Alpha interferon treatment in myasthenia gravis: effects on natural killer cell activity

Association of polycythemia vera with positive JAK2V617F mutation and myasthenia gravis: A report of two cases

Screening for MG in patients with PV positive for JAK2V617F mutation can help in early diagnosis and treatment, resulting in a significant reduction in morbidity and mortality.

How I Manage Natural Killer Cell Deficiency

Natural killer (NK) cell deficiency (NKD) is a subset of primary immunodeficiency disorders (PID) in which an abnormality of NK cells represents a major immunological defect resulting in the patient’s clinical immunodeficiency. This is distinct from a much larger group of PIDs that include an NK cell abnormality as a minor component of the immunodeficiency. Patients with NKD most frequently have atypical consequences of herpesviral infections. There are now 6 genes that have been ascribed to causing NKD, some exclusively and others that also cause other known immunodeficiencies. This list has grown in recent years and as such the mechanistic and molecular clarity around what defines an NKD is an emerging and important field of research. Continued increased clarity will allow for more rational approaches to the patients themselves from a therapeutic standpoint. Having evaluated numerous individuals for NKD, I share my perspective on approaching the diagnosis and managing these patients.

Reciprocal regulation between natural killer cells and autoreactive T cells

The initiation and the progression of autoimmune diseases stem from complex interactions that involve cells of both the innate and the adaptive immune system. As we discuss here, natural killer (NK) cells, which are components of the innate immune system, can inhibit or promote the activation of autoreactive T cells during the initiation of autoimmunity. After they have been activated, autoreactive T cells contribute to the homeostatic contraction of NK-cell populations. The dynamic interaction between NK cells and autoreactive T cells might indicate the transition from the innate immune triggering of autoimmunity to the progressive phase of the disease. Understanding the mechanisms and signals that control the reciprocal regulation of NK cells and autoreactive T cells could have important implications for treatment in the clinic.

Lymphocyte subsets, TNFα and interleukin-4 levels in treated and untreated subacute sclerosing panencephalitis patients

Immunologic studies in relation to clinical status might help to understand the pathogenesis of subacute sclerosing panencephalitis (SSPE) and the effect of treatment. We measured lymphocyte subsets and intracellular TNFalpha and interleukin-4 levels in peripheral blood in SSPE patients. Patients had elevated percentages of CD8+ cells compared to age-matched control children. Rapidly progressive course was associated with increased CD4+ cells. Treatment with interferons and inosiplex altered the percentage of CD3+, CD4+ and CD19+ cells. TNFalpha and interleukin-4 levels had no correlation with course or treatment. The proportions of lymphocyte subsets appear to have a role in the evolution or manifestations of SSPE, if not in the pathogenesis.

Defect of a subpopulation of natural killer immune cells in Graves' disease and Hashimoto's thyroiditis: normalizing effect of dehydroepiandrosterone sulfate

BACKGROUND

The study of the natural killer (NK) immune compartment could provide important findings to help in the understanding of some of the pathogenetic mechanisms related to autoimmune thyroid diseases (Graves' disease (GD) and Hashimoto's thyroiditis (HT)). Within this context, it was suggested that alterations in NK cell cytotoxicity (NKCC) and NK production of cytokines might occur in subjects with GD and HT, whereas the normalization of NK functions could potentially contribute to the prevention of the onset or the progression of both diseases.

OBJECTIVE

Due to the hypothesis of alterations in NK in autoimmune thyroid diseases, we were interested to evaluate NKCC in GD and HT patients and to modulate NK function and secretory activity with cytokines and dehydroepiandrosterone sulfate (DHEAS) in an attempt to normalize NK cell defect.

DESIGN

We studied 13 patients with recent onset Graves' disease, 11 patients with Hashimoto's thyroiditis at first diagnosis and 15 age-matched healthy subjects.

METHODS

NK cells were concentrated at a density of 7.75x10(6) cells/ml by negative immunomagnetic cell separation and validated by FACScan as CD16+/CD56+cells. NK cells were incubated with interleukin-2 (IL-2) and interferon-beta (IFN-beta) and co-incubated with DHEAS at different molar concentrations for measuring NKCC and the secretory pattern of tumor necrosis factor-alpha (TNF-alpha) from NK cells.

RESULTS

Lower spontaneous, IL-2- and IFN-beta-modulated NKCC was demonstrated in GD and HT patients compared with healthy subjects (P<0.001). A decrease in spontaneous and IL-2-modulated TNF-alpha release from NK cells was also found in both groups of patients (P<0.001). The co-incubation of NK cells with IL-2/IFN-beta+DHEAS at different molar concentrations (from 10(-8) to 10(-5) M/ml/NK cells) promptly normalized NKCC and TNF-alpha secretion in GD and HT patients.

CONCLUSIONS

A functional defect of a subpopulation of NK immune cells, involving both NKCC and the secretory activity, was demonstrated in newly-diagnosed GD and HT patients. This defect can be reversed by a dose-dependent treatment with DHEAS. The impairment of NK cell activity in autoimmune thyroid diseases could potentially determine a critical expansion of T/B-cell immune compartments leading to the generation of autoantibodies and to the pathogenesis of thyroid autoimmunity.

[Interferon-alpha and auto-immunity]

PURPOSE

To assess the role of endogenous interferon alpha (IFN) in auto-immune experimental models and human diseases, and to evaluate its iatrogenic potential as a therapeutic agent.

MAIN POINTS

IFN is a cytokine involved in cellular immunity, that promotes both differentiation of dendritic cells and the TH1 pathway. Auto-immune side-effects of recombinant IFN depend on IFN dosage and the pathology concerned. The spectrum extends from occurrence of auto-antibodies in an asymptomatic patient to overt disease such as systemic lupus. Antigenic targets of auto-antibodies are diverse: blood cells coagulation factors, immunoglobulin, hormones, intrinsic factor, intracellular components. Thyroiditis is the most frequently reported auto-immune disease occurring during IFN treatment, including hypothyroidism, hyperthyroidism or a bi-phasic pattern. Currently, true incidence of thyroiditis remains debated. It appears very low (under 1%) in hepatologic series using low-dose IFN. The fact that auto-immunity may be related to the treated disease--before use of IFN--must also be addressed: e.g. antinuclear factors and anti-DNA antibodies in chronic myeloid leukemia or anti-actin and anti-LKM antibodies in chronic C hepatitis.

FUTURE PROSPECTS

Recombinant alpha interferon appears more as a trigger than a de novo inducer of auto-immune disorders. Its use as an immunomodulator agent should be treated with caution.

Myasthenia gravis during low-dose IFN-alpha therapy for chronic hepatitis C

We describe the case of a 56-year-old man who had high aminotransferase levels and anti-hepatitis C virus (HCV) antibodies. He underwent liver biopsy and biochemical screening to evaluate whether he would benefit from interferon (IFN) treatment. The patient was discharged with a diagnosis of HCV-related active chronic hepatitis, skin porphyria, and type 2 diabetes. On December 5, 1995, he began therapy with recombinant IFN-alpha at a dose of 3 MIU three times a week. He stopped this therapy in February 1996 because of asthenia, diplopia, headache, and anxiety. During IFN therapy, he had normal aminotransferase levels and no detectable HCV RNA, a condition that persists to the present. Between March and May 1996, the patient was admitted several times to a neurology clinic, where myasthenia gravis was diagnosed and treatment with pyridostigmine and cyclosporine was initiated. This case and others indicate that caution should be exercised in administering IFN because low doses can be correlated with myasthenia gravis in patients without malignancies.