Immunogold localization of multimerin in patient (III-1) and control platelets. (a) The characteristic, eccentric labeling of α-granular (A) multimerin17 (arrowheads) is seen in the control platelets. The plasma membrane (pm) and open cannalicular system (ocs) are not labeled. (b) The patient's platelets contain fewer immunogold particles per α-granule (A). However, the eccentric multimerin labeling pattern is preserved and no gold particles are found in structures other than α-granules. (Original magnification × 65,000 for both panels.)