Tolerance induction using the Malmö treatment model 1982-1995.

The ultimate goal in the treatment of haemophilia patients with inhibitors is to eradicate permanently the inhibitor and induce tolerance. Here we summarize our experience at the Malmö centre regarding tolerance induction according to the Malmö Treatment Model. The protocol includes immunoadsorption if needed, neutralization of inhibitor and replacement with factor concentrates, cyclophosphamide intravenously for 2 days (12-15 mg kg-1 bw) and then orally (2-3 mg kg-1 bw) for an additional 8-10 days and intravenous gammaglobulin daily at dosages of 0.4 g kg-1 bw for 5 days. This protocol has been applied in 23 haemophilia patients with inhibitors, 16 haemophilia A patients and seven haemophilia B patients. Altogether 36 attempts have been made to induce tolerance. Ten of the 16 haemophilia A (62.5%) and 6/7 patients with haemophilia B (86%) became tolerant after the treatment. The chances of success or failure are roughly equal, if the series is considered in a historical perspective. The data showed that the chances of success in tolerance induction with the Malmö protocol were best in those patients with low inhibitor titres, with relatively low historical inhibitory peak and with a long interval since the previous replacement therapy. This was especially true where no inflammatory state was present at the start or during tolerance induction. The advantage with this method compared to the high-dose regimen is that in the successful cases tolerance can be achieved within 3-4 weeks.

Immunoadsorption for removal of inhibitors: update on treatments in Malmö-Lund between 1980 and 1995.

Treatment of severe bleeding and the performance of surgery in haemophilia patients with inhibitors creates severe problems. It is generally agreed that treatment is most effective if circulating levels of factor VIII/IX can be achieved long enough for control of haemostasis. Immunoadsorption with protein A for the removal of inhibitor has improved treatment for patients with initial inhibitor titres too high to neutralize by infusion alone. This is a summary of our experience in Malmö regarding immunoadsorption and haemostasis. A total of 19 applications with immunoadsorption in 10 patients were performed. On all occasions it was possible to eliminate totally the inhibitor or reduce it to low levels that could easily be neutralized with factor concentrate. Haemostatic levels of coagulation factors could be maintained for 5-9 days in all but one patient. This period was sufficient to stop ongoing haemorrhage or prevent excessive bleeding at surgical interventions.

A novel approach to monoclonal antibody separation using high performance liquid affinity chromatography (HPLAC) with SelectiSpher-10 protein G.

Protein G, a bacterial cell wall protein extracted from strains of Streptococci, has been employed as a ligand in high performance liquid affinity chromatography (HPLAC) for separation of monoclonal antibodies. Examples are given of rapid high-resolution separations of rat and mouse monoclonal antibodies belonging to various subclasses. In comparison with protein A chromatography, we were able to show superior binding characteristics for SelectiSpher-10 protein G columns under conditions of 'low' ionic strength (about 0.1 M) and neutral pH (pH approximately 7). The monoclonal antibodies were isolated in high purity (greater than 90%) and with good recovery of specific activity (80-100%). We believe that the HPLAC technology based on SelectiSpher-10 protein G is of potential value in the analysis and purification of monoclonal antibodies from various species and subclasses.

Behavioral effects of thymoleptics in vervet monkeys (Cercopithecus aethiops).

Desmethylimipramine (DMI) exerts diverse quantitative effects on the gross behaviour of monkeys. Excitatory as well as sedative effects were observed, which varied according to the general animal temperament. Results resembling those obtained with DMI were observed using chlorimipramine and iprindole, although the effects of iprindole were less marked. Chlorimipramine also produced immobilization and postural change. The results are discussed in relation to behavioral effects of thymoleptics in humans, and the use of monkeys in preclinical testing of thymoleptic drugs is suggested.

Comparative studies of a new 5HT-uptake inhibitor and some tricyclic thymoleptics.

The new 5HT-uptake inhibitor, FG 4963, and some tricyclic thymoleptics antagonized p-chloroamphetamine (PCA)-induced hypermotility in rats. FG 4963 was active in about the same s.c. and p.o. doses as chlorimipramine. FG 4963, imipramine and chlorimipramine potentiated hypermotility induced in mice by the 5HT precursor 5HTP, FG 4963 being slighly more active than chlorimipramine. In contrast to the tricyclic thymoleptics FG 4963 did not potentiate the heart rate increasing effect of NA in pithed rats. The peripheral anticholinergic effect of FG 4963 and of desipramine was almost identical while the other imipramine derivatives were more active. All tricyclic thymoleptics were strong peripheral antihistaminics, but FG 4963 was almost devoid of this action. Acute tests for ECG changes in guinea pigs and toxicity in mice and rats showed that FG 4963 and chlorimipramine were less toxic than imipramine and amitriptyline. FG 4963 is presumably a selective 5HT-uptake inhibitor producing much less potentiation of peripheral sympathetic mechanisms than do the tricyclic antidepressants.