Objective: IGF-1 stimulates growth, development and function of lymphocytes. The aim of this study was to examine whether functional variants of the IGF-1 gene are associated with absolute lymphocyte subset counts in neonates. Study design and measurements: This study was embedded in the Generation R Study, a prospective cohort study from foetal life onwards. A polymorphism in the IGF-1 promoter region was genotyped in cord blood DNA. Lymphocytes (T, B and NK) and T lymphocyte subsets (helper, cytotoxic, naïve and memory) in cord blood were immunophenotyped in 380 neonates by six-colour flow cytometry. Results: In total, 39% of the neonates were homozygous for the 192-bp allele (wild-type), 48% were heterozygous and 13% were noncarrier. No differences in absolute lymphocyte and T lymphocyte subset counts were observed between the 192-bp allele heterozygous and homozygous groups. In noncarriers, we found 15% lower T lymphocyte (P = 0.03), 22% lower B lymphocyte (P = 0.04) and 10% lower NK lymphocyte counts (P = 0.36) than in the 192-bp allele homozygous group. Analyses of T lymphocyte subsets showed 16% lower helper T lymphocyte counts (P = 0.01) in noncarriers. No significant differences were found for cytotoxic, naïve and memory T lymphocyte counts. All associations were adjusted for gravidity, mode of delivery, gestational age, birth weight, gender and 1- and 5- min Apgar scores. Conclusions: Our study showed associations between this IGF-1 promoter region polymorphism and absolute lymphocyte subset counts in neonates. These results should be regarded as hypothesis generating until they have been replicated in other studies.

Additional Metadata
Persistent URL dx.doi.org/10.1111/j.1365-2265.2008.03294.x, hdl.handle.net/1765/25096
Journal Clinical Endocrinology
Duijts, L, Bakker-Jonges, L.E, Mook-Kanamori, D.O, Labout, J.A.M, Hofman, A, Tikka-Kleemola, P, … Jaddoe, V.W.V. (2009). Variation in the IGF-1 gene is associated with lymphocyte subset counts in neonates: The Generation R Study. Clinical Endocrinology, 70(1), 53–59. doi:10.1111/j.1365-2265.2008.03294.x