Autoimmunity in Patients Treated With Levodopa

To the Editor:— During our early studies of Parkinsonism with D,L DOPA1and during those with the L-isomer2,3Coombs tests were performed frequently. Continuation of this practice was indicated both on general grounds4and on the basis of a precedent with a DOPA derivative, namely D,L-a-methyldopa. This latter compound is serving in the management of hypertension under the trade name Aldomet. A toxic manifestation of methyldopa is the development of a positive Coombs test usually unaccompanied by demonstrable hemolysis.5,6We have encountered a similar change during the long-term administration of levodopa (L-DOPA) in the large amounts presently necessary to control Parkinsonism. Among 43 individuals treated during the last 3 1/2 years with either or both forms of DOPA, positive direct Coombs tests recently developed in four. These individuals also displayed positive indirect tests the titers of which were low (1:0 to 1:8). In two patients these