Reduced priming effect of interleukin 3 on IgE mediated basophil histamine release in patients with systemic sclerosis.
OBJECTIVE
To determine the capacity of interleukin 3 (IL-3) to induce and enhance basophil histamine release in patients with systemic sclerosis (SSc).


METHODS
Leukocyte suspensions prepared by dextran sedimentation of peripheral venous blood were stimulated with anti-IgE (10 microg/ml), N-formyl-methionyl-leucyl-phenylalanine (fMLP, 1 microM), and IL-3 (0.1 to 10 ng/ml). The priming effect of IL-3 on anti-IgE and fMLP induced histamine release was evaluated. Histamine release was measured by an automated fluorometric method.


RESULTS
No significant difference was found between patients with SSc (n = 12) and control subjects (n = 16) regarding spontaneous IL-3 and fMLP induced histamine release. IL-3 was a weak basophil agonist in both populations, since net histamine release did not exceed 10% of total histamine content in any case. Anti-IgE induced histamine release was lower in patients with SSc than in controls (13.09 +/- 4.8 vs 30.2 +/- 6.2%; p = 0.048). IL-3 enhanced anti-IgE and fMLP induced histamine release in a dose dependent fashion. However, the enhancement of anti-IgE induced histamine release by IL-3 was significantly lower in patients with SSc than in controls (p < 0.01 at 0.1 ng/ml IL-3; p < 0.05 at 1 and 10 ng/ml IL-3). In contrast, no difference was found between the 2 populations regarding the enhancement of fMLP induced histamine release by IL-3.


CONCLUSIONS
Basophil response to anti-IgE and the priming effect of IL-3 on IgE mediated basophil histamine release are lower in patients with SSc than in controls. These alterations could be related to chronic activation of the IgE/basophil system in patients with SSc.
Third Division of Internal Medicine, IRCCS Ospedale Maggiore Policlinico, Milan, Italy.
A
A
Tedeschi
C
C
Salmaso
N
N
Milazzo
A
A
Miadonna
D000328:Adult; D000368:Aged; D000888:Antibodies, Anti-Idiotypic / Q000494:pharmacology; D001491:Basophils / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006632:Histamine / Q000378:metabolism*; D006801:Humans; D007073:Immunoglobulin E / Q000494:pharmacology; D007377:Interleukin-3 / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D012595:Scleroderma, Systemic / Q000378:metabolism*
D000888:Antibodies, Anti-Idiotypic; D007377:Interleukin-3; C026408:anti-IgE antibodies; D007073:Immunoglobulin E; D009240:N-Formylmethionine Leucyl-Phenylalanine; D006632:Histamine