Decreased activity of the platelet Na+,K(+)-adenosine triphosphatase enzyme in allergic subjects.
A pathogenic role and abnormal function have both been ascribed to the blood platelet in allergy, but the explanation for these observations is unknown. This study compared the cation-stimulated adenosine triphosphatase enzyme (ATPase) activities of platelets from allergic (n = 18), potentially allergic (asymptomatic, positive skin test, n = 5) and normal patients (n = 10), all of whom were without symptoms at the time of the study. Platelets were separated by centrifugation, were sonicated, and were assayed for cation-dependent ATPase activity by spectrophotometry. The mean Na+,K(+)-ATPase activity (in nanomoles per microgram protein per minute) of allergic subjects (0.94 +/- 1.28) was significantly lower than that of normal subjects (3.93 +/- 1.58). No Na+,K(+)-ATPase activity was detectable in platelets from eight of the allergic subjects. The Na+,K(+)-ATPase activity of potentially allergic subjects was intermediate between those of the allergic and normal subjects. A significant negative correlation (p less than 0.01) was observed between serum IgE levels and platelet Na+,K(+)-ATPase values, thus suggesting a relationship between the reduced platelet Na+,K(+)-ATPase and IgE immunoglobulin. No such differences were observed for the Ca+(+)- and Mg+(+)-stimulated ATPases. In vivo dysfunction of the plasma membrane Na+,K(+)-ATPase enzyme in allergic subjects could have profound effects on levels of intracellular cations and thus platelet activation and function.
Skoner
D P
DP
Department of Pediatrics, University of Pittsburgh School of Medicine, PA.
Gentile
D
D
Evans
R
R
D000328:Adult; D001249:Asthma / Q000097:blood / Q000201:enzymology; D001792:Blood Platelets / Q000201:enzymology*; D017301:Ca(2+) Mg(2+)-ATPase / Q000097:blood; D000252:Calcium-Transporting ATPases / Q000097:blood; D006801:Humans; D006967:Hypersensitivity / Q000097:blood / Q000201:enzymology*; D007073:Immunoglobulin E / Q000032:analysis; D012016:Reference Values; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D007073:Immunoglobulin E; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase