Inhibition of the sodium, potassium adenosine triphosphatase enzyme in peripheral blood mononuclear cells of subjects with allergic rhinitis.
BACKGROUND
Previous investigations have documented that a sodium, potassium adenosine triphosphatase (Na+,K+ ATPase) enzyme inhibitor is bound to the platelet membrane, displaced from the platelet membrane by freezing, and present in the plasma of subjects with allergic rhinitis. Others have shown that stimulation of Na+,K+ ATPase is an important early event in mitogen-induced activation of peripheral blood mononuclear cells.


OBJECTIVE
The purpose of this study was to determine whether the Na+,K+ ATPase enzyme inhibition observed in the platelets of subjects with allergic rhinitis also extends to peripheral blood mononuclear cells.


METHODS
Na+,K+ ATPase activity of a particulate fraction of sonicated peripheral blood mononuclear cells was determined by spectrophotometry in asymptomatic adults with and without allergic rhinitis.


RESULTS
The mean Na+,K+ ATPase activity of peripheral blood mononuclear cells expressed as nanomoles per microgram protein per minute (nM/ microgram protein/ min) +/-1 standard deviation of the subjects with allergic rhinitis (n = 14) was 1.04 +/- 1.01, while that of the control subjects (n = 12) was 3.57 +/- 1.60 (P < or = .001). In contrast, when the peripheral blood mononuclear cell membranes were frozen and then thawed prior to assay, the mean Na+,K+ ATPase activity for the subjects with allergic rhinitis (n = 24) was 5.33 +/- 2.62, while that of the control subjects (n = 23) was 1.12 +/- 1.24 (P < or = .001). Samples from a subset of subjects (n = 5) were assayed for both pre-freezing and post-freezing Na+,K+ ATPase activity. The freezing process was associated with a striking increase in Na+,K+ ATPase levels of subjects with allergic rhinitis (4.42 +/- 2.06) but a decrease in those of the control subjects (-3.89 +/- 0.95; P < or = .001).


CONCLUSIONS
These data demonstrate that peripheral blood mononuclear cells from subjects with allergic rhinitis, like platelets, possess a membrane-bound Na+,K+ ATPase inhibitor that is displaced from the membrane by freezing. In vivo Na+,K+ ATPase inhibition could have significant effects on the activation and function of peripheral blood mononuclear cells in subjects with allergic rhinitis.
Van Deusen
M A
MA
Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pennsylvania.
Gentile
D A
DA
Skoner
D P
DP
D005615:Freezing; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000201:enzymology*; D012221:Rhinitis, Allergic, Perennial / Q000097:blood* / Q000201:enzymology; D006255:Rhinitis, Allergic, Seasonal / Q000097:blood* / Q000201:enzymology; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors* / Q000378:metabolism
D000254:Sodium-Potassium-Exchanging ATPase