Reduced PMN β2 integrins after trauma: a possible role for colony-stimulating factors

Abstract

SUMMARYThe /?i integrins are composed of a common 95-kD ^-subunit (CD 18) and one of three possible atsubunils: CDIIa. CDlIb. or CDMc. These molecules arc involved in neutrophil adhesion, diapodesis, chemotaxis and phagocytosis. In ihis study, the elTects oftrauniatic injury on neutrophi! expression of these a-subunits were investigated. Neutrophils from patients with severe trauma (rt = 30) were stained with fluorescent anti-CD 1 la, -CDI lb, or -CDl Ic. The percentage ofpositive neutrophils and the mean channel fluorescence were assayed by flow cytometry. In 10 patients and 10 normals, the elTects of granulocytc-colony stimulating factor (G-CSF) and granulocyte-niacrophage colony-stimulating factor (GM-CSF) on a-subunit expression were evaluated. Ninety-four ±2% (s.e.m.) of normal neutrophils were CDl la*, 89+1% were CDIIb' and 89 + 8% were CDllc+. Only 65 +2% of patient neutrophils wereCDlIa^,45±5% we reCDIlb* and 8+l%wereCDIlc'. Culture of normal neutrophils without colony-stimulating factors resulted in reduced expression of CDlla and CDlIc, bul up-regulation of CDllb. Down-regulalion of CDl la and CDIIc was partially reversed by colony-stimutating factors (30 U/ml). CD! lb receptor density was further upregulated by GM-CSF and G-CSF. Treatment of patient neutrophiis with colony-stimulating factors in culture resulted in up-regulation of a-subunits as well. GM-CSF appeared to have the greater effect. These results indicate that colony-stimulating factors may have a clinical role in improving ^2 integrin expression, and suggest a use in these infection-prone patients.