Evaluation of an Innovative Colon Capsule Endoscopy Service in Scotland From the Perspective of Patients: Mixed Methods Study

BACKGROUND

Colonoscopy is the gold standard for lower gastrointestinal diagnostics. The procedure is invasive, and its demand is high, resulting in long waiting times. Colon capsule endoscopy (CCE) is a procedure that uses a video capsule to investigate the colon, meaning that it can be carried out in a person's own home. This type of "hospital-at-home" service could potentially reduce costs and waiting times, and increase patient satisfaction. Little is currently understood, however, about how CCE is actually experienced and accepted by patients.

OBJECTIVE

The aim of this study was to capture and report patient experiences of the CCE technology (the capsule and associated belt and recorder) and of the new clinical pathway for the CCE service being rolled out as part of routine service in Scotland.

METHODS

This was a mixed methods service evaluation of patient experiences of a real-world, deployed, managed service for CCE in Scotland. Two hundred and nine patients provided feedback via a survey about their experiences of the CCE service. Eighteen of these patients took part in a further telephone interview to capture more in-depth lived experiences to understand the barriers and opportunities for the further adoption and scaling up of the CCE service in a way that supports the patient experience and journey.

RESULTS

Patients overall perceived the CCE service to be of significant value (eg, mentioning reduced travel times, reduced waiting times, and freedom to complete the procedure at home as perceived benefits). Our findings also highlighted the importance of clear and accessible information (eg, what to expect and how to undertake the bowel preparation) and the need for managing expectations of patients (eg, being clear about when results will be received and what happens if a further colonoscopy is required).

CONCLUSIONS

The findings led to recommendations for future implementations of managed CCE services in National Health Service (NHS) Scotland that could also apply more widely (United Kingdom and beyond) and at a greater scale (with more patients in more contexts). These include promoting CCE with, for, and among clinical teams to ensure adoption and success; capturing and understanding reasons why patients do and do not opt for CCE; providing clear information in a variety of appropriate ways to patients (eg, around the importance of bowel preparation instructions); improving the bowel preparation (this is not specific to CCE alone); providing flexible options for issuing and returning the kit (eg, dropping off at a pharmacy); and embedding formative evaluation within the service itself (eg, capturing patient-reported experiences via surveys in the information pack when the equipment is returned).

ScotCap - A large observational cohort study

AIM

The aim of this work was to evaluate the performance of colon capsule endoscopy (CCE) in a lower gastrointestinal diagnostic care pathway.

METHOD

This large multicentre prospective clinical evaluation recruited symptomatic patients (patients requiring investigation of symptoms suggestive of colorectal pathology) and surveillance patients (patients due to undergo surveillance colonoscopy). Patients aged 18 years or over were invited to participate and undergo CCE by a secondary-care clinician if they met the referral criteria for a colonoscopy. The primary outcome was the test completion rate (visualization of the whole colon and rectum). We also measured the need for further tests after CCE.

RESULTS

A total of 733 patients were invited to take part in this evaluation, with 509 patients undergoing CCE. Of these, 316 were symptomatic patients and 193 were surveillance patients. Two hundred and twenty-eight of the 316 symptomatic patients (72%) and 137 of the 193 surveillance patients (71%) had a complete test. It was found that 118/316 (37%) of symptomatic patients required no further test following CCE, while 103/316 (33%) and 81/316 (26%) required a colonoscopy and flexible sigmoidoscopy, respectively. Fifty-three of the 193 surveillance patients (28%) required no further test following CCE, while 104/193 (54%) and 30/193 (16%) required a colonoscopy and flexible sigmoidoscopy, respectively. No patient in this evaluation was diagnosed with colorectal cancer. Two patients experienced serious adverse events - one capsule retention with obstruction and one hospital admission with dehydration due to the bowel preparation.

CONCLUSION

CCE is a safe, well-tolerated diagnostic test which can reduce the proportion of patients requiring colonoscopy, but the test completion rate needs to be improved to match that of lower gastrointestinal endoscopy.

Transfacial transpterygomaxillary access to foramen rotundum, sphenopalatine ganglion, and the maxillary nerve in the management of atypical facial pain

Post-traumatic atypical facial pain syndromes are refractory to medical therapy and thus challenging to treat. Some of these patients have a facial causalgia syndrome that may include autonomic as well as trigeminal fibers as the anatomic mediators. A procedure that may be of both diagnostic and therapeutic benefit is a nerve block in the region of the foramen rotundum. This allows access to both the maxillary nerve and the sphenopalatine ganglion. A simple technique developed to perform this procedure is described, and the results in a series of six patients are presented.

Healthcare for lesbians: attitudes and experiences

This article reviews the literature relating to healthcare provision for lesbians. The author discusses the attitudes of healthcare providers to this client group and the experiences of these women in a prejudiced healthcare system.

The sexual needs of elderly people: addressing the issue

The subject of sexuality and elderly people has until recently, largely been ignored by nurses. This article stresses the importance of acknowledging that sexual activity and interest changes with ageing and that to deny that it exists is detrimental to the holistic care nurses should aim to provide.

Importance of communication training for psychiatric residents and mental health trainees

Through the illustration of a clinical vignette and excerpts from interviews with trainees, this paper suggests that communication and communication disorders are essential issues in child psychiatry training. The vignette shows how communication issues pervade a multidisciplinary psychoeducational day treatment program. The importance of communication in the clinical experience and its impact on the professional preparation of psychiatry residents and mental health trainees are examined, and conclusions and recommendations for the goals of a training program in child psychiatry are presented which expand upon those findings.

Developmental brain anomalies in schizophrenia and bipolar disorder: a controlled MRI study

Many of the structural brain abnormalities found in schizophrenia (SC) and bipolar disorder (BD) over the past decade are believed to represent impaired neurodevelopmental processes. The authors hypothesized that incidental developmental anomalies would be more frequently present in the brains of subjects with SC and BD compared with healthy control subjects. The authors systematically assessed the MRI scans of 167 subjects (SC = 67, BD/schizoaffective = 63, healthy control subjects = 37) for the presence of 23 developmental anomalies involving cortical and subcortical structures. No excess neurodevelopmental anomalies were found in the schizophrenic or bipolar/schizoaffective groups. These findings do not support the hypothesis that SC and BD are associated with an excess of gross neurodevelopmental brain anomalies.

Peroxisomal beta-oxidation of branched chain fatty acids in human skin fibroblasts

Human skin fibroblasts in suspension are able to degrade [1-14C]-labeled alpha- and gamma-methyl branched chain fatty acids such as pristanic and homophytanic acid. Pristanic acid was converted to propionyl-CoA, whereas homophytanic acid was beta-oxidized to acetyl-CoA. Incubation of skin fibroblasts with [1-14C]-labeled fatty acids for longer periods produced radiolabeled carbon dioxide, presumably by further degradation of acetyl-CoA or propionyl-CoA generated by beta-oxidation. Under the same conditions similar products were produced from very long chain fatty acids, such as lignoceric acid. Inclusion of digitonin (> 10 micrograms/ml) in the incubations strongly inhibited carbon dioxide production but stimulated acetyl-CoA or propionyl-CoA production from fatty acids. ATP, Mg2+, coenzyme A, NAD+ and L-carnitine stimulated acetyl-CoA or propionyl-CoA production from [1-14C]-labeled fatty acids in skin fibroblast suspensions. Branched chain fatty acid beta-oxidation was reduced in peroxisome-deficient cells (Zellweger syndrome and infantile Refsum's disease) but they were beta-oxidized normally in cells from patients with X-linked adrenoleukodystrophy (ALD). Under the same conditions, lignoceric acid beta-oxidation was impaired in the above three peroxisomal disease states. These results provide evidence that branched chain fatty acid, as well as very long chain fatty acid, beta-oxidation occurs only in peroxisomes. As the defect in X-linked ALD is in a peroxisomal fatty acyl-CoA synthetase, which is believed to be specific for very long chain fatty acids, we postulate that different synthetases are involved in the activation of branched chain and very long chain fatty acids in peroxisomes.

Fulminant hepatic failure related to omeprazole

Omeprazole is a new hydrogen-potassium adenosine triphosphatase antagonist with indications for severe reflux esophagitis and Zollinger-Ellison syndrome. Side effects involving the liver have consisted of minimal elevations of hepatocellular enzymes with higher dosages. We present what we believe is the first reported case of fulminant hepatic failure related to omeprazole.

Magnetic resonance imaging of white matter lesions in HIV infection

Previous studies of the frequency of high-signal lesions in human immunodeficiency virus (HIV) infection have had methodological weaknesses regarding lack of control groups, differing machine strengths, and biased subject selection. To obtain a more accurate estimate of prevalence, MRI scans were performed on 243 HIV-positive and HIV-negative homosexual or bisexual men with no history of intravenous drug use. Axial T2-weighted (long TR/TE, spin-echo) MRI scans were rated blindly for presence of focal white matter high-signal lesions. Incidence of hyperintensities was low in all groups, although slightly higher in patients with AIDS, and was not associated with neuropsychological performance. The lower incidence of hyperintensities appears to relate to elimination of methodological problems in previous studies.

High-resolution 3DFT MR imaging of the endolymphatic duct and soft tissues of the otic capsule

This study compares the visualization of otic capsule anatomy by thin-section three-dimensional Fourier transformation (3DFT) MR imaging with that by high-resolution CT. The osseous margins of the otic capsule are delineated by high-resolution CT, while MR displays the soft-tissue structures. Routine two-dimensional Fourier transformation (2DFT) spin-echo MR techniques have been limited by slice thickness and signal to noise. Previous longer TE 3DFT gradient-echo MR images of the otic structures have been degraded by magnetic susceptibility effects, which limit spatial resolution and decrease signal to noise. These effects are especially prevalent in the otic capsule, where small soft-tissue structures interface with surrounding air and bone. We developed a high-resolution 3DFT MR technique to image five normal subjects. MR images were compared with high-resolution CT images of the same subjects. Axial, sagittal, and coronal 3DFT gradient-echo MR images with a short TR/TE and 15 degrees flip angle were acquired on a General Electric 1.5-T Signa unit using a 3-in. circular, receive-only surface coil. Axial, sagittal, and coronal 1.5-mm-thick contiguous high-resolution CT bone-algorithm images were obtained also. There was a high correlation between the MR and CT findings. The 3DFT MR images demonstrated significantly higher spatial resolution and soft-tissue detail than the high-resolution CT images did. For example, the endolymphatic duct was seen on twice the number of consecutive sagittal and axial MR slices. Other soft-tissue otic capsule structures routinely seen on the 3DFT MR images included the entire facial nerve, membranous labyrinth including cochlea, and tensor tympani muscle. This study demonstrates a new high-resolution 3DFT MR technique for visualizing the soft-tissue microstructures of the otic capsule and achieves a level of spatial resolution beyond that possible with high-resolution CT.

Normal venous anatomy of the brain: demonstration with gadopentetate dimeglumine in enhanced 3-D MR angiography

This investigation evaluates whether gadopentetate dimeglumine enhancement of three-dimensional (3-D) acquisition MR angiography can generate clinically useful images of the normal venous anatomy of the brain. 3-D MR angiography of normal cerebral arterial anatomy has made rapid progress, although demonstration of detailed venous anatomy with similar techniques has been much less revealing. To overcome the limitation of slow venous flow, IV gadopentetate dimeglumine contrast enhancement was used to alter the relaxation times of blood, thus augmenting the venous signal. Several groups of patients were evaluated: we studied eight patients both with and without contrast enhancement, 20 patients and volunteers with multiple techniques to determine optimal technical parameters, and seven patients in whom enhanced MR studies were compared with standard selective biplane cut-film arterial angiograms. Only the large dural sinuses (such as the transverse sinus) could be seen on unenhanced studies owing to the saturation of slowly flowing venous spins. With contrast enhancement, many of the important small and large cerebral venous structures were routinely seen with reasonable scanning times (7 min). The venous anatomy was well seen for approximately one-half hour after injection and correlated well with angiograms. There are several important limitations to this technique, including a limited field of view, variable visibility of specific veins owing to technical and physiologic factors, confusion of enhancing non-flow-related structures, and lack of detailed physiologic information. Single excitation 3-D MR angiograms are insensitive in the evaluation of cerebral venous structures. Enhancement with gadopentetate dimeglumine affords rapid scanning and excellent visualization of the pertinent venous anatomy. The best image quality was obtained with a sequence of 50/7/30 degrees (TR/TE/flip angle).

Hypothalamic interconnections of somatostatin and growth hormone releasing factor neurons

Combined immunohistochemical labelling for neurons containing growth hormone (GH) releasing factor (GRF) or somatostatin and single labelling immunohistochemistry combined with Fluorogold retrograde transport labelling were used to examine whether somatostatin or GRF neurons might be reciprocally innervated. Occasional somatostatin-immunoreactive neurons in the periventricular preoptic area were found to be closely approached by GRF-immunoreactive fibres, providing possible evidence of scant innervation of somatostatin neurons by GRF cells. In contrast, many GRF-immunoreactive neurons in the arcuate nucleus appeared to have somatostatin-immunoreactive fibres closely applied to their perikarya suggesting that GRF neurons might be innervated by somatostatin cells. Combined retrograde tracing and fluorescence immunohistochemistry revealed few somatostatin-immunoreactive neurons doubly labelled following injections of Fluorogold in the basal hypothalamus. Occasional GRF-immunoreactive neurons in the basal hypothalamus were doubly labelled following PO/AHA injections of Fluorogold. Numerous somatostatin-immunoractive perikarya were observed in the periventricular arcuate region in colchicine-pretreated animals. We conclude that GH-regulating neurons do not have strong reciprocal innervation. The innervation of GRF neurons by somatostatin fibres may be derived from local somatostatin neurons.

Intrahypothalamic actions of somatostatin and growth hormone releasing factor on growth hormone secretion

Possible effects of GRF on somatostatin neurons and of somatostatin on GRF neurons were examined by measuring the effects of localised intracerebral injections of these peptides on growth hormone (GH) secretion. Serial GH concentrations were measured in plasma in unanaesthetized male rats chronically prepared with venous and intracerebral cannulae, before and after treatment with bilateral intracerebral injections of somatostatin or GRF in the preoptic anterior hypothalamic area (PO/AHA) and medial basal hypothalamus. Injections of 0.1 and 1 nmol of GRF in medial basal hypothalamus or 10 nmol somatostatin in the PO/AHA, respectively, had stimulatory or inhibitory effects on GH, which were assumed to be due to diffusion of the peptide from the injection site to the median eminence and pituitary gland. Injection of lower doses of somatostatin around GRF neurons in the medial basal hypothalamus were without significant effect on secretion of GH, but 0.1 nmol somatostatin in the PO/AHA resulted in an increase in GH concentrations from 128 +/- 61 to 524 +/- 103 ng/ml, p less than 0.02. Injections of GRF in lower doses amongst somatostatin neurons in the PO/AH or amongst GRF neurons in the medial basal hypothalamus were both without effect on GH secretion. We conclude that somatostatin may stimulate GH secretion by an effect on or close to somatostatin neurons in the PO/AHA. Somatostatin, though present in terminals on GRF neurons, is without effect at this site in our model. Furthermore, we have been unable to demonstrate any significant intrahypothalamic effect of GRF on GH regulation.

Heart rate variability analysis in full-term infants: spectral indices for study of neonatal cardiorespiratory control

The heart rate and respirations of twenty healthy full-term infants between 30 and 60 h postnatal age were studied during quiet sleep with the objective of defining spectral indices which represent normal neonatal heart rate variability (HRV) characteristics. Total HRV power and the distribution of power across different frequency bands varied considerably among infants. Cluster analysis on the measured variables indicated that the population divided into two groups that represented significantly different patterns of HRV behavior. In one group (11 subjects), infants had lower breathing rates and HRV power in a band about the respiration frequency [respiratory sinus arrhythmia (RSA) band] was more than 20% of the total power (TP). Additionally, the ratio of low frequency band power to RSA band power was less than 4. The other group of neonates (nine subjects) had relatively higher breathing rates, RSA power less than 20% of total power, and low frequency to RSA power ratio greater than 4. Regression analysis of low frequency versus TP and RSA versus TP graphs gave strong support to the hypothesis that there were indeed two distinct patterns of HRV behavior. Separation of apparently normal neonates into two groups may be attributed partially to differences in respiratory rates and breathing patterns. However, it is possible that differences in the balance between sympathetic and parasympathetic nervous system control, perhaps related to autonomic maturation, also contribute to group separation. The indices developed from HRV spectral analysis in this investigation may be of value in the study of cardiorespiratory control in neonates.

Computed tomography and magnetic resonance imaging of the normal anatomy of the temporal bone

The high image quality provided by current high resolution CT bone algorithms in conjunction with the multiplanar and soft tissue imaging capabilities of MRI, provide exquisite anatomic detail of the temporal bone structures. This allows the radiologist to visually dissect this complex, three-dimensional structure, if a firm understanding of normal anatomy exists. In this way, the pathological processes involving the temporal bone can be better understood and correlated with the clinical setting.

Enhanced peripheral blood T-cell cytotoxicity in inflammatory bowel disease

Monoclonal antibodies to the CD3 component of the T-cell antigen receptor can trigger antigen-specific cytotoxic T cells to elicit nonantigen-specific cytotoxicity, possibly by mimicking or bypassing the requirement for antigen triggering. We have used this technique to investigate the possible presence of in vivo primed cytotoxic T cells, of unknown antigen specificity, in peripheral blood of patients with inflammatory bowel disease. Peripheral blood lymphocytes, which were depleted of background natural killer (NK) activity (CD16-), from patients with Crohn's disease exhibited significantly enhanced levels of anti-CD3-triggered T-cell cytotoxicity compared with lymphocytes from normal subjects. Enhanced lytic activity was also found in some patients with ulcerative colitis and in patients with ulcerative colitis postcolectomy. These results were not influenced by treatment or disease activity. There was no correlation between the anti-CD3-triggered T lytic activity and the NK activity in normal subjects or in patients with inflammatory bowel disease. The surface antigen phenotype of the anti-CD3-triggered T killer cell was CD3+, CD8+, CD16-, and Leu 7+. The results provide indirect evidence for increased activity of a subpopulation of cytotoxic T cells, of unknown antigen specificity, in inflammatory bowel disease. Increased activity in patients with ulcerative colitis postcolectomy suggests that this might reflect a fundamental immunological disturbance.

Hermansky-Pudlak syndrome: an immunologic assessment of 15 cases

PURPOSE

The Hermansky-Pudlak syndrome is an autosomal recessive disorder consisting of the triad of oculocutaneous albinism, a storage pool platelet defect, and multisystem tissue deposition of ceroid pigment. Although the underlying metabolic defect has not been identified, secondary or associated effects on the immune system are suggested by reports of an association with disorders such as pulmonary fibrosis, granulomatous colitis, lupus, and frequent bacterial infections. We evaluated a large group of patients with the Hermansky-Pudlak syndrome to assess immune competence in this condition.

PATIENTS AND METHODS

Fifteen patients with this syndrome were studied. Control subjects included healthy volunteers in the same age range as the patients. Peripheral blood lymphocytes and neutrophils were isolated according to previously described methods. Immunofluorescent staining, flow cytometry, and cytotoxicity assays were performed. Determination of lymphocyte transformation, mixed lymphocyte response, and neutrophil function was made.

RESULTS

Immunoglobulin levels, complement, lymphocyte subsets, natural killer and lymphokine-activated cytotoxicity, mixed lymphocyte responses, and lectin-induced transformation were normal in all patients. In addition, there was no evidence for a lymphocyte proliferative response to a preparation of urinary ceroid pigment isolated from these patients. Neutrophil function, including luminol-dependent chemiluminescence, chemotaxis, and aggregation was not significantly different from control values.

CONCLUSION

The results suggest that there is no generalized defect of peripheral blood lymphocyte or neutrophil function in the Hermansky-Pudlak syndrome. We propose that future studies should examine the possibility that associated disorders arise from a defect within the monocyte-macrophage system, perhaps secondary to ceroid accumulation.

Magnetic resonance imaging and clinical correlations in multiple sclerosis

We examined the relationship between magnetic resonance imaging (MRI) cerebral findings and clinical evaluations in 66 patients with clinically definite multiple sclerosis (MS). MRI observations included total number and location of lesions visualized, degree of periventricular involvement, degree of degeneration of the corpus callosum, and extent of generalized parenchymal atrophy. Overall physical disability was evaluated by the Kurtzke Expanded Disability Status Scale (EDSS) and individual symptoms were rated according to the Kurtzke Functional Systems (FS) scale. Our results suggest that MRI brain abnormalities are significantly related to the overall severity of disease, but MRI is not particularly useful to predict the presence or absence of individual symptoms. These findings do suggest that the MRI may provide useful information to monitor clinical progression of patients with MS, but the lesions visualized need not always be symptomatic nor are we sure that all symptomatic lesions, particularly in the spinal cord and optic nerves, will be visualized.

Human mucosal cytotoxic effector cells

Human intestinal lamina propria mononuclear cells have been shown to mediate mitogen-induced cellular cytotoxicity, antibody-dependent cellular cytotoxicity, and lymphokine activated killer cell function. However, although natural killer cells have been demonstrated in the gut mucosa of rodents, recent reports found little or no spontaneous cytotoxic activity in the lamina propria of the human gut. Using the natural killer cell-related monoclonal antibody NKH-1, which has not previously been applied to studies of mucosal killer cell function, we have shown by immunofluorescence that 2%-3% of enzymatically dispersed lamina propria lymphocytes are NKH-1+. A "panning" technique was then used to enrich for the NKH-1+ cells. Panned cells were consistently greater than or equal to 80% NKH-1+ by indirect immunofluorescence. Unlike their counterparts in the peripheral blood, the mucosal NKH-1+ cells were Leu-11-. Although unseparated lamina propria lymphocytes failed to exhibit natural killer activity against K562 targets in 4-h chromium release assays at effector to target ratios of up to 100:1, the NKH-1+ cells were cytolytically active at ratios of less than 5:1. Mucosal lymphocytes depleted of natural killer cells (NKH-1-) exhibited cytotoxic activity when cultured for 72 h with interleukin-2. The precursors of the lymphokine culture activated phenomenon were NKH-1-, Leu-11-, T4-, T3-, T11+, and T8+. Although lamina propria T3+ cells did not exhibit spontaneous or culture activated cytotoxicity, they were shown to exhibit nonspecific anti-CD3 (anti-T3)-induced T-cell cytotoxicity. In conclusion, functional natural killer and lymphokine activated killer cells are both present in the human gut mucosa and represent distinct populations of cytotoxic cells. In addition, anti-CD3-induced cytotoxicity is a feature of mucosal T cells. These mucosal killer cell subsets differ phenotypically from those previously described in the peripheral blood.

Modulation of ongoing human immunoglobulin synthesis by natural killer cells

Freshly separated human NK cells (NKH-1+) inhibited IgE synthesis from IgE myeloma U266/AF-10 as much as 70% whereas they enhanced IgG and IgA synthesis 200 and 500% from the lymphoblastoid cell lines GM-1500 and GM-1056, respectively. The inhibition of IgE synthesis by NK cells was due to a direct cytolytic effect on AF-10. This could be reversed using K562 cells in a cold target competition assay. NK cells also inhibited spontaneous IgE as well as IgG and IgA synthesis from B cells of highly atopic donors. On the other hand the enhancement of Ig secretion by NKH-1+ cells was shown to be mediated by soluble factors released from NK cells. Furthermore when NK cells were preincubated with immune complexes (IgE-IC) constructed of human IgE and mouse IgG1 monoclonal anti-human IgE, inhibition of IgE synthesis was reversed, and in some cases actual enhancement of IgE synthesis was observed, while enhancement of IgG and IgA synthesis was not affected. In contrast to NK cells, T cells depleted of NK cells (T-NK), when activated by IgE-IC, suppressed IgE synthesis in an isotype specific fashion. Thus, NK and T-cell modulation of ongoing Ig synthesis involve distinct mechanisms.

Evidence for involvement of serine proteases in the late stages of the natural killer cell lytic reaction

An irreversible inhibitor (L-1-tosylamide-2-phenylethyl-chloromethylketone) and substrate (N-acetyl-L-tyrosineethylester) of the neutral serine protease chymotrypsin were evaluated for their effects on the natural killer cell lytic reaction sequence. During direct cell-mediated cytolysis these inhibitors had no effect on natural killer cell binding to target cells but were able to inhibit the "trigger" mechanism which initiates killing. In addition, they inhibited later calcium-dependent events in the lytic reaction and killer cell-independent lysis. These findings suggest that serine proteases may be required during several stages of natural killer cell lysis, including calcium-dependent programming as well as the actual lethal hit.

Defective generation of tetanus-specific antibody-producing B cells after in vivo immunization of Crohn's disease and ulcerative colitis patients

In vivo booster immunization with tetanus toxoid normally results in the temporal development of circulating populations of B cells that secrete antibody after in vitro culture. In assessing the humoral immunoregulatory status in patients with inflammatory bowel disease, we found that the antibody production by the B cells that spontaneously secrete tetanus-specific immunoglobulin G in vitro, and which occur in the circulation 7 days postimmunization, was highly variable and below normal in the majority of Crohn's disease and ulcerative colitis patients. The decreased in vitro antibody responses correlated with the lack of an increase in the serum antitetanus immunoglobulin G titers, but did not correlate with disease activity, location, or steroid therapy. The majority of patients who did not produce an immunoglobulin G-antitetanus toxoid antibody response similarly failed to produce an immunoglobulin G-antidiphtheria antibody response after immunization. Lymphocytes from the patients who failed to produce normal levels of antitetanus toxoid antibody did, however, proliferate normally when stimulated by tetanus toxoid in vitro. These results suggest there are in vivo humoral immune defects in inflammatory bowel disease.

The effect of 6-mercaptopurine on natural killer-cell activities in Crohn's disease

Crohn's disease patients on long-term 6-mercaptopurine therapy (more than 4 months) were evaluated for activity of peripheral blood natural killer cells. Natural killer-cell cytolytic activity against K-562 tumor-cell targets was examined, as was natural killer-cell suppression of lymphoblastoid B-cell antibody production. In addition, these patients were studied for their ability to generate antitetanus-specific IgG-antibody-producing lymphoblastoid B cells following in vivo booster immunization. Crohn's disease patients on 6-mercaptopurine therapy had significant reductions in peripheral blood natural killer-cell activity against K-562 targets compared to normals, disease controls, and Crohn's disease patients not on 6-mercaptopurine. Natural killer-cell suppression of lymphoblastoid B-cell antibody production was likewise decreased in 6-mercaptopurine-treated patients compared to normal controls. In contrast, the in vivo generated lymphoblastoid B-cell antibody responses of Crohn's disease patients on 6-mercaptopurine therapy were not decreased compared to normal, while Crohn's disease patients not on 6-mercaptopurine therapy had significantly impaired IgG antitetanus antibody responses. These findings suggest that 6-mercaptopurine therapy in Crohn's disease affects several lymphoid subpopulations, resulting in a decreased natural killer-cell cytotoxic activity against K-562 target cells and a decreased natural killer-cell ability to suppress lymphoblastoid B-cell antibody production, as well as an improved humoral immune response following tetanus toxoid booster immunization.