Mucopolysaccharidosis type VII. A morphologic, cytochemical, and ultrastructural study of the blood and bone marrow.

The morphologic, cytochemical, and ultrastructural pathology of the blood and bone marrow of an infant with Mucopolysaccharidosis Type VII (MPS VII) is reported. The neutrophils, monocytes, basophils, and eosinophils contained prominent granulation of the Alder-Reilly type. The lymphocytes, plasma cells, osteoblasts, and macrophages contained cytoplasmic inclusions surrounded by clear vacuoles. Cytochemically, the granulocytes, monocytes, and lymphocytes were negative for beta-glucuronidase, negative or weakly metachromatic with toluidine blue, and positive for acid phosphatase. Macrophages were negative with toluidine blue. A normal staining pattern was present with myeloperoxidase and periodic acid-Schiff (PAS). Ultrastructural studies showed abnormal vacuoles in neutrophils, basophils, eosinophils, monocytes, lymphocytes, plasma cells, and macrophages. Occasional vacuoles contained Ruthenium Red positive material and confirmed the presence of acid mucopolysaccharide in these cells. This report confirms previously described abnormalities in peripheral blood cells in MPS VII, demonstrates additional abnormalities in bone marrow, and reports cytochemical reactions in leukocytes in MPS VII.