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Propionibacterium acnes-Reactive T Helper-1 Cells in the Skin of Patients with Acne Vulgaris

2003; Elsevier BV; Volume: 121; Issue: 5 Linguagem: Inglês

10.1046/j.1523-1747.2003.12550_6.x

1523-1747

Paul Mouser, Edward Seaton, Anthony C. Chu, Barbara S. Baker,

melanin and skin pigmentation

To the Editor: Acne vulgaris is the commonest skin disorder to affect humans, characterized by both noninflammatory (comedones) and inflammatory lesions (papules, pustules, and nodulocystic lesions). It is a disease of the pilosebaceous follicle with comedones resulting from the hypercornification of the keratinocytes of the duct wall and usually preceding inflammatory lesions (Cunliffe et al., 2000Cunliffe W.J. Holland D.B. Clark S.M. Stables G.I. Comedogenesis: Some new aetiological, clinical and therapeutic strategies.Br J Dermatol. 2000; 142: 1084-1091Crossref PubMed Scopus (154) Google Scholar). Of particular interest in the pathophysiology of inflammatory acne is the role of the normal skin commensal bacterium Propionibacterium acnes. Although not a requirement for comedogenesis, a number of observations have suggested that P. acnes is implicated in the pathogenesis of inflammatory acne. The density of P. acnes increases markedly during puberty coinciding with the onset of the disease (Leyden et al., 1975Leyden J.J. McGinley K.J. Mills O.H. Kligman A.M. Age-related changes in the resident bacterial flora of the human face.J Invest Dermatol. 1975; 65: 379-381Crossref PubMed Scopus (132) Google Scholar). P. acnes is rarely found in animal skin and acne is not seen in animals (Webster et al., 1981Webster G.F. Ruggieri M.R. McGinley K.J. Correlation of Propionibacterium acnes populations with the presence of triglycerides on nonhuman skin.Appl Environ Microbiol. 1981; 41: 1269-1270PubMed Google Scholar;Kearney et al., 1982Kearney J.N. Gowland G. Holland K.T. Cunliffe W.J. Maintenance of the normal flora of human skin grafts transplanted to mice.J Gen Microbiol. 1982; 128: 2431-2437PubMed Google Scholar). Treatments that reduce P. acnes numbers lead to clinical improvement of acne (Thiboutot, 1997Thiboutot D.M. Acne. An overview of clinical research findings.Dermatol Clin. 1997; 15: 97-109Abstract Full Text Full Text PDF PubMed Scopus (73) Google Scholar) and, finally, the emergence of antibiotic-resistant P. acnes strains are linked to the failure of antibiotic treatment (Eady et al., 1989Eady E.A. Cove J.H. Holland K.T. Cunliffe W.J. Erythromycin resistant propionibacteria in antibiotic treated acne patients: Association with therapeutic failure.Br J Dermatol. 1989; 121: 51-57Crossref PubMed Scopus (267) Google Scholar). The immunostimulatory activity of P. acnes and resulting prototypic T helper 1 immune response has been widely studied in animal models (Matsui et al., 1997Matsui K. Yoshimoto T. Tsutsui H. et al.Propionibacterium acnes treatment diminishes CD4+ NK1.1+ T cells but induces type I T cells in the liver by induction of IL-12 and IL-18 production from Kupffer cells.J Immunol. 1997; 159: 97-106PubMed Google Scholar;Okazaki et al., 2001Okazaki T. Ozaki S. Nagaoka T. et al.Antigen-specific T(h) 1 cells as direct effectors of Propionibacterium acnes-primed lipopolysaccharide-induced hepatic injury.Int Immunol. 2001; 13: 607-613Crossref PubMed Scopus (7) Google Scholar); however, the specificity and cytokine profiles of lesional T cells from skin of acne patients have not been investigated previously. Here we describe the generation of T cell lines (TCL) from inflamed acne lesions, and, their proliferative and cytokine responses to P. acnes antigens. Approval was granted for this research project by the Hammersmith Queen Charlotte's & Chelsea and Actin Hospitals Research Ethics Committee. Full consent was granted by subjects. Fourteen TCL were generated from early papular inflammatory acne lesions of 16 untreated patients, stained for CD4, CD8, and T cell receptor αβ expression and tested in proliferation assays with P. acnes and control antigens (Figure 1). To determine their cytokine profile, TCL were stimulated with phorbal 12-myristate 13-acetate (PMA) plus ionomycin or P. acnes extract and stained intracellularly for interferon (IFN)-γ, interleukin (IL)-4, IL-5, and IL-10 using flow cytometry. Results were compared with eight corresponding TCL generated in the same way from lesional skin of 11 psoriatic patients. Acne TCL consisted of T cell receptor αβ+ T cells (96.4±4%) with a predominance of CD4+ (92±7.5%) phenotype, whereas psoriatic TCL contained a higher percentage of CD8+ T cells (24.8+21.4%; p<0.05). This is in agreement with an earlier immunohistochemical study that demonstrated perivascular and periductal infiltrates of CD4+ T cells in early acne skin lesions (Layton et al., 1998Layton A.M. Morris C. Cunliffe W.J. Ingham E. Immunohistochemical investigation of evolving inflammation in lesions of acne vulgaris.Exp Dermatol. 1998; 7: 191-197Crossref PubMed Scopus (60) Google Scholar); however, the stimulus for T cell infiltration into acne lesions remains to be determined. The initial T cell infiltrate may represent a specific cell-mediated immune response to P. acnes antigens within the ductal lumen. In support of this hypothesis, this study has shown that all acne TCL proliferated to P. acnes extract (optimal concentration 1:100) with a wide range of responses (mean 6420±4545 cpm) (Figure 1). Anti-HLA-DR antibody (10 μg per mL) induced 77.4 to 100% inhibition of the proliferative response in seven of eight TCL tested suggesting that antigens and/or superantigens, rather than mitogens were responsible for the T cell activation, but CDR3 spectratyping of P. acnes-reactive TCL and major histocompatibility complex restriction studies are needed to analyze the exact nature of the response. In contrast, the eight psoriatic TCL also generated with P. acnes showed no or only a minimal response to P. acnes (mean 453±459 cpm), which was significantly lower than that of the acne TCL (p≤0.001) (Figure 1). Of the eight acne TCL tested with control antigens Pityrosporum ovale and group A streptococci (Strep A), only three responded very weakly to P. ovale, a skin commensal also present in acne lesions (Marples, 1974Marples R.R. The microflora of the face and acne lesions.J Invest Dermatol. 1974; 62: 326-331Crossref PubMed Scopus (57) Google Scholar;Leeming et al., 1984Leeming J.P. Holland K.T. Cunliffe W.J. The microbial ecology of pilosebaceous units isolated from human skin.J Gen Microbiol. 1984; 130: 803-807PubMed Google Scholar), whereas six proliferated poorly to Strep A, an organism that is ubiquitous to humans (Baker et al., 1999Baker B.S. Brown D. Porter W. Hardman C. Garioch J.J. Powles A. Fry L. T lymphocytes reactive for group A streptococcal antigens in chronic plaque psoriatic lesions.Arch Dermatol Res. 1999; 291: 564-566Crossref PubMed Scopus (13) Google Scholar). The majority of T cells in the acne TCL expressed IFN-γ in response to PMA and ionomycin (mean 62.9±8.4%), whereas a smaller percentage (mean 13±3.5%) of IFN-γ+ T cells were expressed after P. acnes stimulation (Figure 2). A small proportion of IL-4+ T cells were detected after PMA/ionomycin (1.1±1.5%) or P. acnes (2±1.6%) stimulation (Figure 2). A low proportion (range 0–5.6%) of IFN-γ+, IL-4+ T cells were detected, whereas IL-5 and IL-10 levels were very low or rarely detected. Psoriatic TCL also expressed a high percentage of IFN-γ+ T cells (range 58.9–78.1%) after PMA/ionomycin stimulation, but no IFN-γ+ or IL-4+ T cells were expressed after specific stimulation with P. acnes. This T helper 1 cytokine pattern of high IFN-γ, low IL-4 production by the acne T cells is usually associated with both effective cellular immune responses against bacteria and with T cell mediated autoimmune tissue injury (Abbas et al., 1996Abbas A.K. Murphy K.M. Sher A. Functional diversity of helper T lymphocytes.Nature. 1996; 383: 787-793Crossref PubMed Scopus (3859) Google Scholar). Thus IFN-γ may play a central part in the immunopathogenesis of acne. Its various effects include induction of E-selectin on endothelial cells (Leeuwenberg et al., 1990Leeuwenberg J.F. von Asmuth E.J. Jeunhomme T.M. Buurman W.A. IFN-gamma regulates the expression of the adhesion molecule ELAM-1 and IL-6 production by human endothelial cells in vitro.J Immunol. 1990; 145: 2110-2114PubMed Google Scholar) and the induction of intercellular adhesion molecule-1 and HLA-DR on keratinocytes (Griffiths et al., 1989Griffiths C.E. Voorhees J.J. Nickoloff B.J. Characterization of intercellular adhesion molecule-1 and HLA-DR expression in normal and inflamed skin: Modulation by recombinant gamma interferon and tumor necrosis factor.J Am Acad Dermatol. 1989; 20: 617-629Abstract Full Text PDF PubMed Scopus (458) Google Scholar) all of which are strongly expressed in early inflammatory acne lesions (Layton et al., 1998Layton A.M. Morris C. Cunliffe W.J. Ingham E. Immunohistochemical investigation of evolving inflammation in lesions of acne vulgaris.Exp Dermatol. 1998; 7: 191-197Crossref PubMed Scopus (60) Google Scholar). Furthermore, P. acnes may also contribute to inflammation by induction of IL-8 and IL-12 production by monocytes via activation of Toll-like receptor 2 (Kim et al., 2002Kim J. Ochoa M.T. Krutzik S.R. et al.Activation of toll-like receptor 2 in acne triggers inflammatory cytokine responses.J Immunol. 2002; 169: 1535-1541Crossref PubMed Scopus (524) Google Scholar). In this study we have demonstrated that a subpopulation of T helper 1 cells generated from early inflamed acne lesions recognize P. acnes antigens. Further studies are required to determine the possible role of these T cells in the immunopathogenesis of this common skin disease. This work was supported by a grant from Leo Pharmaceuticals.