IMPAIRMENT OF CALCIUM MOBILIZATION IN PHAGOCYTIC-CELLS IN GLYCOGEN-STORAGE-DISEASE TYPE-1B

Patients with glycogen storage disease (GSD) type 1b, in contrast to p atients with GSD 1a, are susceptible to recurrent bacterial infections suggesting defective phagocytic function. We have demonstrated a sele ctive defect in respiratory burst activity but not in degranulation by phagocytic cells in GSD 1b but not in GSD 1a. The respiratory burst a bnormality in phagocytic cells from GSD 1b patients was associated wit h impaired calcium mobilization, whereas these processes were normal i n GSD 1a patients. Therefore, the alteration in calcium mobilization w as an indication of a signalling defect in phagocytic cells from GSD 1 b. However, calcium mobilization was normal in lymphocytes, indicating that defective calcium mobilization was not a global finding in circu lating leukocytes, but was specific to phagocytic cells. Calcium mobil ization in response to ionomycin was reduced suggesting decreased calc ium stores in GSD 1b neutrophils. Therefore, altered phagocytic cell f unction in GSD 1b patients appears to be associated with diminished ca lcium mobilization and defective calcium stores. This defectice calciu m signalling was associated with a selective defect in respiratory bur st activity but not degranulation.