Suxamethonium histamine release from leucocyte

Fig. 3. Histamine release from the leucocytes of a patient with allergy to suxamethonium. Effect of serum (10%) on suxamethonium-induced histamine release. =control 5=suxamethonium 4- normal serum C=suxamethonium 4- patient s serum D = suxamethonium alone...

If suxamethonium acted as a bivalent allergen, it would be expected that acetylcholine would behave at least as a weak hapten, and that it would inhibit the response (histamine release) to suxamethonium. Figure 5 shows the result of adding acetylcholine to suxamethonium. In this experiment, a low concentration of acetylcholine (5 pg/ml) completely inhibited suxamethonium-induced histamine release from the leucocytes of a patient. It should be added that the specificity of inhibition by acetylcholine was confirmed by the lack of an inhibitory effect of acetylcholine on histamine release from human leucocytes induced by other allergens. 

Substantial release of histamine from basophil leucocytes could be elicited by suxamethonium in the absence of serum. The addition of serum to suxamethonium during leucocyte challenge would lead to rapid metabolism. We compared the effect of autologous serum from suxamethonium-reactive individuals with homologous serum from normal individuals (Fig. 3). The presence of normal serum in a 10% concentration completely abolished the release of histamine by suxamethonium from a patient s leucocytes. The patient s own serum had an almost identical effect. In fact, this patient s serum was found to have low cholinesterase activity, which might have accounted for the small response in the lymphocyte transformation test. 

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