Related Experiment Video
Updated: Jun 4, 2026

Ex Vivo Infection of Human Lymphoid Tissue and Female Genital Mucosa with Human Immunodeficiency Virus 1 and Histoculture
Published on: October 12, 2018
Enfuvirtide injection site reactions: a clinical and histopathological appraisal
Brian J Wallace1, King-Bing Tan, Sarah L Pett
1Department of Dermatology, St Vincent's Hospital, New South Wales, Australia. bwallace@med.usyd.edu.au
Background/Objectives:
Enfuvirtide was the first of a new class of antiretroviral agents termed 'fusion inhibitors' used for the treatment of HIV-1 infection. Enfuvirtide is administered subcutaneously and injection site reactions (ISR) are commonplace (98%). The aim of this study was to analyse in detail the histopathological changes associated with striking ISR seen in four patients.
Methods:
Biopsies were obtained at various times post-injection and were reviewed histologically. The changes in epidermal, dermal and subcutaneous connective tissue and the presence and nature of the inflammatory cellular infiltrate were noted. An immunohistochemical assessment was undertaken.
Results:
All biopsy specimens demonstrated striking changes in the dermal connective tissue. Alteration in collagen was the most prominent feature and resembled a morphoea/scleroderma-like process. These changes persisted well beyond cessation of enfuvirtide (>1 year). The relative populations of dermal dendritic cells (DDC) (types 1 (Factor XIIIa) and 2 (CD34+)) were analysed and a reciprocal relationship between DDC subpopulations was observed akin to that observed in other sclerosing and fibrosing conditions.
Conclusion:
This study details histopathological changes associated with enfuvirtide ISR. We postulate that changes in DDC populations may contribute to the pathogenesis of the sclerotic process observed with enfuvirtide ISR.
Related Concept Videos
Hypersensitivity Reactions: Cytolytic Reactions
Inhibitors of Viral Protein Synthesis
Hypersensitivity Reactions: Immune-Complex Reactions
Viral Hepatitis I: Introduction
Encephalitis ll: Pathophysiology
Drug Toxicity: Allergic Reactions

