A Comparative Study to Assess Efficacy of Intralesional MMR (Measles, Mumps, Rubella) Vaccine and Intralesional Vitamin D3 in Treatment of Warts

INTRODUCTION Warts are common skin conditions resulting from infection of keratinocytes by human papillomavirus (HPV). After infection of the basal layer, there is clonal proliferation leading to epidermal thickening and hyperkeratinization and eventually results in a visible wart. HPVs are ubiquitous, epitheliotropic non-enveloped small double-stranded DNA viruses. Over 150 types of HPVs have been identified. Among them verruca vulgaris are usually caused by HPV types 1, 2, 4, 27 or 57, and plane warts by HPV types 3 or 10.

Cutaneous warts occur in 7% to 10% of the general population, with a maximum incidence between the ages of 12 and 16 years. In children, clearance can occur after only a few months, with 50% at 1 year and about 65%-78% by 2 years. The rate of clearance is influenced by factors like virus strain, host immune status, extent and duration of warts. The transmission of warts occurs from direct contact or indirectly via fomites.

There are multiple destructive, antiproliferative and antiviral agents in treatment of warts. Other modalities include hypnotherapy, acupuncture, local hyperthermia, therapeutic vaccination and combinations of the previous agents. Destructive therapies usually come with many adverse effects hence immunotherapy is becoming more popular, especially in the treatment of refractory cutaneous and genital warts. These include various topical, intralesional (IL) and systemic agents. IL Measles, Mumps, rubella (MMR) and IL vitamin D3 are examples of immunotherapeutic agents.

Immunotherapy is defined as a type of biological therapy that uses substances to stimulate or suppress the immune system to help the body fight cancer, infection, and other diseases. Immunotherapy can affect the immune system in general or can be cell-specific.

Immunotherapy is believed to induce a strong nonspecific pro-inflammatory signal and attract the antigen-presenting cells. This is associated with the release of cytokines such as IL-2, IL-8, IL-12, IL-I8, tumor necrosis factor-α, and interferon-γ. This then promotes a Th1 cytokine response which leads to the activation of delayed-type hypersensitivity reaction leading to the eradication of the HPV-infected cells. Furthermore, the trauma of the injection may also cause a resolution in previously sensitized individuals. Vitamin D3 is also claimed to regulate epidermal cell differentiation and proliferation and may modulate cytokine production through its action upon vitamin D receptors (VDRs). Since IL antigen immunotherapy enhances recognition of the virus by the immune system it causes clearance of both treated and untreated lesions and helps to prevent future clinical infection through induction of long-term acquired immunity to HPV.