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Abnormal platelet function in Chediak-Higashi syndrome
Insights
Infants with Chediak-Higashi syndrome may have platelet storage pool disease, affecting platelet function. Ascorbate treatment did not improve these abnormal platelet functions in the studied infant.
Area of Science:
- Hematology
- Genetics
- Biochemistry
Background:
- Chediak-Higashi (C-H) syndrome is a rare genetic disorder.
- Platelet dysfunction can occur in C-H syndrome, but is not fully understood.
Observation:
- Platelets from an infant with C-H syndrome, without bleeding issues or accelerated phase, exhibited storage pool disorder characteristics.
- Abnormalities included impaired aggregation, reduced serotonin and nucleotide storage/release, and altered calcium content.
Findings:
- Platelet adenine nucleotide metabolism and [14C]adenine incorporation were largely normal.
- Mild impairment in nucleotide conversion to hypoxanthine was noted.
- Elevated platelet cyclic-AMP (c-AMP) normalized after ascorbate treatment, but platelet function remained abnormal, indicating c-AMP is not solely responsible.
Implications:
- This study highlights platelet storage pool disorder as a potential, often subclinical, manifestation of C-H syndrome.
- Findings suggest that abnormal platelet function in C-H syndrome is multifactorial and not solely driven by elevated c-AMP levels.
- Further research is needed to elucidate the precise mechanisms underlying platelet dysfunction in C-H syndrome.
Abstract:
Platelets in an infant with Chediak-Higashi (C-H) syndrome without bleeding manifestations and not in the accelerated phase showed abnormal function consistent with storage pool disorder as shown by abnormal aggregation, decreased storage capacity and release of [14C]5-HT, low endogenous 5-HT, reduced ATP and ADP with an increased ATP/ADP ratio, increased specific radioactivity of ADP after [14C]adenine labelling, decreased release of adenine nucleotides after stimulation, impaired secretion of acid hydrolases despite normal stores, and decreased calcium content. Incorporation of [14C]adenine into metabolic pool adenine nucleotides was normal. Nucleotide conversion to hypoxanthine in stimulated platelets was mildly impaired. Platelet cyclic-AMP (c-AMP) was initially elevated, but even when c-AMP returned to normal levels after ascorbate treatment, platelet function was not improved. Elevated intracellular c-AMP was not solely responsible for the abnormal platelet function.