Thirty-five patients with autoimmune diseases who were on long-term immunoadsorption therapy participated in a prospective, randomized study. Results and conclusions. Infections were rare but similar in frequency in patients receiving combined immunoadsorption and intravenous immunoglobulins (intervention group, n=17, 1.3 infections per patient-year) and in a control group (n=18, 0.9 infections per patient-year) treated by immunoadsorption alone. The reduction in IgG achieved with two immunoadsorptions within 3 days was 95.0+/-2.5%. The extent of removal of pathogenic autoantibodies was similar to the removal of IGG: Substitution of immunoglobulins was not associated with an increased circulating IgG level before the following immunoadsorption. Infusion of immunoglobulins at a dose of 0.14 g/kg (interquartile range 0.12-0.16) body weight in patients in whom circulating immunoglobulins had been depleted was associated with a high incidence of serious side-effects; these necessitated the termination of treatment in 24% of the patients. No evidence was found that immunoglobulin administration had any beneficial effect with respect to autoantibody resynthesis after immunoadsorption.

Acute treatment of myasthenic crisis with immunoadsorption (IA) or plasma exchange is well established. The efficiency of chronic apheresis therapy in myasthenia gravis (MG), however, and its efficacy in reducing concomitant potentially harmful immunosuppressive therapy, is unknown. We treated 13 patients with therapy-resistant MG or severe steroid or azathioprine therapy-related side effects, or both, with long-term IA [median, 38 (range: 16-59) months]. IA was performed every second day until partial remission was achieved (modified Osserman score <2). Subsequently, oral immunosuppressive therapy was reduced and the frequency of IA adapted to the clinical symptoms. After initiation of IA the mean (SEM) Osserman score decreased from 3.23 +/- 0.12 to 1.23 +/- 0.08 within 1 month (P < 0.01). Mean azathioprine dose was reduced concomitantly from 89 +/- 9.4 mg/day to 56 +/- 11 mg/day (P < 0.05), and mean prednisolone dose from 41 +/- 7.6 mg/day to 22 +/- 8.5 mg/day (P < 0.05). After 36 months the number of IA-sessions/month had been reduced from 4.81 +/- 0.24 to 2.64 +/- 0.4 (P < 0.05), the mean azathioprine dose to 25 +/- 17 mg/day and the mean prednisolone dose to 9 +/- 3.6 mg/day. Six out of thirteen patients were weaned from IA after a median of 33 (range, 16-50) months and a decrease of the Osserman score to 0.33 +/- 0.33. In these patients MG remained stable during a follow-up period of 28 (range, 16-38) months. We conclude that long-term IA enables the reduction of oral immunosuppressants in patients with contraindications or resistance to steroid and azathioprine therapy. Furthermore, almost 50% of the patients can be weaned from IA with then substantial lower need of further immunosuppressive therapy.

In previous experimental animal studies it has been demonstrated that antibody depletion is not followed by increased antibody synthesis. To assess whether these results are conferrable to antibody-depleted humans, we measured free light chains (flcs) as markers of current antibody synthesis in 8 patients treated with immunoadsorption (IA) therapy. Specific and bulk immunoglobulin levels were obtained simultaneously. The mean serum flc concentration increased to the preapheresis value within 1 day and remained unchanged thereafter. Total immunoglobulin G (IgG) and specific antibody concentrations increased to pretreatment values in 88% and 43% of the patients, respectively, and remained below the original values in the others. In conclusion, the lack of increased flc synthesis after IA confirms the absence of a feedback mechanism regulating antibody synthesis. IntroductionThe regulation of serum antibody levels has been a subject of debate for several decades. A large number of studies have provided evidence for enhanced antibody synthesis after immunoglobulin depletion and thus for the existence of an immunoregulatory feedback mechanism. [1][2][3][4][5][6][7] In contrast, Charlton and colleagues 8-10 demonstrated with a series of animal experiments that the rapid increase of antibody serum levels after plasmapheresis could be explained by immunoglobulin backflow from extravascular space and decreased catabolism alone. More than 10 years later the lack of an increased antibody synthesis in a low immunoglobulin state was confirmed in the excellent studies by Junghans and Anderson 11 and by Junghans. 12 Knock-out mice with disrupted immunoglobulin G (IgG) protection receptors, which effect increased catabolism of IgG and subsequently low IgG serum levels, had a similar biosynthesis rate as normal control subjects.The complex metabolism of IgG has so far prevented exact measurement of immunoglobulin synthesis in humans with low antibody levels. However, a prerequisite for immunoglobulin assembly is the synthesis of free light chains (flcs) that are produced in excess during antibody production and secreted as free or monomers into the vascular space. 13,14 Because flcs have a half-live of only 2 to 4 hours, 15 they reflect current immunoglobulin production and can be used for estimating the activity of diseases accompanied by autoantibody synthesis. 16,17 We hypothesized that increased antibody synthesis after immunoglobulin depletion would be accompanied by increased flc serum levels and measured free and light chain concentrations in 8 patients undergoing immunoadsorption (IA) therapy. Study designThe study protocol was approved by the local ethics committee, and the patients' informed consent was obtained. Eight patients with various autoimmune diseases and normal kidney function treated with IA therapy were recruited (Table 1). Concomitant immunosuppressive therapy was prednisolone (n ϭ 4), mycophenolate mofetil (n ϭ 3), and cyclosporine A (n ϭ 1); 3 patients received no additional therapy. We recruited additi...

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