Beta-2-microglobulin (beta 2m) plasma levels during hemodialysis have recently been considered markers of membrane biocompatibility. The aim of this study was to assess if generation of beta 2m from blood cells in contact with the membrane could account for changes in beta 2m plasma concentration during hemodialysis. The role of heparin was studied as well by comparing conventional with heparin-free dialysis. beta 2m plasma levels were measured in six patients during 12 Cuprophan (Cu) and 12 Eval (E) non-consecutive hemodialysis sessions without ultrafiltration. E membranes were compared with and without heparin. beta 2m plasma levels significantly increased with Cu but not with E. A total of 200 ml of blood from four other patients was recirculated ex vivo before Cu hemodialysis in Cu or E and then reinfused into the patient. A drop in beta 2m concentration was observed in the recirculating blood, recovery of beta 2m from the washed filter was higher with E, and reinfusion of recirculated blood to the patient was not associated with significant increases in beta 2m plasma levels. Hemodialysis with a new Cu filter, following reinfusion, did not produce significant increase in plasma beta 2m concentration. In conclusion, 1) beta 2m plasma levels change during Cu, but are not associated with hemoconcentration from ultrafiltration nor with local release from the blood leaving the filter, 2) beta 2m binding to the membrane may account for decreased levels in recirculated blood, 3) E membranes both with and without heparin do not increase beta 2m plasma levels and reinfusion of recirculated blood blunts the beta 2m changes observed with Cu.

Aged↗

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Plasma perfusion in myasthenia gravis.

Seven patients with myasthenia gravis (MG) unresponsive to thymectomy and steroid treatment (Osserman group III) underwent plasma perfusion (PP). All patients showed palpebral ptosis, diplopia, dysphonia, dysphagia, and muscle weakness; five of them had impaired ventilatory function. Separated plasma was perfused onto a column to adsorb anti-AChR-Ab. Each patient received a treatment cycle of six PP sessions. Clinical conditions were assessed before and after the treatment, with evaluation of muscular strength, ventilatory function, and electromyographic testing (RSS). Immunologic markers were tested before and after each PP. Clinical improvement in bulbar symptoms and respiratory function was noted in all patients after one to three PP. Limb muscle strength began to improve later. Serum concentration decreased (mean % +/- SD) after each PP:anti-AChR-Ab 36.47 +/- 17.43; IgA 20.44 +/- 11.26; IgG 21.24 +/- 32.56; IgM 23.22 +/- 11.40; C3 36.78 +/- 10.15; C4 42.69 +/- 14.82. In five of seven patients the improvement continues (follow-up 1 to 10 months). In one patient it lasted only 1 month, and in another a relapse occurred after 10 months of benefit, but was successfully reversed by retreatment.

Adult↗

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