Anaphylactic reactions to modified fluid gelatins.

Use of modified fluid gelatins as a plasma expander is of interest in human clinical medicine due to osmotic pressure similarities with plasma proteins. However, adverse reactions such as urticaria, edema, and/or anaphylactic shock occur and can lead to diagnostic problems. In addition, mechanisms of these reactions are poorly understood. We report three cases of anaphylactic shock studied by skin tests and, for the first time, in vitro leukocyte histamine release (LHR). Intradermal skin tests were significantly positive for concentrations of 1:1000 to 1:10 of the commercial preparation used before the reaction in each patient. Thirty control subjects were negative even for the undiluted preparation. Positive LHR was obtained from patients' leukocytes washed and then incubated in Tris-albumin Ca++ Mg++ buffer with serial dilutions of fluid gelatins; controls were negative. Addition of D2O (50%) caused significant increase of LHR in patients but had no effect on controls. In conclusion, skin tests and LHR might be valuable in diagnosis of patients reactive to gelatins. Furthermore, these findings suggest release of mediators from mast cells or basophils, but discrimination between immunologic and idiosyncratic pharmacologic mechanism was not obtained.