IL-5 receptor ? levels in patients with marked eosinophilia or mastocytosis.

ABSTRACT:

Background

IL-5 plays a central role in the development and maintenance of eosinophilia (EO) and eosinophil activation in a wide variety of eosinophilic disorders. Although IL-5, IL-3, and GM-CSF can modulate the expression of IL-5 receptor ? (IL-5R?) on eosinophils in vitro, little is known about soluble and surface IL-5R? levels in vivo.

Objective

To assess soluble and surface IL-5R? levels in patients with EO and/or mastocytosis.

Methods

Surface IL-5R? expression was assessed by flow cytometry in blood and/or bone marrow from subjects with EO (n = 39) and systemic mastocytosis (n = 8) and from normal volunteers (n = 28). Soluble IL-5R? (sIL-5R?) level was measured in a cohort of 177 untreated subjects and correlated with EO, eosinophil activation, and serum tryptase and cytokine levels.

Results

IL-5R? expression on eosinophils inversely correlated with EO (r = -0.48; P < .0001), whereas serum levels of sIL-5R? increased with the eosinophil count (r = 0.56; P < .0001) and serum IL-5 (r = 0.40; P < .0001) and IL-13 (r = 0.29; P = .004) levels. Of interest, sIL-5R? level was significantly elevated in patients with systemic mastocytosis without EO. Although sIL-5R? levels correlated with serum tryptase levels in these patients, eosinophil activation, assessed by CD69 expression on eosinophils and serum eosinophil-derived neurotoxin levels, was increased compared with that in normal subjects.

Conclusions

These data are consistent with an in vivo IL-5R? regulatory pathway in human eosinophils similar to that described in vitro and involving a balance between soluble and surface receptor levels. This may have implications with respect to the use of novel therapeutic agents targeting IL-5 and its receptor in patients with EO and/or mastocytosis.

SUBMITTER: Wilson TM 

PROVIDER: S-EPMC3205313 | biostudies-literature | 2011 Nov

REPOSITORIES: biostudies-literature