The immunocompromised district: How the pieces of the puzzle gradually fell into place

Radiotherapy for oral cancer decreases the cutaneous expression of host defence peptides

INTRODUCTION

Bacterial resistance against antibiotics has become an increasing challenge in the treatment of cutaneous infections. Consequences can be severe, especially in infected wounds following previous local radiotherapy. Certain endogenous peptide antibiotics, the host defence peptides (HDPs), exhibit broad-spectrum antimicrobial activity and promote wound healing. Their use as supplements to conventional antibiotics is a current topic of discussion; however, knowledge of their quantities in healthy and compromised tissue is a prerequisite for such discussion. To date, no data concerning HDP quantities in irradiated skin are available.

METHODS

Expression profiles of the genes encoding HDPs, namely human beta-defensin-1 (DEFB1, hBD-1), beta-defensin-2 (DEFB4A, hBD-2), beta-defensin-3 (DEFB103, hBD-3) and S100A7, were assessed in samples of non-irradiated and irradiated neck.

RESULTS

A reduction in the expression of all of the examined genes was observed in irradiated skin when compared with non-irradiated skin (statistically significant in the case of S100A7, P = 0.013). Immunohistochemistry revealed differences in HDP distribution with respect to the epithelial layers.

CONCLUSION

The study demonstrates a significant reduction in HDP gene expression in neck skin as a result of radiotherapy. These findings might represent a starting point for novel treatments of cutaneous infections in irradiated patients, such as topical supplementation of synthetic HDP.

Zosteriform impetigo: Wolf's isotopic response in a cutaneous immunocompromised district

Background:

Impetigo can result from Staphylococcus aureus (S. aureus). Wolf’s isotopic response is the occurrence of a new cutaneous disorder at the site of a previously healed disease. A cutaneous immunocompromised district is an area of skin that is more vulnerable than the rest of the individual’s body.

Purpose:

To describe a man with impetigo localized to a unilateral dermatome and review the clinical features of other patients with zosteriform Staphylococcus aureus cutaneous infection.

Methods:

PubMed was used to search the following terms, separately and in combination: cutaneous, dermatome, dermatomal, district, herpes, immunocompromised, impetigo, infection, isotopic, response, skin, staphylococcal, Staphylococcus aureus, Wolf, zoster, zosteriform. All papers were reviewed and relevant manuscripts, along with their reference citations, were evaluated.

Results:

Crusted, eroded and intact, erythematous papules and nodules acutely presented localized to the mandibular branch of the left trigeminal nerve on the face of a 66-year-old man; he did not recall a prior episode of varicella-zoster virus infection in that area. A bacterial culture isolated methicillin-susceptible S. aureus. Viral cultures and direct fluorescent absorption studies were negative for herpes simplex and herpes zoster virus. All of the lesions resolved after oral treatment with cefdinir. Impetigo and/or furunculosis in a zosteriform distribution have also been described in 3 additional patients. The bacterial culture showed either methicillin-susceptible or methicillin-resistant S. aureus; the skin infection resolved after treatment with oral antibiotics; however one man experienced 2 recurrences in the same area.

Conclusions:

Zosteriform cutaneous staphylococcal impetigo may be an example of Wolf’s isotopic response in a cutaneous immunocompromised district