Plasma C3c changes in myasthenia gravis patients receiving high-dose intravenous immunoglobulin during crisis

Beneficial effects of plasmapheresis before thymectomy on the outcome in myasthenia gravis

OBJECTIVE

Since 1980, we have performed plasmapheresis before thymectomy for patients with generalized symptoms in order to protect against myasthenic crisis and to improve patient outcomes after thymectomy. The aim of this study was to evaluate an immediate and a long-term results of plasmapheresis before thymectomy for myasthenia gravis, retrospectively.

METHODS

Between January 1980 and December 1997, 51 patients with Osserman class IIA or IIB symptoms were treated with transsternal thymectomy. Nineteen patients (group 1) were treated with plasmapheresis before thymectomy and 32 patients (group 2) were treated with thymectomy alone.

RESULTS

In group 1, the time of plasmapheresis prior to thymectomy was 3.2 +/- 1.5. Nine (28.1%) patients in group 2 had crisis within 1 year after thymectomy as compared with only one (5.3%) patient in group 1 had crisis (p = 0.049). There was no evidence of crisis within 30 days after thymectomy in group 1 and 5 (15.6%) patients in group 2 (p = 0.0724). There was no postoperative death among patients in group 1. Responses to thymectomy in group 1 improved significantly, the improvement and pharmacologic remission rate had increased up to 100% and 79% at 5-7 years after operation, while the improvement and pharmacologic remission rate of group 2 had increased to 81.3% (p = 0.0466 vs. group 1) and 50.0% at that time (p = 0.0427 vs. group 1).

CONCLUSIONS

The present study demonstrated that preoperative plasmapheresis may facilitate improved outcomes of patients with myasthenia gravis after thymectomy.

Effets immunomodulateurs des immunoglobulines intraveineuses

Intravenous immunoglobulins (IVIg) are therapeutic preparations of normal human IgG obtained from pools of more than 1000 healthy blood donors. They are currently used in the treatment of a wide range of auto-immune diseases, whether associated with auto-antibodies or auto-reactive T lymphocytes, as well as in the treatment of systemic inflammatory diseases. Several mechanisms of action have been identified during the last 20 years, including: (i) modulation of Fc receptors expression on leukocytes and endothelial cells; (ii) interaction with complement proteins; (iii) modulation of cytokines and chemokines synthesis and release; (iv) modulation of cell proliferation and apoptosis; (v) remyelinisation; (vi) neutralisation of circulating autoantibodies; (vii) selection of repertoires of B and T lymphocytes; (viii) interaction with other cell-surface molecules on lymphocytes and monocytes; (ix) corticosteroid sparing. These mechanisms of action are multiple and often intricate. However, they are still little known and further investigations are warranted.

Mechanisms of intravenous immunoglobulin action in the treatment of autoimmune disorders

Intravenous immunoglobulins (IVIg) are therapeutic preparations of normal human immunoglobulin (Ig) G obtained from pools of blood from more than 1000 healthy donors, and exert immunomodulatory effects in autoantibody-mediated and T-cell-mediated autoimmune disorders and systemic inflammatory diseases. IVIg mechanisms of action in autoimmune diseases have been extensively analysed during the last 15 years and include the following: (i) interaction of the IgG Fc fragment with Fc receptors on leucocytes and endothelial cells; (ii) interaction of infused IgG with complement proteins; (iii) monocyte and lymphocyte modulation of synthesis and release of cytokines and cytokine antagonists; (iv) modulation of cell proliferation and reparation; (v) neutralisation of circulating autoantibodies; (vi) selection of immune repertoires; and (vii) interaction with other cell-surface molecules on T and B lymphocytes.

Intravenous immunoglobulin treatment of neurological autoimmune diseases

Intravenous immunoglobulin (IVIg) has been widely used in neurological diseases during the last decade. The current indications of IVIg in neurological diseases are reviewed and discussed on the basis of the available experimental data and clinical trials. Compared to other immunomodulating treatments used in neurological diseases, IVIg has only few side effects with a small risk of transmission of infectious agents. Good clinical evidence for the effectiveness is available for Guillain-Barré-Syndrome, chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy. In conditions like myasthenia gravis and myositis favourable effects of IVIg were reported, but future studies have to be awaited. For all other neurological conditions where IVIg has been administered, there is currently no support for the use of IVIg other than in controlled trials. In conclusion, IVIg is a promising immunomodulary therapy that has been shown to be effective in some neurological autoimmune diseases. Routine use in neurological practice should be restricted to diseases for which a positive effect has been proven in controlled trials. For all other conditions no definite recommendations can presently be made.

The current place of high-dose immunoglobulins in the treatment of neuromuscular disorders

High-dose immunoglobulins for intravenous administration (IVIg) have originally been developed for substitution therapy in hypogammaglobulinemia. Over the last decade they are increasingly used in the treatment of immune-mediated diseases. In this review the results in immune-mediated neuromuscular diseases are summarized. Positive effects are demonstrated in open studies in dermato- and polymyositis, myasthenia gravis, and inflammatory neuropathies. Properly conducted randomized clinical trials demonstrating the effect of IVIg are available in dermatomyositis, Guillain-Barré syndrome, and chronic inflammatory demyelinating polyneuropathy, and smaller ones in multifocal motor neuropathy. In myasthenia gravis a trial is at present underway and only interim results are available. The results of a trial in the Lambert-Eaton myasthenic syndrome are in the process of publication. The therapeutic approach in individual patients is discussed, but often appears to be difficult. Considering chronic treatment with IVIg, proper long-term studies including cost-benefit studies are needed. Future developments aim for combination therapies, since IVIg and immune suppressants like prednisone are suggested to have a synergistic effect.

Treatment of myasthenia gravis with high-dose intravenous immunoglobulin

We treated 37 patients affected by autoimmune generalized myasthenia gravis (MG) with high-dose intravenous gammaglobulin (HDIVIg), 400 mg/kg per day on 5 consecutive days. A one-degree improvement of Oosterhuis global clinical classification of myasthenic severity (OGCCMS), the disappearance of bulbar involvement or both were recorded 12 days after the beginning of the treatment in 70.3% of the patients and persisted up to 60 days in 58.7%. A two-degree improvement of OGCCMS was recorded in 54.1% of the patients and it was maintained up to 60 days in 37.8%. The percentage of improvement did not significantly differ between patients entering the treatment in a long-standing, drug-refractory stationary phase of the illness (n = 26) and patients who received HDIVIg in an acute phase of MG (n = 11). None of the patients experienced side effects. Our data indicates that HDIVIg is an interesting, virtually riskless therapeutic choice for MG patients, and allows the planning of a controlled trial versus plasma-exchange.

Plasma C3c in immune-mediated neurological diseases: a preliminary report

Plasma C3c levels were examined in 56 patients with immune (27) and non-immune (29) mediated neurological diseases by crossed immunoelectrophoresis. Plasma samples were collected during the active phase of illness in both groups, usually within 7 days of admission. 11 patients (4 Guillain-Barré Syndrome-GBS, 3 chronic inflammatory demyelinating polyneuropathy-CIDP, 4 myasthenia gravis-MG) had their plasma saved sequentially during the active and the recovery phase. Plasma C3c levels were elevated in the group with immune mediated diseases when compared with those of non-immune mediated diseases. The sensitivity and specificity of C3c as a diagnostic test for immune mediated neurological diseases were 61.4 and 100% respectively with a positive and negative predictive value of 100 and 41%. the C3c levels in plasma correlated well with disease severity in MG and GBS patients. Such a correlation was also evident in all CIDP patients except one that had persistent elevation in the presence of clinical improvement. Results suggest that the plasma C3c level may be useful for differentiating immune from non-immune mediated neurological diseases. Plasma C3c may also be used for monitoring disease severity, particularly in myasthenia gravis.