Biochemical and ultrastructural findings in a lymphoid cell line from Niemann-Pick disease type A.

A lymphoid cell line (LCL) established by Epstein-Barr Virus (EBV)-transformation of blood B-lymphocytes from a patient affected with Niemann-Pick disease (NPD) Type A exhibited a severe deficiency of sphingomyelinase activity (less than 10% residual activity). Ultrastructural investigation showed in LCL from NPD type A, the presence of numerous osmiophilic, electron-dense inclusions with myelin-like figures characteristic of the accumulation of sphingomyelin (and other amphiphilic lipids) similar to those observed in tissues of patients affected with NPD.