Lymphocyte ultrastructure in two cases of neuronal ceroid-lipofuscinosis.

Circulating blood lymphocytes from two patients with neuronal ceroid-lipofuscinosis (NCL) were investigated by transmission electronmicroscopy. Ultrastructural examination showed two forms of intracytoplasmic single membrane-limited inclusions. Contents of the first inclusion form were arranged in five distinct patterns: (1) granules, (2) membranous formations, (3) paracrystalline forms, (4) alternating electron-dense/electron-lucent arrangements, and (5) admixtures of these components. These molecular morphologies suggest the usefulness of lymphocyte fine structure as a diagnostic tool in NCL. The second inclusion form contained cylinder-like structures. These structures are not specific for NCL and have been identified in other diseases.