The lipoprotein profile and phospholipase activity of subretinal fluid.

We have studied the lipoprotein profile of subretinal fluid by crossed immunoelectrophoresis using an antiserum against apolipoprotein A-I. If the detachment had occurred recently, we found that the subretinal fluid contained only the alpha 1-lipoprotein of serum. However, if the detachment was of longer duration an increasing amount of an electrophoretically slower-moving lipoprotein was also present in the subretinal fluid. We present evidence that subretinal fluid contains an enzyme, phospholipase A, which can form the slower-moving component from alpha 1-lipoprotein. Since the retina has a high phospholipid content, permanent damage may be caused to its structure by the action of this hydrolysing enzyme.