title: Peripheral blood lymphocyte appearance in a case of I cell disease.
abstract: 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.
authors.affiliation: Department of Clinical Chemistry, University Hospital Nijmegen St Radboud, 6500 HB Nijmegen, The Netherlands.
authors.forename: W
authors.initials: W
authors.lastname: van der Meer
authors.forename: B S
authors.initials: BS
authors.lastname: Jakobs
authors.forename: G
authors.initials: G
authors.lastname: Bocca
authors.forename: J A
authors.initials: JA
authors.lastname: Smeitink
authors.forename: J H
authors.initials: JH
authors.lastname: Schuurmans Steckhoven
authors.forename: M H
authors.initials: MH
authors.lastname: de Keijzer
mesh_terms: D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008214:Lymphocytes / Q000648:ultrastructure*; D009081:Mucolipidoses / Q000473:pathology*; D014617:Vacuoles / Q000648:ultrastructure