients with inflammatory bowel disease but there was a marked reduction in the proportion and absolute numbers of Tmu cells in patients, whether their disease was active or in remission. T gamma cells were normal. Simultaneous assessment of lymphocyte response to mitogens in vitro was performed in a group of patients. Responses to phytohaemagglutinin, concanavalin A and pokeweed mitogen were decreased and a positive correlation was found between the number of circulating Tmu cells and the responses to mitogens in vitro. These studies demonstrate that despite the presence of normal numbers of total T cells in inflammatory bowel disease, there is a marked imbalance in T cell subpopulations that correlates with mitogen responsiveness. This imbalance provides a possible cellular basis for the defect in cell-mediated immunity seen in these patients.

Animal model: immunologic model of inflammatory bowel disease

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Isolation and purification of human large bowel mucosal lymphoid cells: effect of separation technique on functional characteristics

Human large bowel lamina propria lymphoid cells have been isolated using both mechanical and enzymatic techniques. Their separation from other cell types after isolation was effected with greater efficiency by sedimentation on isokinetic gradients than by filtration through glass bead columns. After being purified, the capacity of the lamina propria lymphocytes to function in vitro as effector cells in antibody-dependent cellular cytotoxicity was determined. Mechanical distruption of the mucosa gave low yields of lymphoid cells, which lacked the capacity for cytotoxicity. Enzymatic digestion of mucosal tissue, by comparison, yielded large numbers of viable lymphoid cells which retained a significant level of cytotoxic activity. Investigation revealed that mechanical homogenisation stimulated the synthesis of prostaglandin E2, and inhibitor studies showed that this mediator was responsible for the lack of cytotoxic activity in mechanically-liberated lymphocytes.

[The immune competence of patients with Crohn's disease (author's transl)]

The cell-mediated and humoral immune responses were assessed in 15 patients with Crohn's disease and in 28 age-matched control subjects by means of several in vivo and in vitro methods. The disease activity in most patients was absent or moderate. Studying cellular immunocompetence we investigated the skin reactivity to various recall antigens (Candida, Trichophytin, Mumpsantigen, Streptokinase-Streptodornase, PPD), the primary immune response to Dinitrochlorobenzene (DNCB) and Keyhole Limpet Hemocyanin (KLH), and the lymphocyte transformation induced by mitogens (Phytohemagglutinin, Concanavaline A, Pokeweed Mitogen) and specific antigens. Humoral immunity was studied by measuring immunoglobulins, isohemagglutinins, and the antibody response to KLH. In addition, complement components and (in 10 patients) the proportions of T- and B-lymphocytes in the peripheral blood were evaluated. Cutaneous responsiveness to Candida, Mumps-antigen, SK-SD, and DNCB as well as the cellular immune response to KLH were impaired in patients with Crohn's disease (significance was reached for SK-SD, DNCB, and the mean area of induration). The lymphocyte transformation test with PHA, ConA, and PWM revealed normal results. For specific antigens (PPD, SK-SD, KLH) a good correlation could be demonstrated between delayed hypersensitivity and the in vitro lymphocyte responsiveness. Humoral immunity was not unequivocally impaired in Crohn's disease. Five patients with Crohn's disease proved constantly decreased total absolute lymphocyte counts in peripheral blood. The proportions of T- and B-lymphocytes and the complement-levels were corresponding to those in normal controls. No correlation was found between immunological and clinical parameters. In conclusion, patients with Crohn's disease exhibited a partial impairment of the cellular immune response, whereas humoral immunity was not affected. However, it remains to be elucidated whether this immune defect represents a basic pathogenetic factor in the onset of the disease.

Chasing Crohn's

The importance of Crohn's disease in oral pathology is briefly discussed. A series of experiments using immunofluorescent tracing techniques is described which culminates in the identification of a Crohn's-specific circulating antibody which reacts with autologous oral mucosa in vitro. It is suggested that this forms the basis of a diagnostic test.

Immune status in Crohn's disease. 2. Originally unimpaired primary cell mediated immunity in vitro

One-way mixed lymphocyte cultures (MLC) were performed with peripheral blood lymphocytes of 21 patients with Crohn's disease (CD) not receiving salizylazosulphapyridine, steroids or azathioprine, seven patients with inflammatory bowel disease other than CD and ulcerative colitis, and 46 age- and sex-matched normal control subjects. The group of CD patients consisted of 11 patients with newly diagnosed, short-standing and so far untreated CD (group CD 1) and 10 patients previously treated with drugs and with mostly long-standing CD (group CD 2). Results showed that the MLC responsiveness was similar in all Crohn's disease groups, normal subjects and diseased controls. While there was no correlation between MLC responsiveness and either disease activity or disease duration when compared singly, those CD 2 patients who had highly active and/or very long-standing disease did exhibit a depressed MLC responsiveness as compared with that of normal subjects (p less than 0.001), CD 1 patients who had both inactive and short-standing disease (P less than 0.05), and diseased controls (0.1 greater than or equal to P greater than 0.05). The stimulatory capacity did not differ significantly between the CD groups and normal subjects or diseased controls; the latter, however, stimulated poorly compared with normal subjects (P less than 0.05). In accordance, an inverse relationship between the magnitude of the stimulatory capacity and the disease activity was found in the CD patients as a whole. These data suggest that there is no depression of the in vitro primary cell mediated immune response as a predisposing factor for CD or as an early event associated with the pathogenesis of CD.

The effect of azathioprine on cell-mediated immunity (CMI) to Candida albicans in Crohn's disease

Using as antigen a suspension of Candida albicans, strain A, three tests of cell-mediated immune reactivity (delayed skin hypersensitivity, lymphocyte stimulation and leucocyte migration inhibition) were undertaken in patients with Crohn's disease to determine the effect of azathioprine given as the sole anti-inflammatory medication. No significant effect was demonstrable on 48 hr induration in the skin test. Uptake of thymidine by lymphocytes in vitro, whether spontaneous or antigenically induced, was greater during azathioprine treatment than before it. The assumption that this finding might be associated with clinical recovery was confirmed in antigen-stimulated cultures by the fact that, irrespective of treatment, patients who had been able to resume their normal occupations showed markedly higher reactivity than those who were still disabled (P<0·002). It was also found that azathioprine treatment in itself potentiated lymphocyte stimulation by C. albicans. The range of values for inhibition of leucocyte migration was the same in the treated and untreated groups, but certain individuals displayed a substantial change in reactivity when re-tested after institution or discontinuation of azathioprine treatment. Untreated patients with Crohn's disease did not differ from normal subjects in their cell-mediated reactivity to C. albicans. The increased rate of thymidine uptake by lymphocytes from patients receiving azathioprine is discussed in the light of recent hypotheses linking virus-induced malignancy with lymphoblastic transformation.

Analysis of the lympho-plasmacytic infiltrate in Crohn's disease with special reference to identification of lymphocyte-subpopulations

Lympho-plasmacytic infiltrates in cryostat sections (resected small intestine or colon specimens and rectal biopsies) from 29 patients with Crohn's disease (CD) were studied with the immunoperoxidase and immunofluorescence technique, by means of specific anti-human lymphocyte globulin (ALG) and specific anti-human T-lymphocyte globulin (ATG). Control specimens were obtained from 16 patients with ulcerative colitis (UC) and 12 subjects without inflammatory bowel disease. Characteristic transmural inflammatory infiltrates in CD consisted mainly of lymphocytes. A wide variation of the relative T-cell proportion was observed. However, in contrast with UC, abundant numbers of T-lymphocytes in CD were often detected, particularly in the deeper layers of the bowel wall. Furthermore, in serial sections immunoglobulin-containing plasma cells were counted, using specific anti-IgA, -IgM, and -IgG antisera. A significant reduction of the IgA/IgM plasma cell-ratio was found in CD in comparison with UC and controls. Our results indicate that in CD a chronic cellular immune reaction is going on within the diseases gut, involving increased numbers of lymphocytes and particularly T-cells. It remains to be established whether a deficient IgA barrier has to be considered of primary pathogenetic importance.

Immunological studies in patients with Crohn's disease

An investigation of immunological parameters was conducted in 38 patients with Crohn's disease. The immunological tests employed included skin tests with dinitrochlorobenzene and a battery of common skin test antigens, lymphocyte transformation with phytohaemagglutinin and pokeweed mitogen, serum immunoglobulins, and absolute lymphocyte counts. Crohn's disease patients were divided into two groups, those treated with immunosuppressive drugs and those not receiving immunosuppressive medications. The latter group was subdivided into patients with active and inactive disease. Immunosuppressed patients with Crohn's disease did not develop sensitivity to dinitrochlorobenzene and had mildly depressed skin test reactivity to common skin test procedures. Non-immunosuppressed patients with active Crohn's disease also reacted less frequently to common skin test antigens, but 16 of 17 such patients developed sensitivity to dinitrochlorobenzene. Lymphocyte transformation with phytohaemagglutinin and pokeweed mitogen was normal in all groups of patients with Crohn's disease. However, when suboptimal incubation periods were used with phytohaemagglutinin stimulation, there was a significant difference between Crohn's disease patients and controls. Serum immunoglobulin levels and absolute lymphocyte counts were normal in all Crohn's disease patients. We conclude that immunity in Crohn's disease is qualitatively normal.

Lymphocytotoxic antibody in inflammatory bowel disease. A family study

The prevalence of lymphocytotoxic antibody in inflammatory bowel disease is 40 per cent. Twenty-seven of 90 relatives of 23 probands with the disease (30 per cent) demonstrated lymphocytotoxic antibody, as contrasted with only three of 69 control family members (4 per cent) (P less than 0.0001). Decreased lymphocytotoxicity against lymphocytes from patients with inflammatory bowel disease as compared to normal donor lymphocytes previously demonstrated in the serum of probands was also observed in the serums from family members of the probands. Nineteen of the 48 household contacts of probands (40 per cent) were positive for antibody, whereas eight of 42 nonhousehold contacts (19 per cent) demonstrated it (P less than 0.05). Eight of 16 spouses (50 per cent) of probands showed antibody. The increased prevalence of lymphocytotoxic antibody in family members of probands and its occurrence mainly in household contacts (consanguineous and non-consanguineous) may indicate the exposure of probands and their family members to a common environmental agent.

Peripheral blood and intestinal lymphocyte sub-populations in Crohn's disease

Immunofluorescent technques were utilized to study the nature and distribution of cells forming the inflammatory infiltrate in Crohn's disease. Tissue from resected ileum (one patient) or colon (one patient) when compared with corresponding control tissues contained increased numbers of B and T lymphocytes. B-cells of IgG class predominated in the mucosal lamina propria, whereas T-cells were prominent in the deeper layers of inflamed bowel. Inflammatory cells bearing Fc receptors were also present in these tissues. Decreased peripheral blood T-cell numbers returned to normal after resection of the involved bowel in the two patients studied. Impaired cellular immunity in Crohn's disease may thus result from T-cell sequestration in or loss from involved segments of intestine.

Impaired anamnestic cellular immune response in patients with Crohn's disease

The cellular immune system was studied in patients with Crohn's disease (CD), not receiving corticosteroids, or azathioprine, by means of in vitro and in vivo methods. It was found, that the in vitro lymphocyte reactivity of 54 CD patients after stimulation with a cocktail of antigens (varidase, trichophyton, candida, mumps, and PPD) was significantly depressed when compared with the response of 20 simultaneously cultured healthy controls (p less than 0-001) or a group of 54 separately cultured healthy controls, matched for age and sex (p less than 0-001). The lymphocyte response of a control group of 18 patients with malnutrition or malabsorption without any evidence of inflammatory bowel disease, was higher than the response of an equal number of CD cases, although the difference failed to reach significance. Intradermally injection of the same five antigens, as used in the antigen cocktail, showed a failure to react to any antigen in 13 out of 48 CD patients, in comparison with three of 48 matched healthy controls (p less than 0-01). In both CD patients, as well as in healthy controls a significant correlation could be demonstrated between the number of positive skin tests, the area of skin induration, and the in vitro lymphocyte responsiveness after stimulation with the antigen cocktail. In the CD group no correlation was found between in vitro responsiveness and disease activity, as defined by a score of clinical and biochemical parameters. The depressed skin reactivity and the hyporesponsiveness in the lymphocyte transformation test after stimulation by an antigen cocktail suggest that depression of the anamnestic cellular immune response is a basic feature in patients with Crohn's disease.

Comparative mapping of the local distribution of immunoglobulin-containing cells in ulcerative colitis and Crohn's disease of the colon

The local response pattern of immunoglobulin-containing cells was compared in Crohn's disease and ulcerative colitis by paired immunohistochemistry on specimens of the large bowel wall. In the "Crohn mucosa" with persisting glands the total cell count was on the average raised more than three times compared with controls. The numbers of IgA, IgM and IgG immunocytes were increased 2.0, 4.8 and 28.6 times, respectively. Only 0-2 IgD- and IgE-containing cells were generally found per section. No consistent differences in the mucosal response pattern were revealed when Crohn's disease was compared with ulcerative colitis. The deeper layers of the bowel wall were in both diseases more or less densely infiltrated by immunocytes-IgG cells compromising about 80%. Immunoglobulin-containing cells in the muscularis propria and subserosa were characteristically found in Crohn's disease. There was no indication of a primary defect in the secretory immunoglobulin system which appeared to be normal in areas with intact glands. The pronounced local humoral immune response, particularly that involving IgG, might be of pathogenetic importance by aggravating and perpetuating in the inflammatory bowel disease.

Leukocyte migration test in Crohn's disease, ulcerative colitis, and ankylosing spondylitis using Crohn's colon homogenate, mitochondrial, and microsomal fractions

Leukocytes from 33 patients with Crohn's disease, 20 patients with ulcerative colitis, and 20 patients with ankylosing spondylitis were tested for evidence of abnormal migration in the presence of preparations of colon from a patient with Crohn's disease. None of the patients was on treatment with immunosuppressive drugs. The test was also performed with leucocytes from 12 health subjects. Significant alteration was seen in the Crohn's disease group, particularly when the antigen used was mitochondrial or microsomal fraction of colon mucosa, whereas the patients in the ulcerative colitis group showed reactivity only with the whole colon homogenate and not with the subcellular fractions. The ankylosing spondylitis group showed no statistical difference from the normal controls with any of the antigens.

The distribution of mucosal antibodies in the bowel of patients with Crohn's disease

Specimens of intestine from 24 patients with histologically proven Crohn's disease have been studies by an immunofluorescent technique for the distribution of immunoglobulins A, G, M, E, and D. A marked reduction of IgA in lymphoid and epithelial cells was noted in those areas of the bowel which, although histologically affected, were not ulcerated; in the histologically unaffected areas of the bowel the distribution of IgA was similar to that found in control sections of normal bowel. There was an increase in IG7 in the affected areas but the numbers of lymphoid cells staining for IgD did not differ from those found in normal controls; in 12 cases of Crohn's disease, however, IgG appeared to be present in bound form on the surface of, and in, the epithelial cells. It is postulated that the local deficiency in IgA in the affected areas may be secondary to a local cell-mediated immune reaction, to a focal metaplasia of the surface epithelium, or to patchy bindings of anticolon antibodies to the surface epithelium. The effect of this local deficiency of IgA will be to allow for an increased focal entry of antigenic material into the bowel wall, and it is suggested that many of the pathological features of Crohn's disease are explicable on the basis of deep penetration of a variety of antigens.