Effect of Vitamin A Supplementation on Immune Responses in Human Neonates

Condition(s) targeted: Vitamin A Deficiency

Intervention: Vitamin A (retinyl palmitate). (Dietary Supplement)

Phase: Phase 2

Status: Not yet recruiting

Sponsored by: London School of Hygiene and Tropical Medicine

Official(s) and/or principal investigator(s):
Suzanna LR McDonald, BSc (Hons) MSc PhD, Principal Investigator, Affiliation: London School of Hygiene and Tropical Medicine

Overall contact:
Suzanna LR McDonald, BSc (Hons) MSc PhD, Phone: (+220) 4495442/6, Ext: 5016, Email: smcdonald@mrc.gm

Vitamin A supplementation (VAS) significantly reduces all-cause mortality when given after 6 months of age, but has a null or detrimental effect when given between 1-5 months. Studies of neonatal VAS (NNVAS) have produced conflicting findings. These age-pattern variations might result from immunological interactions between VAS and vaccines. The potential efficacy of NNVAS is being retested in 3 large new intervention trials with mortality as endpoint. Complementary mechanistic studies in animals and in human infants in The Gambia (this proposal) and Bangladesh have been commissioned to run in parallel.

The investigators will use a 2-arm double blind RCT to test whether NNVAS modulates the early ontogeny of human immune development. Neonates, recruited through a peri-urban clinic in The Gambia, will receive either 50,000 International Units (IU) VAS orally within 48 hours of birth (intervention group, n=100) or a placebo (control group, n=100). Male and female neonates will be randomized separately at enrolment for later analyses by sex. All infants will be followed up from birth to age 1 year. A broad panel of immunological outcomes will examine whether NNVAS: a). normalises thymic development (thymic index by ultrasound); b). skews mycobacterial and recall antigen responses towards a Th2 profile; c). diminishes Th1 and Th17 reactivity to mycobacterial and recall antigens; d). diminishes the tuberculin skin test (TST) response; e). causes increased innate immune reactivity; f). increases the frequency of circulating regulatory T cells (Tregs) expressing gut homing receptors; g). enhances B cell immune responses after routine vaccination (increase of B cell numbers and activation status); h). increases circulating IgA in mucosal immune compartment, especially oral polio vaccine (OPV) specific IgA post-vaccination; i). decreases bacterial translocation, by improving mucosal barrier function; and j). decreases markers of infection or inflammation. Growth and morbidity will also be assessed.

Official title: A Randomized Controlled Trial in Human Neonates to Determine the Effect of Vitamin A Supplementation on Immune Responses

Study design: Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)

Primary outcome: Frequency of circulating Tregs expressing gut homing receptors in infant participants.

Secondary outcome:

Difference in Thymus size in infant participants

Difference in B cell immune responses after routine vaccination in infant participants

Improved mucosal barrier function in infant participants

Minimum age: N/A. Maximum age: 48 Hours. Gender(s): Both.

Criteria:

Inclusion Criteria:

- singleton birth,

- birth weight ≥1,500g,

- mother over 18 years willing to participate and residency within the study area.

- Birth vaccinations and vitamin A supplement must be administered within 48 hours of

birth.

Exclusion Criteria:

- Infants having a congenital disease,

- a serious infection at birth

- an inability to feed (initially assessed by the lack of the suck reflex),

- mothers who are seriously ill at time of enrolment (defined as bed bound for more

than 24 hours),

- mother participating in other studies,

- mothers who are HIV positive.

Suzanna LR McDonald, BSc (Hons) MSc PhD, Phone: (+220) 4495442/6, Ext: 5016, Email: smcdonald@mrc.gm

Medical Research Council, The Gambia Unit, Fajara, Gambia

Starting date: November 2011
Last updated: November 17, 2011