Plasmapheresis in severe asthma

Atopy, autonomic function and beta-adrenergic receptor autoantibodies

Atopic individuals (with asthma, allergic rhinitis or atopic eczema) have impaired sensitivity to beta-adrenergic agents. After the finding of antibodies to the beta-adrenergic receptor in the serum of a subject with allergic rhinitis, coded sera from atopic and control subjects were assayed for immunoglobulins that inhibited the specific binding of 125I-labelled hydroxybenzylpindolol to beta-receptors in mammalian lung membranes. Antibodies were present in nine of 60 subjects: 3/19 normal control subjects, 1/9 pre-allergic, 4/17 asthma, 0/8 allergic rhinitis, and 1/7 cystic fibrosis patients. Antibodies of the IgG class in these sera were also demonstrated by indirect precipitation of solubilized lung beta-receptors. The autonomic sensitivity of the nine antibody-positive subjects (Ab+) was compared with that of antibody-negative subjects (Ab-). The Ab+ subjects required 15.0 +/- 1.9 ng isoprenaline (isoproterenol) kg-1 min-1 i.v. to increase pulse pressure by at least 22 mmHg (Ab-, 7.7 +/- 0.4; n = 20; P less than 0.001), and 12.4 +/- 1.8 ng isoprenaline kg-1 min-1 i.v. to increase plasma cyclic AMP concentrations by 50% (Ab-, 8.08 +/- 0.62; n = 13; P less than 0.02). Ab+ subjects required 2.06 +/- 0.3% phenylephrine to dilate their pupils (Ab-, 2.55 +/- 0.08; n = 57; P less than 0.05) and 0.61 +/- 0.08% carbachol to constrict their pupils (Ab-, 0.78 +/- 0.03%; n = 57; P less than 0.05). A role for autoantibodies as beta-receptor antagonists was further supported by showing that human lung cells (VA-13 line) cultured in the presence of globulins from Ab+ subjects had a markedly impaired cyclic AMP response to isoprenaline. These results suggest that autoantibodies to beta-receptors play a pathogenetic role in asthma and related disorders. They have important implications for the concept of autoimmunity.

Plasmapheresis in the treatment of steroid-dependent bronchial asthma

BACKGROUND

Can plasmapheresis improve disease severity and lung function and reduce steroid doses in severe asthma patients dependent on oral corticosteroids?

METHODS

A pilot study with four asthma patients was undertaken using PEF (peak expiratory flow) symptom score, number of puffs of beta2-agonist, and dose of systemic steroids as disease variables. After at least an 8-week run-in, the patients were randomized to a crossover treatment regimen consisting of either 10 days of plasmapheresis or placebo treatment. Each treatment was succeeded by an 8-26-week follow-up period.

RESULTS

No patients achieved a significant effect of plasmapheresis treatment according to the established criteria, nor did anyone experience deterioration.

CONCLUSIONS

Removing humoral factors extensively over a 10-day period did not significantly influence the clinical condition of the four steroid-dependent asthma patients studied. Circulating humoral factors seem to be of little importance for the maintenance of the established chronic allergic inflammation in these patients. Plasmapheresis does not seem to be a treatment option for this patient category.

Plasmapheresis in a patient with severe asthma associated with auto-antibodies to platelets

Although the pathogenesis of aspirin-sensitive asthma remains to be specified, it is known that in the presence of acetylsalicylic acid or non-steroidal anti-inflammatory drugs, platelets from aspirin-sensitive asthmatics have been described as generating cytocidal mediators that killed parasite targets such as Schistosoma mansoni larvae. Here we report, in a patient with corticosteroid-dependent asthma associated with aspirin sensitivity, the presence of circulating IgE antibodies against 55 kD and 68 kD platelet antigens. In addition, the serum from this patient was shown to contain a factor able to trigger the release of cytocidal mediators from his platelets as well as from normal individual platelets. This platelet stimulatory activity was presumably supported by IgE antibodies or immune complexes. After informed consent the patient was submitted to plasma exchanges. Plasma removal induced clinical improvement, anti-platelet antibody decrease, and the reduction of the platelet stimulatory activity. All clinical symptoms disappeared within 2 weeks. The disease remained quiescent for 2 months, and daily requirements for prednisone (20-5 mg), and beta-agonist (10-16 to 0-1 inhalations) could be kept at a low level follow-up. The plasma exchanges were delayed by 3 mg kg-1 azathioprine with the maintenance of clinical improvement. A relapse occurred after the arrest of immunosuppressive therapy with the reappearance of both asthma attacks and anti-platelet antibodies, as well as the increase of the platelet stimulatory activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Specific removal of IgE by therapeutic immunoadsorption system

A therapeutic immunoadsorption system was developed that can remove IgE effectively and specifically from the plasma of patients with an allergy or other hyper-IgE syndrome. The immunoadsorbent (IA) consists of immunoaffinity purified anti-IgE antibody (a-IgE ab) immobilized on controlled pore glass beads (50 nm pore size). Adsorption isotherms for IgE, which were reduced by the Freundlich adsorption equation, were obtained with IA that immobilized various amounts of a-IgE ab. An optimum amount of a-IgE ab to be immobilized was selected. IA worked sufficiently in a wide range of IgE concentrations. Clinical treatment requires an amount of 41 mg of IgE to be removed from a patient's plasma for 3 h. An IA for clinical use was designed to contain 10 g of the support binding 325 mg or more of the antibody. In fact, our study in vitro simulating a clinical case showed that serum IgE was removed by IA, as expected: the level decreased from 11,000 to 3000 U/ml after a 3 h perfusion (1 U = 2.3 ng). A very small amount of a-IgE ab (goat IgG) was found to be detached from IA by flowing plasma; the average level was 20 ng/ml, which seems to be safe. However, we installed the second column in a circuit that adsorbs a-IgE ab leaked into plasma, because the amounts of a-IgE ab infused into the patient must be minimized. The second column contained IgE immobilized on the same support, since IgE as a ligand adsorbed more a-IgE ab than did anti-goat IgG antibody. This is an effective and safe therapeutic immunoadsorption system and has been subjected to clinical tests.

Plasma separation in patients with bronchial asthma, atopic dermatitis and hyperimmunoglobulinaemia E

The effect of intensive plasma separation performed eight times within 5 weeks in four patients with atopic dermatitis, bronchial asthma and hyperimmunoglobulinaemia E was followed as regards clinical symptoms and changes in the concentrations of serum (S) IgE, S IgG, S IgA, S IgM, plasma complement C3 split products, S transferrin, blood eosinophils, chemotaxis of neutrophil cells and histamine metabolites in urine in samples obtained consecutively during the period of observation. The occurrence of circulating immune complexes (IC) was analysed by a polyclonal rheumatoid factor (pRF) agglutination inhibition assay and an IgE IC specific technique. IgE IC were demonstrated in three of the patients prior to plasma separation, complexed IgE was 2-3% of the total concentration of S IgE. In one patient complexes were detected by the pRF agglutination inhibition assay, also. In the three patients with IgE IC, the complexes disappeared during treatment, but recurred in two of the patients shortly after the last plasma separation. Shortly after eight separations the S IgE was reduced in all patients to a mean level of 46% of the pre-exchange concentrations. During the following 3 weeks the relative increase of S IgE in three of the patients was similar to the values obtained for S IgG. Serum IgG was subnormal in all patients during the period of treatment. Increasing numbers of eosinophils were observed in three of the patients after the fifth separation procedure. The histamine metabolite 1,4-methylimidazoleacetic (1,4- MIAA ) in urine was increased in all patients, but no significant changes were observed during the treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Therapeutic apheresis. Applications and future directions

The past 10-15 years have been witness to major technological achievements in the field of therapeutic apheresis. Concurrently, a large number of diseases, primarily with an immunological basis, have been treated with apheresis. In this paper, we review the various applications of therapeutic apheresis, adverse reactions associated with the mode of therapy, and future research directions. Several representative diseases are also discussed in detail.

Plasma exchange: a selective form of blood-letting

The technique of, and indications for, plasma exchange are presented. This selective form of plasma removal has re-established "blood-letting" in medical therapeutics on a scientific basis. It is the most appropriate therapy when hyperviscosity or haemostatic failure complicate immunoproliferative disease. Plasma exchange is also a significant advance in the management of fulminant forms of autoimmune disease, but in many other conditions it must be regarded as experimental.