Peripheral blood lymphocyte appearance in a case of I cell disease

• Published in: Journal of clinical pathology 2001-09, Vol.54 (9), p.724-726
• Main Authors: van der Meer, W, Jakobs, B S, Bocca, G, Smeitink, J A M, Schuurmans Steckhoven, J H, de Keijzer, M H
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Blood; Causes of; Diagnosis, Laboratory; Disease; Enzymes; Errors of metabolism; Erythrocytes; Female; Fibroblasts; Humans; I cell disease; inclusion bodies; Infant, Newborn; Lipids (lysosomal enzyme disorders, storage diseases); Lymphocytes; Lymphocytes - ultrastructure; Lysosomes; Medical sciences; Mental retardation; Metabolic diseases; Microscopy; Mucolipidoses - pathology; Neutrophils; Phosphatase; Physiological aspects; Plasma; Proteins; Short Report; Vacuoles - ultrastructure
• ISSN: 0021-9746; 1472-4146
• DOI: 10.1136/jcp.54.9.724

In general, peripheral blood smears are performed to obtain information with regard to various morphological features as an aid in the diagnosis of infection or malignancy. This report presents a patient with I cell disease (inclusion cell disease), a fatal lysosomal storage disorder caused by a defect in an enzyme responsible for the transfer of mannose-6-phosphate ligands to precursor lysosomal enzymes. As a consequence, most lysosomal enzymes are transported outside the cell instead of being correctly targeted into the lysosomes, resulting in the storage of macromolecules in lysosomes. I cell disease, with its heterogeneous clinical presentation, can be diagnosed by the presence of intracellular vacuole-like inclusions in lymphocytes and fibroblasts, high serum lysosomal enzyme activities, and a defect of N-acetylglucosamine-1-phosphotransferase. This report describes the morphological aspects of peripheral lymphocytes in a blood smear of a patient, the first clue to the final diagnosis of I cell disease. The observed vacuole-like inclusions in lymphocytes of this patient were negative for periodic acid Schiff (PAS) and Sudan black B staining, in contrast to earlier reports.