Volume 121, Issue 1 , Pages 258-260, January 2008
The effect of etanercept on the human cutaneous allergic response
Article Outline
To the Editor:
Etanercept (Enbrel; Immunex Corp, Thousand Oaks, Calif) is a TNF receptor 2-Fc fusion protein approved for the treatment of rheumatoid arthritis, juvenile rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and psoriasis. It antagonizes the actions of both TNF-α and TNF-β, but most of its clinical efficacy is the consequence of TNF-α antagonism. TNF-α is a potent multifunctional cytokine produced by a wide variety of cell types and is important for host defense and inflammatory cell influx and activation.1 Recent studies have demonstrated that TNF-α levels are elevated in the lungs of patients with severe asthma, and neutralizing its activity may be an effective treatment.2, 3, 4 To date, however, no human studies have been conducted to explore the effect of TNF-α inhibition on allergic inflammation in the skin. We conducted this open trial to determine whether systemic administration of etanercept at doses effective for psoriasis could affect allergic responses in the skin.
This trial was approved by the institutional review board at Johns Hopkins University, and informed consent was obtained from each participant. Subjects between the ages of 18 and 65 years were enrolled if they had perennial allergic rhinitis and demonstrated a wheal size with mean diameter ≥12 mm 15 minutes after intradermal injection with one of the dust mite allergens (Dermatophagoides pteronyssinus or Dermatophagoides farinae; Greer Laboratories, Lenoir, NC). Exclusion criteria included any of the following: history of multiple sclerosis, optic neuritis, myelitis, lidocaine allergy, keloids, active tuberculosis, or a positive purified protein derivative test result without receiving appropriate medical therapy. Subjects were off antihistamines, antileukotrienes, and topical or systemic corticosteroids for at least 7 days before and throughout the study.
This was an open-label trial using intradermal skin test titration with increasing concentrations of D pteronyssinus or D farinae. The dose that achieved a wheal size with a mean diameter ≥12 mm was defined as dose X. The following week, dose X was injected into 2 locations on the volar forearm, and a 5-mm skin biopsy was performed 2 and 16 hours later. Etanercept 50 mg was administered subcutaneously immediately after the final skin biopsy, with 2 more doses given at 72-hour intervals. All doses were administered by study personnel. Twenty-four hours after the third and final dose of etanercept, 2 more intradermal injections of dose X were performed on the contralateral volar forearm, and skin biopsies were performed 2 and 16 hours later. Subjects returned in 14 days for a final visit to assess adverse events from the skin biopsies or etanercept treatment. Serum was obtained 16 hours after allergen challenge both before (eg, baseline measurement) and after etanercept treatment to measure drug levels.
The acute-phase response (APR) at 15 minutes and the late-phase response (LPR) at 16 hours were traced onto Scanpor tape (3M, St Paul, Minn). This tracing was scanned, and the area was measured in pixels (Image J software; National Institutes of Health, Baltimore, Md). A visual analog scale (0-10) was used to quantify pruritus during the APR and LPR using the phrase, “How much does your skin itch?” Etanercept levels in serum were measured by using an ELISA assay (Amgen, Thousand Oaks, Calif). The sensitivity of the assay was 0.62 ng/mL.
Formalin-fixed and paraffin-embedded skin sections were stained to enumerate eosinophils (EG2; Kabi Pharmacia, Rockville, Md), neutrophils (neutrophil elastase; Zymed, Carlsbad, Calif), macrophages (CD68; Dako, Carpinteria, Calif), T lymphocytes (CD3; Dako), cutaneous lymphocyte antigen (HECA452; BD Pharmingen, San Jose, Calif), and the expression of the endothelial adhesion molecules, vascular cell adhesion molecule 1 (VCAM-1), and E-selectin (R & D Systems, Inc, Minneapolis, Minn) as described previously.5 All comparisons were made using the Wilcoxon signed-rank test.
Ten subjects were enrolled and completed the trial. The mean age was 38 ± 3 years, with 6 male and 4 female subjects. Etanercept was well tolerated. Serum etanercept levels increased in all subjects from undetectable to 5849 ± 746 ng/mL (range, 2700-9800 ng/mL; P < .01).
Unexpectedly, a significant reduction in the size of the APR was observed after administration of etanercept (P = .02; Fig 1). The mean reduction of wheal size diameter was 16% ± 7.3%. No difference, however, was noted for the size of the LPR at 16 hours (P = .6). Subject-reported itch scores did not change after etanercept at either the APR or LPR time points (data not shown). A statistically significant increase in EG2+ (P = .04) and CD3+ cells (P = .001) was observed between the 2-hour and 16-hour biopsies without etanercept treatment, demonstrating that a robust cellular LPR was elicited with the allergen doses used. However, 3 doses of etanercept had no effect on the numbers of eosinophils, neutrophils, lymphocytes, or CD68+ macrophages observed in skin biopsies taken 2 or 16 hours after allergen injection (Table I). Similarly, there were no significant changes in the percentage of blood vessels that stained positively for VCAM-1 or E-selectin after the administration of etanercept.
Fig 1.
Effect of etanercept administration (Post) on the area of the APR measured at 15 minutes (ΔP = .02).
Table I. Measurement of cellular infiltrate and endothelial adhesion molecules in EPR and LPR skin biopsies before and after etanercept treatment
| 2 h | 16 h | |||||||
|---|---|---|---|---|---|---|---|---|
| Pre Rx (SD) | Post Rx (SD) | Mean change (SD) | P value | Pre Rx (SD) | Post Rx (SD) | Mean change (SD) | P value | |
| Cells/mm2 | ||||||||
 EG2+ | 77 (53) | 116 (84) | +38 (69) | .14 | 167 (144) | 151 (80) | −16 (147) | .68 |
| Neutrophil elastase+ | 471 (129) | 472 (167) | +1 (124) | .51 | 436 (165) | 411 (182) | −25 (187) | .37 |
| CD3+ | 17 (20) | 20 (23) | +3 (4) | .10 | 71 (37) | 71 (42) | +0.1 (42) | .61 |
| Cutaneous lymphocyte antigen+ | 8 (11) | 7 (4) | −1 (8) | .99 | 14 (12) | 10 (7) | −4 (7) | .42 |
| CD68+ | 161 (136) | 156 (133) | −5 (141) | .96 | 188 (96) | 254 (171) | +66 (118) | .20 |
| Percent of positive vessels | ||||||||
| E-selectin∗ | 56 (21) | 59 (17) | +1 (16) | .96 | 48 (21) | 52 (27) | 4 (26) | .59 |
| VCAM-1∗ | 1.8 (4) | 1.6 (4) | −0.2 (2) | .99 | 2.3 (4) | 2.3 (3) | 0 (4) | .75 |
∗Listed as a percentage of endothelial cells staining positive for adhesion molecule. |
TNF-α is thought to be important in allergic inflammation because it is released by mast cells and is a potent inducer of endothelial adhesion molecule expression and chemokine production.6, 7, 11, 12 Several publications have suggested that TNF antagonism is an effective therapy in specific asthma subsets.1, 2, 3 Using a model of cutaneous allergic inflammation, we observed a modest reduction in the size of the APR with no effect on the size, symptoms, or cellular features of the LPR. The lack of an LPR effect is not likely a result of inadequate cutaneous absorption of etanercept, because expected blood levels were achieved in all subjects, and the dose used in this study is effective in psoriasis. It therefore seems probable that the lack of an effect on the LPR reflects the biology of this model. Our results coupled with 2 case reports demonstrating little to no effect with the TNF antagonists infliximab or etanercept in subjects with atopic dermatitis (AD)8, 9 strongly suggest that AD, and the cutaneous LPR as a model of AD, are not TNF-mediated.13, 14, 15
Etanercept significantly reduced the size of the APR, which is consistent with the observation that sputum histamine was reduced in a recent study of etanercept (25 mg twice weekly) treatment in subjects with refractory asthma.3 It is therefore possible that etanercept inhibits the priming action of TNF-α on IgE-mediated mast cell histamine release or that it inhibits direct TNF-α effects such as the release of neurotransmitters from nerve endings in the skin, both of which are worthy of further study. Last, our finding suggests that etanercept may be an effective treatment for urticaria, as has been shown in a recent case report.10
We acknowledge the helpful discussions with Dr Robert Schleimer on study development and design, Joanne Alsruhe for tissue processing of skin biopsies, Carol Bickel for assistance with histopathologic cell counts, and Doris W. Tom, CLS, and Lennie Uy (Amgen, Inc) for their assistance with etanercept measurements.
References
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- The effects of a monoclonal antibody directed against tumor necrosis factor-alpha in asthma. Am J Respir Crit Care Med. 2006;174:753–762
- Evidence of a role of tumor necrosis factor alpha in refractory asthma. N Engl J Med. 2006;354:697–708
- Tumour necrosis factor (TNFalpha) as a novel therapeutic target in symptomatic corticosteroid dependent asthma. Thorax. 2005;60:1012–1018
- Cutaneous injection of RANTES causes eosinophil recruitment: comparison of nonallergic and allergic human subjects. J Immunol. 1997;159:2962–2972
- . Mast cells as a source of both preformed and immunologically inducible TNF-alpha/cachectin. Nature. 1990;346:274–276
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- Infliximab in the treatment of moderate to severe atopic dermatitis. J Am Acad Dermatol. 2005;52:522–526
- Etanercept is minimally effective in 2 children with atopic dermatitis. J Am Acad Dermatol. 2005;53:358–359
- Successful treatment of delayed pressure urticaria with anti-TNF-alpha. J Allergy Clin Immunol. 2007;119:752–754
- Human dermal mast cells contain and release tumor necrosis factor alpha, which induces endothelial leukocyte adhesion molecule 1. Proc Natl Acad Sci U S A. 1991;88:4220–4224
- TNF alpha mRNA expression in allergic inflammation. Clin Exp Allergy. 1991;21:745–750
- Biomolecular regulation of the IgE immune response, III: cytokine profiles in atopic dermatitis, inhalant allergy and non-allergic donors. Cytokine. 1996;8:651–657
- Differential in vivo cytokine mRNA expression in lesional skin of intrinsic vs. extrinsic atopic dermatitis patients using semiquantitative RT-PCR. Clin Exp Allergy. 2003;33:1717–1724
- Production of IL-4, IL-2, IFN-gamma, and TNF-alpha by peripheral blood mononuclear cells of patients with atopic dermatitis. J Dermatol Sci. 1992;3:172–180
Supported by National Institutes of Health grant # P01 AI050530 (B.S.B. and L.A.B.); a Fujisawa American Academy of Allergy, Asthma & Immunology Grant (E.C.); and an Immunex/Amgen Grant (B.S.B. and L.A.B.) to provide etanercept free of charge.
Disclosure of potential conflict of interest: B. S. Bochner has consultant arrangements with Amgen. The rest of the authors have declared that they have no conflict of interest.
PII: S0091-6749(07)02207-5
doi:10.1016/j.jaci.2007.10.044
© 2008 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.
Volume 121, Issue 1 , Pages 258-260, January 2008
