ORIGINAL ARTICLE Expression of secretory leukocyte proteinase inhibitor in the submandibular glands of AIDS patients LA Rocha 1 , PA Vargas 1 , LFF Silva 2 , JE Leon 1 , AB Santos 2 , PS Hiemstra 3 , T Mauad 2 1 Department of Oral Pathology, Faculty of Odontology of Piracicaba- University of Campinas, Piracicaba, SP, Brazil; 2 Department of Pathology, Sa ˜o Paulo University Medical School, SP, Brazil; 3 Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands OBJECTIVE: Secretory leukocyte proteinase inhibitor (SLPI) is an endogenous proteinase inhibitor present in mucosal secretions. It also displays antimicrobial activity including anti-human immunodeficiency virus activity. This protease inhibitor is also expressed in submandibu- lar glands (SMG), but there are few data on its expression in AIDS patients with infectious conditions. METHODS: We analyzed the expression of SLPI using immunohistochemistry in submandibular gland samples of 36 AIDS patients [10 with normal histology, 10 with chronic nonspecific sialadenitis, eight with mycobacteri- osis, and eight with cytomegalovirus (CMV) infection] and 10 HIV-negative controls. The proteinase inhibitor was quantified using image analysis and expressed as % of positively stained area. RESULTS: There was a higher expression of SLPI in AIDS patients with CMV infection (% of stained area, mean ± SD: 37.37 ± 14.45) when compared with all other groups (P = 0.009). There were no significant differences between control subjects (22.70 ± 9.42%) and AIDS patients without histologic alterations (18.10 ± 7.58%), with chronic nonspecific sialadenitis (17.13 ± 5.36%), or mycobacterial infection (21.09 ± 4.66%). CONCLUSION: Cytomegalovirus infection increases SLPI expression in the SMG of AIDS patients. Our results reveal new insights into the pathogenic association between HIV and CMV in AIDS patients. Oral Diseases (2008) 14, 82–88 Keywords: secretory leukocyte proteinase inhibitor; subman- dibular gland; AIDS; immunohistochemistry; cytomegalovirus; autopsy Introduction The oral mucosa is exposed to high concentrations of microorganisms and relies on an effective innate immune system that provides host defense against infection. In particular, oral tissues are naturally resist- ant to the human immunodeficiency virus type 1 (HIV- 1) infection. A series of secreted antimicrobial factors present in the oral fluids have been implicated in this resistance, and include secretory leukocyte proteinase inhibitor (SLPI), defensins, salivary agglutinin, and thrombospondin (Shugars and Wahl, 1998; Shugars et al, 1999). Secretory leukocyte proteinase inhibitor is a cationic serine protease inhibitor present in large quantities in mucosal secretions including saliva. Originally, it was identified as an inhibitor of neutrophil elastase, but subsequent studies revealed broad-spectrum antimicro- bial activities, anti-inflammatory activities, and involve- ment in wound repair (Hiemstra, 2002; Sallenave, 2002; Doumas et al, 2005). Several studies have shown that SLPI displays marked anti-HIV-1 activity both in vivo and in vitro (McNeely et al, 1995; Shugars et al, 1997; Wahl et al, 1997b). This activity is thought to result from blocking an early step in infection that occurs prior to virus internalization and reverse transcription, as demonstrated by binding of SLPI to the HIV-1 co-factor annexin II (Shugars and Wahl, 1998; Shugars et al, 1999; Ma et al, 2004). Besides its anti-HIV-1 inhibitory action, SLPI has also been shown to possess antibacte- rial and antifungal properties (Hiemstra et al, 2004). In oral tissues, expression of SLPI has been demon- strated in keratinocytes, and in the major and minor salivary glands (Ohlsson et al, 1984; Jana et al, 2005). Lin et al (2004) demonstrated that SLPI concentrations in submandibular/sublingual and parotid saliva from HIV-infected individuals are higher than those in healthy subjects. In patients with advanced AIDS, the presence of inflammatory, infectious, and neoplastic diseases in the oral cavity is frequent. We have previously demonstra- ted the presence of inflammatory, infectious, and neoplastic abnormalities in 51% of the parotid glands Correspondence: T Mauad, Department of Pathology, Sa˜o Paulo University Medical School, Av Dr Arnaldo, 455 1st floor, CEP: 01246- 903, Sa˜ o Paulo, SP, Brazil. Tel: +55 11 30617173, Fax: +55 11 30642744, E-mail: tmauad@usp.br The authors of this paper do not have any commercial associations that might pose a conflict of interest in connection with this manuscript. Received 21 July 2006; revised 18 October 2006; accepted 2 November 2006 Oral Diseases (2008) 14, 82–88. doi:10.1111/j.1601-0825.2006.01358.x Ó 2007 The Authors. Journal compilation Ó 2007 Blackwell Munksgaard All rights reserved http://www.blackwellmunksgaard.com