Understanding how human skin reacts to tick bites

Investigating the Human Immune Response to Ixodes Scapularis Tick Bites

This study is testing how healthy adults' skin reacts to bites from certain ticks to better understand the immune response and help develop ways to resist tick bites.

Quick facts

• Phase: Phase1; Phase2
• Study type: Interventional
• Enrollment: 60 (estimated)
• Ages: 18 Years to 99 Years
• Sex: All
• Sponsor: National Institutes of Health Clinical Center (CC) (NIH)
• Locations: 1 site (Bethesda, Maryland)
• Trial ID: NCT05036707 on ClinicalTrials.gov

What this trial studies

This study aims to investigate the immune response of healthy adults to bites from Ixodes scapularis ticks, which are known vectors for several tick-borne diseases, including Lyme disease. Participants will undergo skin biopsies and have laboratory-bred ticks placed on their skin to monitor local and systemic immune responses. The study will help develop a model for acquired tick resistance and assess the body's reaction to tick saliva. It is a prospective, non-randomized, single-center study conducted at the NIH Clinical Center.

Who should consider this trial

Good fit: Ideal candidates for this study are healthy adults aged 18 years and older with no history of tick-borne diseases or tick bites.

Not a fit: Patients with a known history of tick-borne diseases or previous tick bite exposure may not benefit from this study.

Why it matters

Potential benefit: If successful, this research could lead to the development of effective vaccines against tick-borne diseases.

How similar studies have performed: While there have been studies on tick-borne diseases, this specific approach to understanding human immune response to tick bites is relatively novel.

Eligibility criteria

* INCLUSION CRITERIA:

In order to be eligible to participate in this study, an individual must meet all of the following criteria:

1. Stated willingness to comply with all study procedures and availability for the duration of the study.
2. Age 18 years or older.
3. In good general health as evidenced by medical history.
4. No history of TBD.
5. No known tick bite.
6. Serum IgE level within Clinical Center Department of Laboratory Medicine normal range.

   https://ccinternal2.cc.nih.gov/LTGRA/UL/public\_labtest\_detail.aspx?next\_flg=Y\&test\_id=4731\&id\_order=53
7. Serum tryptase level within Clinical Center Department of Laboratory Medicine normal range.

   https://ccinternal2.cc.nih.gov/LTGRA/UL/public\_labtest\_detail.aspx?next\_flg=Y\&test\_id=1157\&id\_order=1
8. For participants of child-bearing potential: use of effective contraception for at least 1 month prior to tick placement, and agreement to use such a method during study participation and for an additional 3 months after the removal of the last ticks. Types of contraception include abstinence, surgical methods (sterilization, implants, intrauterine device, partner with vasectomy), hormonal methods (birth control pill, patch, ring, injection), or barrier methods (diaphragm plus spermicide, male condom plus spermicide)
9. For males of reproductive potential: use of condoms or other methods to ensure effective contraception with partner.
10. Agree to not participate in other clinical studies requiring investigational interventions for the duration of the study.
11. Minimum hemoglobin of 13.0 g/dL for males and 12 g/dL for females

EXCLUSION CRITERIA:

An individual who meets any of the following criteria will be excluded from participation in this study:

1. History of forming large thick scars (keloids) after skin injuries.
2. History of excessive bleeding after cuts or procedures.
3. History of taking anticoagulants in the past 28 days.
4. History of allergic reaction to lidocaine.
5. History of allergic reaction to tape, adhesive bandages, or dressings.
6. Inability to maintain the dressing for any reason.
7. Pregnancy or lactation.
8. Treatment with another investigational drug or other intervention within the past 30 days.
9. Oral or intravenous (IV) steroids in the 2 weeks prior to each tick placement procedure (topical, nasal, inhaled, intra-articular, and replacement doses of steroids are not exclusions).
10. History of reactions to mammalian meat, IgE- mediated food allergies, urticaria or anaphylaxis. Mild pollen-food allergy syndrome is not an exclusion.
11. History of systemic allergic reaction to venom (bee, wasps and other Hymenoptera stings).
12. History of clinically significant drug allergies.
13. History of moderate to severe atopy asthma, atopic dermatitis, allergic rhinitis.
14. Active severe skin disease, uncontrolled diabetes, cancer other than non-melanoma skin cancers, autoimmune disease requiring immunosuppressive therapy, or history of human immunodeficiency virus (HIV), chronic viral hepatitis, or syphilis.
15. Refusal to allow storage of samples and data for future usage..
16. Any other condition that, in the opinion of the investigator, would make the patient unsuitable for enrollment or could interfere with the patient participating in and completing the study.

Exclusion of Select Populations:

Children:

Children are excluded from this protocol as there is no direct benefit to the participants, the risk from the skin biopsies is small but above minimal, the procedure is invasive and can be stressful for children, and there is concern over their ability to maintain the LeFlap dressing.

Pregnant and breastfeeding women:

Pregnant and breastfeeding women are excluded from trial participation as there is no direct benefit to the participants.

Adults who lack capacity to consent:

Adults lacking decision-making capacity to provide informed consent are excluded at screening as there is no direct benefit to the participants.

Enrolled participants who permanently lose the ability to consent during participation will be monitored for safety but will have no additional research procedures performed.

Where this trial is running

Bethesda, Maryland

• National Institutes of Health Clinical Center — Bethesda, Maryland, United States (Recruiting)

Study contacts

• Principal investigator: Adriana R Marques, M.D. — National Institute of Allergy and Infectious Diseases (NIAID)
• Study coordinator: Siu-Ping Ng, R.N.

Conditions Tick-borne Diseases; Tick Resistance; Lyme Disease; Tick Immunity; Tick-borne diseases; Vaccines