VASOACTIVE INTESTINAL POLYPEPTIDE AS A BIOCHEMICAL MARKER FOR POLYMORPHONUCLEAR LEUKOCYTES

Abstract

VIP [Vasoactive intestinal poly peptide] is a 28 amino acid peptide found in highest concentration in central and peripheral nervous tissue. VIP was measured in pure populations of peripheral blood cells to determine the presence or absence of VIP in noninnervated tissues. Cell populations were purified by Ficoll-Hypaque gradient centrifugation followed by dextran sedimentation or differential adherence to culture plates. Platelets were purified by differential centrifugation. VIP was isolated by acid-ethanol extraction and quantified by radioimmunoassay. A mean value of 1.1 .+-. 0.6 ng of VIP per 108 cells was extracted from PMNs [polymorphonuclear leukocytes]. This peptide aapears to be a specific marker for PMNs, since it was not measurable in pure populations of lymphocytes, monocytes, erythrocytes or platelets. Mononuclear cells obtained from 5 patients with AML [acute myelocytic leukemia] and 7 patients with CML [chronic myelocytic leukemia] contained measurable VIP, whereas mononuclear cells from 9 of 10 patients with AMML [acute myelomonocytic leukemia] and from 5 patients with ALL [acute lymphocytic leukemia] contained very low or unmeasurable levels of VIP. Although the role of VIP in normal PMN function is unknown, measurement of VIP in leukemic cells may aid in the differential diagnosis of acute leukemias.