Platelet count and Interleukin 6 Gene polymorphism in healthy subjects
1 Unitat de Diabetologia, Endocrinologia i Nutricio, University Hospital of Girona "Dr Josep Trueta", Girona, Spain
2 Internal Medicine and Unitat d'Endocrinologia, Hospital of Tarragona "Joan XXIII". Facultat Medicina, Universitat Rovira i Virgili, Tarragona, Spain
BMC Medical Genetics 2001, 2:6 doi:10.1186/1471-2350-2-6Published: 1 June 2001
Interleukin 6 (IL-6) is thought to play important roles in the development of reactive thrombocytosis caused by inflammation by its stimulatory effect on megakaryocytopoiesis. A G/C polymorphism of the IL-6 gene at position -174 has been found to be associated to different transcription rates. Specifically, subjects with the CC genotype showed lower plasma IL-6 levels compared with GC or GG subjects. Given this difference in transcription rates of IL-6 we speculated on different platelet count according to this IL-6 polymorphism.
The G/C polymorphism of the IL-6 gene at position -174, serum IL-6 concentration and platelet count were prospectively analyzed in 59 (25 women) consecutive healthy subjects.
Subjects who were homozygotes for the C allele at position -174 of the IL-6 gene (Sfa NI genotype) showed significantly lower platelet count than carriers of the G allele, despite similar age, sex, body mass index and proportion of smokers (205400 ± 44088 vs 239818 ± 60194, p = 0.047). This was in parallel to differences in peripheral white blood cell count (5807 ± 1671 vs 6867 ± 1192 × 109/ml, p = 0.01).
This is the first description, to our knowledge, of a genetical influence on basal platelet counts, which appears to be partially dependent on a polymorphism of the IL-6 gene, even in the absence of inflammation.