Reply

Abstract

We thank Thomson et al for their thoughtful letter and questions regarding our study and will elaborate on their comments. Generally, the specificity of different antibodies used in immunolocalization studies can be varied. Indeed, Eis et al1Eis ALW Brockman DE Myatt L Immunolocalization of the inducible nitric oxide synthase isoform in human fetal membranes.Am J Reprod Immunol. 1997; 38: 289-294Crossref PubMed Scopus (20) Google Scholar agreed with our findings that no inducible nitric oxide synthase immunostaining was identified in human amnion epithelium but was found in fibroblasts of human amnion. Although Dennes et al (see reference 2 of Thomson et al) identified inducible nitric oxide synthase messenger ribonucleic acid in human amnion at term by polymerase chain reaction, the expression was at least 30-fold lower than in chorion-decidua. We suspect that a weak expression of inducible nitric oxide synthase in human amnion in that study may be caused by fibroblasts but not epithelium of human amnion. We agree that we should provide the inducible nitric oxide synthase expression on human neutrophils2Wheeler MA Smith SD García-Cardeña G Nathan CF Weiss RM Sessa WC Bacteria infection induces nitric oxide synthase in human neutrophils.J Clin Invest. 1997; 99: 110-116Crossref PubMed Scopus (246) Google Scholar, 3Tsukahara Y Morisaki T Horita Y Torisu M Tanaka M Expression of inducible nitric oxide synthase in circulating neutrophils of the systemic inflammatory response syndrome and septic patients.World J Surg. 1998; 22: 771-777Crossref PubMed Scopus (39) Google Scholar instead of rodent macrophages. However, we disagree with the comments by Thomson et al regarding no expression of inducible nitric oxide synthase in human neutrophils. Evidence that human neutrophils express inducible nitric oxide synthase or its products has been inconclusive and controversial. Recently, Wheeler et al2Wheeler MA Smith SD García-Cardeña G Nathan CF Weiss RM Sessa WC Bacteria infection induces nitric oxide synthase in human neutrophils.J Clin Invest. 1997; 99: 110-116Crossref PubMed Scopus (246) Google Scholar and Tsukahara et al3Tsukahara Y Morisaki T Horita Y Torisu M Tanaka M Expression of inducible nitric oxide synthase in circulating neutrophils of the systemic inflammatory response syndrome and septic patients.World J Surg. 1998; 22: 771-777Crossref PubMed Scopus (39) Google Scholar have clearly demonstrated that inducible nitric oxide synthase can be induced in human neutrophils.