Influence of azathioprine (imuran) on in vitro immune function in multiple sclerosis

Treatment of Acquired Autoimmune Myasthenia Gravis: a Topic Review

We propose a new approach to staging the disease based on clinical and immunological response to treatment. We oppose clinical remission to immunological remission and define total clinical remission as the goal of therapy. We describe the use, side effects and indications of established therapies. Acetycholine esterase inhibitors are only a symptomatic treatment as is plasma exchange. Usefulness and limits of thymectomy, corticosteroids and immunosuppressants are described here. Their goal is to reduce the auto-immune process. Long-term hazards from these medications are described and methods to reduce their potential risks are suggested. We suggest the number of patients having life threatening complications while undergoing aggressive immunosuppression can be reduced by a systematic approach to follow-up. In the second part of this review article, adapting management to specific situations is emphasized in refractory disease, respiratory failure, neonatal and juvenile forms of the disease. The special situation of seronegative myasthenia is discussed.

What is left when anti-tumour necrosis factor therapy in inflammatory bowel diseases fails?

The inflammatory bowel diseases (IBDs) are chronic incurable conditions that primarily present in young patients. Being incurable, the IBDs may be part of the patient’s life for many years and these conditions require therapies that will be effective over the long-term. Surgery in Crohn’s disease does not cure the disease with endoscopic recurrent in up to 70% of patients 1 year post resection. This means that, the patient will require many years of medications and the goal of the treating physician is to induce and maintain long-term remission without side effects. The development of the anti-tumour necrosis factor alpha (TNFα) agents has been a magnificent clinical advance in IBD, but they are not always effective, with loss of response overtime and, at times, discontinuation is required secondary to side effects. So what options are available if of the anti-TNFα agents can no longer be used? This review aims to provide other options for the physician, to remind them of the older established medications like azathioprine/6-mercaptopurine and methotrexate, the less established medications like mycophenolate mofetil and tacrolimus as well as newer therapeutic options like the anti-integins, which block the trafficking of leukocytes into the intestinal mucosa. The location of the intestinal inflammation must also be considered, as topical therapeutic agents may also be worthwhile to consider in the long-term management of the more challenging IBD patient. The more options that are available the more likely the patient will be able to have tailored therapy to treat their disease and a better long-term outcome.

Activation of humoral immunity and eosinophils in neuromyelitis optica

OBJECTIVE

To study immunologic alterations in patients with neuromyelitis optica (NMO).

METHODS

The authors studied 8 patients with NMO together with 16 healthy subjects, 16 patients with relapsing remitting multiple sclerosis (RRMS), and 16 patients with secondary progressive MS (SPMS), matched for age and sex, as controls. Because recent histopathologic studies have demonstrated that active NMO lesions consist of perivascular immunoglobulin (Ig) deposition and eosinophil infiltration, IL-5, IL-6, IL-12, IgG, and IgM production by anti-myelin oligodendrocyte glycoprotein (MOG) mononuclear cells in peripheral blood and CSF were selected for study using ELISPOT. Eotaxin-2 (Eo-2) and eotaxin-3 (Eo-3) levels were also assessed using ELISA and eosinophil cationic protein (ECP) levels by radioimmunoassay.

RESULTS

MOG-specific responses in CSF showed significant increase in IL-5, IL-6, IgG, and IgM secreting cells in NMO patients compared with patients with RRMS, SPMS and healthy subjects. Interestingly, numbers of IgM secreting cells were significantly higher than identical specificity IgG secreting ones. Moreover, CSF Eo-2, Eo-3, and ECP levels were also significantly higher in NMO patients compared to all three control populations. Anti-MOG IL-12 secreting cells were increased in CSF and peripheral blood from NMO, RRMS, and SPMS patients when compared to healthy subjects.

CONCLUSIONS

These observations suggest that neuromyelitis optica is associated with a major humoral immune response (particularly anti-MOG IgM production) and eosinophil activation present exclusively in CSF.

The Second Canadian Conference on Multiple Sclerosis

The epidemiology of multiple sclerosis (MS) and the planning and i interpretation of clinical therapeutic trials were the subjects of a symposium on MS held on June 13, 1989. Several speakers addressed whether MS is a genetic or an environmental disease. An environmental trigger would resolve the relatively low penetrance of the disease in susceptible individuals, although the alternative hypothesis that MS is a multigenic disease would also account for this observation. Clinical trials have to date failed to confirm the efficacy of any immunosuppressive or other agent in the management of progressive MS. Magnetic resonance imaging (MRI) appears to be highly sensitive for monitoring the activity of MS. Preliminary evidence suggests that MRI activity correlates with longitudinal clinical assessments of disability. Immunologic tests, while valuable in determining pathophysiology of MS, have not been strongly correlated with clinical outcome.

Multiple sclerosis: an overview

Demyelinating lesions of MS are infiltrated by activated T-lymphocytes and macrophages with secretion of soluble factors. This results in the synthesis of oligoclonal immunoglobulin (IgG) by plasma cells. The activated T-lymphocytes migrate from the peripheral blood to the CNS. This hyperactive state is linked to a selective loss of the suppressor/inducer T-cell subset. Administration of a soluble factor--interferon gamma--enhances the immune response by promoting class II antigen expression on macrophages or astrocytes, resulting in a relapse. However, the reason for T-cell activation in peripheral blood is not known, nor is the antigen. Myelin basic protein (MBP) has been considered to be the target since MBP is able to induce chronic relapsing allergic encephalomyelitis (CRAE) in an animal model of MS. Yet other myelin antigens have succeeded in inducing CRAE in animal models, and anti-MBP antibodies have been found in healthy individuals. The possibility that the hyperimmune state results from a viral infection has not yet been proven. It is known that in Caucasians, a genetic susceptibility factor is linked to class II MHC. Using MRI it has been found that the presence of new plaques was not regularly correlated with relapses, which indicates that MS is an ongoing pathology process. Most drugs used in MS influence the immune response but have potential toxicity. Monoclonal antibodies offer the opportunity of specific targeting of T-cells and are promising for the future.

Peripheral blood lymphocyte phenotype and function in multiple sclerosis

T suppressor cell function and phenotype are abnormal in patients with multiple sclerosis, especially during the chronic progressive phase but the sub-populations defined by mitogen stimulation and serological methods may not be identical. In this study, involving 45 patients with multiple sclerosis and 33 controls, there was no correlation between T suppressor function and CD8 cell phenotype in patients with multiple sclerosis or in controls. These phenotypic and functional studies cannot therefore be used interchangeably in the assessment of patients with multiple sclerosis since they provide different information about lymphocyte subpopulations.

Loss of functional suppression is linked to decreases in circulating suppressor inducer (CD4+ 2H4+) T cells in multiple sclerosis

A consistent immunological finding in patients with progressive multiple sclerosis is a loss of functional suppression. We have recently found decreases in suppressor inducer T cells in progressive multiple sclerosis as measured by two-color immunofluorescence using differentiation markers CD4 and 2H4. In the present study, we examined the relationship between functional suppression and circulating CD4+ 2H4+ T cells using a two-stage assay. (1) T cells were stimulated for 7 days with irradiated non-T cells (autologous mixed lymphocyte reaction [AMLR]) and harvested. It has previously been shown that suppressor T cells are generated during the course of the AMLR. (2) The AMLR-generated suppressor T cells were then incubated with mononuclear cells plus pokeweed mitogen, and immunoglobulin (Ig) synthesis was measured. There was less AMLR-induced suppression of IgG synthesis in patients with progressive multiple sclerosis as compared with normal subjects and patients with other neurological diseases. More importantly, there were significant correlations between decreases in circulating CD4+ 2H4+ cells and the AMLR (p = 0.009). Thus, the decreases in functional suppression and the decreases in the AMLR in multiple sclerosis appear tightly linked to CD4+ 2H4+ cells, and their measurement provides a means to monitor suppressor function phenotypically. Decreases in suppressor inducer T cells may in part explain immunoregulatory abnormalities observed in multiple sclerosis.

Immunotherapy of multiple sclerosis

Based on the assumption that multiple sclerosis is an autoimmune disease, a number of clinical trials designed to suppress the immune system or to restore immune balance in multiple sclerosis have been attempted. Depending on the disease category, the clinical goals of immunotherapy differ. Therapeutic goals include improving recovery from acute attacks, preventing or decreasing the number of relapses, and halting the disease in its progressive stage. The ultimate goal of multiple sclerosis therapy is the early treatment of patients in an attempt to halt the onset of progression. Specific strategies of immunotherapy include generation of a suppressor influence, removal of helper/inducer cells, manipulation of activated T cells, manipulation of class II major histocompatibility complex-bearing cells, alteration of lymphocyte traffic, extracorporeal removal of serum factors or cells, and manipulation of antigen-specific cells. Present treatment modalities are beginning to show some efficacy of nonspecific immunosuppression, but these treatments are limited by their toxicities. As the immunotherapy of multiple sclerosis moves to the next stage in the coming years, patients at an earlier stage of their disease will have to be treated, nontoxic forms of therapy developed, clinical trials lengthened, and a laboratory monitor of the disease developed. Given the positive effects of immunotherapy seen thus far in the disease, it is possible that appropriate immunotherapeutic intervention may provide effective treatment for the disease in the future.

Double blind controlled randomized study on azathioprine efficacy in multiple sclerosis. Preliminary results

The preliminary results of a double blind controlled prospective randomized trial of Azathioprine for therapeutic efficacy in 38 patients with Multiple Sclerosis are reported. Progression of the disease is significantly reduced in Azathioprine-treated group in comparison to Placebo-treated patients, but this effect is reached only after 3 years of treatment (P less than 0.025) regardless of the clinical course and without affecting relapse rate.

A double-blind controlled trial of high dose methylprednisolone in patients with multiple sclerosis: 2. Laboratory results

Laboratory measurements were compared in paired samples from 50 patients included in a double-blind placebo controlled trial of methylprednisolone in the treatment of multiple sclerosis. Cerebrospinal fluid total cell count, IgG and C9 indices, and percentage of peripheral blood OKT8 positive cells were abnormal at entry and returned closer to the normal range after active than placebo treatment, but the differences were not statistically significant. The percentage of peripheral blood OKT4 positive cells was normal at entry as was the amplitude of visual evoked potentials, whereas their latency was prolonged; these measurements were each uninfluenced by methylprednisolone. Corticosteroids might act merely by influencing oedema, but the laboratory results suggest that methylprednisolone affects immunological events which underly rapid onset and recovery of symptoms in patients with multiple sclerosis; additional forms of treatment are needed to maintain these clinical and immunological effects.

Azathioprine reduces intrathecal IgG synthesis in multiple sclerosis

Intrathecal IgG synthesis and CSF oligoclonal bands were reexamined after 18-24 months in 66 patients with multiple sclerosis; 40 of them received azathioprine (AZA) 2.5 mg/Kg/die; all received a course of dexamethasone (DEXA) during clinical relapses. The IgG Index was significantly reduced in the group treated with AZA, especially in patients with short disease duration, low disability and high IgG index. Changes observed in CSF banding pattern were not significant. These results suggest an effect of AZA on IgG synthesis, as reported by in vitro studies.

Suppressor and cytolytic cell function in multiple sclerosis. Effects of cyclosporine A and interleukin 2

Patients with progressive multiple sclerosis (MS) demonstrated persistent reductions in levels of concanavalin A (Con A)-induced suppressor activity and heightened levels of in vitro pokeweed mitogen (PWM)-induced IgG secretion. The reduced Con A suppressor activity could not be reversed by addition of interleukin 2 (IL-2). Cyclosporine A (CsA) treatment did not alter the defect in Con A-induced suppressor activity, but did markedly inhibit T8+ cell-mediated alloantigen directed cytolytic activity; this latter defect was reversible by in vitro addition of IL-2. CsA-treated patients did not differ from placebo-treated patients with regard to levels of PWM-induced IgG secretion or proliferative responses of their mononuclear cells to Con A. The results indicate that CsA treatment of MS patients reduces cytolytic function from baseline normal values, but does not alter aberrant suppressor cell function.

Progressive multiple sclerosis: abnormal immune functions in vitro and aberrant correlation with enumeration of lymphocyte subpopulations

In a series of 27 consecutive progressive multiple sclerosis (MS) patients under age 50 we have simultaneously measured 3 in vitro immune functions and 6 markers and compared their results to a group of 21 controls. We have confirmed a reduction of concanavalin A (Con A) -induced suppression and NK function contrasting with increased IgG secretion in response to pokeweed mitogen (PWM). Among 6 monoclonal antibody-recognized subpopulation (Leu 1, Leu 2, OKT8, Leu 3, Leu 7 and Leu 11) only Leu 2+ lymphocytes were statistically reduced. OKT8+ were slightly reduced, Leu 3+ were slightly increased. Discriminant analysis revealed that the 3 immune functions together with the results of OKT8 and Leu 3 enumeration were sufficient to appropriately classify most of the individuals. Only 3 MS and 4 controls were misclassified. Correlation analysis suggested disappearance of the doubly labelled OKT8/Leu 7 population in MS patients. In MS as opposed to controls Con A-induced suppression did not correlate with suppressor cell markers but correlated with NK cell markers suggesting that in MS this population mediates Con A-induced suppression. IgG secretion and Con A suppressor cell function were inversely correlated in MS patients but not in controls, suggesting that in chronic progressive multiple sclerosis a common abnormality underlies both increased response to PWM and decreased induction of suppression by Con A.

Azathioprine and steroids are not more effective in decreasing multiple sclerosis intra-blood-brain-barrier IgG synthesis than steroids alone

Intra-blood-brain-barrier IgG synthesis rates and oligoclonal IgG banding patterns were examined in 9 patients with multiple sclerosis who were treated with azathioprine and steroids for 2 to 4.5 years. The IgG synthesis rates of 5 patients were significantly decreased from the pretreatment mean values 1 month after treatment, and their synthesis rates remained at the decreased levels throughout treatment. However, among the remaining 4 patients, the rates exceeded the pretreatment means. This continuous suppressive effect of the combined azathioprine and steroids upon the IgG synthesis rate was similar to that of steroids, suggesting that azathioprine and steroids in combination were not more effective in reducing intra-blood-brain-barrier IgG synthesis than steroids alone. Oligoclonal IgG patterns in all cerebrospinal fluid samples were not significantly altered during the study.

Analysis of T regulator cell surface markers and functional properties in multiple sclerosis

The relative proportions as well as cell surface and functional properties of T suppressor (T8+) and T helper (T4+) cells in peripheral blood mononuclear cells ( MNCs ) of MS patients were analyzed. The proportion of T8 cells compared to normal controls was suggestively lower in patients during relapses and significantly lower in those with progressive disease. The density of T8+ antigen on cells of MS patients with active disease as measured by median fluorescence intensity ( MFI ) was also decreased compared to controls and stable MS patients. Using OKT8-mAb modulated MNCs as a model, we found that reduction of T8 antigen density results in substantial discrepancies between FACS and microscope methods for enumeration of T8+ cells. Levels of pokeweed mitogen-induced IgG secretion by MNCs of MS patients did not correlate with proportion of T8+ cells within the MNCs , but rather with the functional activity of the T8+ cells of given individuals, as tested in an in vitro suppressor assay using constant numbers of T8+ cells.

A serial study of peripheral blood T lymphocyte subsets in relapsing-remitting multiple sclerosis

Twelve patients with relapsing-remitting multiple sclerosis and 3 control subjects were evaluated weekly for six months. Peripheral blood lymphocyte subsets were enumerated using monoclonal antibodies and analysis with a dual-laser fluorescence-activated cell sorter. Results were correlated with clinically assessed disease activity. Fluctuations occurred in the number of T lymphocytes (Leu 1+) and cells with the helper/inducer phenotype (Leu 3a/OKT4+) in both patients and controls. Fluctuations in the number of cells with the suppressor/cytotoxic (Ts/c) cell phenotype (OKT5, OKT8, Leu 2a+) also occurred. Variations in the relative numbers of cells labeled with all three Ts/c monoclonals did occur, but with OKT5 generally labeling fewer cells than OKT8 or anti-Leu 2a. When findings were correlated with disease activity, OKT5 was a more sensitive gauge of disease activity than either OKT8 or anti-Leu 2a. When peripheral blood lymphocyte subsets were correlated with disease activity, the following patterns were observed: a reduction in the number of Ts/c cells without evidence of clinical disease (four episodes), the development of new symptoms suggestive of an acute relapse but without a reduction in the number of Ts/c cells (two episodes), and a reduction in the number of Ts/c cells associated with acute relapse (two episodes). In the two patients with acute relapse and a reduction in the number of Ts/c cells, clinical disease preceded a reduction in the number of Ts/c cells in 1 patient, whereas the two events occurred simultaneously in the other patient. Taken together, these limited results indicate that in some cases a reduction in the number of Ts/c cells may be the result rather than the cause of disease activity and may represent an epiphenomenon.

The influence of disease activity on the number of blood cells of multiple sclerosis patients

The influence of disease activity on blood cell counts was studied in over 100 multiple sclerosis patients examined at regular intervals of 4-8 weeks over an 18-month period. T-lymphocytes were assessed by the cytochemical alpha-naphthyl-acetate-esterase (ANAE) stain in addition to conventional differentials. In all patients as a group as well as in individual patients studied sequentially, an exacerbation was marked by a striking reduction in both the relative and absolute numbers of ANAE-positive cells. Simultaneously, a strong increase in granulocytes and a slight augmentation of ANAE-negative cells occurred. Similar changes related to disease activity in leucocytes and lymphocytes were also detected in conventional blood smears. Fluctuations in the number of blood cells with disease activity persisted under therapy with corticosteroids and to a lesser degree also with azathioprine.

Mechanisms responsible for reduced in vitro immunoglobulin secretion in aged humans

Age-related changes in the processes involved in T cell dependent polyclonal B cell activation in man were studied by comparing immunoglobulin (Ig) produced in autologous T:B (E+:E-) cell cultures of young and old donor pairs with Ig produced in crossover cultures. Each young and old donor was classified as a responder or a non-responder based on Ig levels in autologous pokeweed mitogen-activated T:B cultures. The data indicate that: (1) T suppressor influences are a major determinant of non-response in the young; (2) T cells of nonresponder old donors can support high levels of Ig secretion by young donors' B cells; (3) low response to pokeweed mitogen stimulation in the elderly may reflect either direct refractoriness of B cells to T cell dependent stimulation, heightened B cell sensitivity to suppressor signals, or a combination of the two.

Comparative neurovirulence of herpes simplex virus type 1 strains after peripheral or intracerebral inoculation of BALB/c mice

Twenty-three strains of herpes simplex virus type 1 were compared for their pathogenicity in 4-week-old BALB/c mice after peripheral (footpad) or intracerebral inoculation. Among those strains examined were (i) six clinical isolates of brain or cerebrospinal fluid origin, (ii) seven clinical isolates of oral or genital origin, (iii) five prototype laboratory strains that have been passaged numerous times in culture, and (iv) five syncytial variants capable of producing cell fusion in culture. Based on comparative 50% lethal dose values, the strains appeared to segregate into one of three classes of neurovirulence. Class I strains were highly virulent by both the peripheral and intracerebral routes of inoculation, class II strains were highly virulent by the intracerebral route only, and class III strains were highly attenuated by both routes of inoculation. In vivo growth curves for whole brain homogenates infected with class III strains revealed titers of infectious virus approaching those found in the brains of animals infected with class I or II strains. These results would therefore suggest that (i) a strain-dependent variation in neural spread exists that may influence the ability of the virus to cause acute neurological disease and (ii) the amount of infectious virus present within an infected brain does not necessarily determine or reflect the clinical status of the animal. Of the clinical isolates examined, the strains recovered from brain tissue of humans after fatal episodes of encephalitis were found to be no more neurovirulent in mice than the strains isolated from nonneural sites. However, although syncytial variants were found to be highly attenuated by the peripheral route, as a group these strains proved to be among the most virulent when inoculated directly into the central nervous system.