Association of cytokine polymorphic inheritance and in vitro cytokine production in anti-CD3/CD28-stimulated peripheral blood lymphocytes

Background. Genetic variations in cytokine genes are thought to regulate cy tokine protein production. However, studies using T cell mitogens have not always demonstrated a significant relationship between cytokine polymorphis ms and in vitro protein production. Furthermore, the functional consequence of a polymorphism at position -330 in the IL-2 gene has not been described . We associated in vitro protein production with cytokine gene polymorphic genotypes after costimulation of cultured peripheral blood lymphocytes. Methods. PBL were isolated from forty healthy volunteers. Cytokine protein production was assessed by enzyme-linked immunosorbent assay. Polymorphisms in interleukin- (IL) 2, IL-6, IL-10, tumor necrosis factor (TNF-alpha), tu mor growth factor (TGF-beta), and interferon (IFN-gamma) were determined by polymerase chain reaction (PCR). Results. Statistical difference between protein production and cytokine pol ymorphic variants in the IL-10, IFN-gamma, and TNF-alpha genes was not evid ent after 48-hour stimulation with concanavalin-A. In contrast, after anti- CD3/CD28 stimulation significant differences (P <0.05) were found among hig h and low producers for IL-2, IL-6, and among high, intermediate, and low p roducers for IFN-gamma, and IL-10. Augmented levels of IL-2 in individuals that were homozygous for the polymorphic IL-2 allele were due to an early a nd sustained enhancement of IL-2 production. No association was found among TNF-alpha and TGF-beta genotypes and protein production. Conclusion. Polymorphisms in IL-2, IL-6, IL-10, and IFN-gamma genes are ass ociated with their protein production after anti-CD3/CD28 stimulation. The profound effect of the IL-2 gene polymorphism in homozygous individuals may serve as a marker for those that could mount the most vigorous allo- or au toimmune responses, or perhaps become tolerant more easily.