['To search for evidence of immune activation in idiopathic preterm term labour by measuring the soluble markers of T cell activation, CD8 (sCD8) and interleukin-2 receptor (sIL2R).', 'Serum sCD8 and sIL-2R were measured by commercial ELISA in subjects undergoing idiopathic preterm labour (PTL; n = 15) and normal term labour (TL; n = 17). Two gestationally equivalent non-labouring groups were also included representing preterm (PTC; n = 10) and term (TC; n = 10) controls. Possible delayed responses in soluble activation markers were monitored in blood samples taken 48 h after delivery in both labouring groups (PTLp; n = 9: TLp; n = 9).', '(1) Excluding the 48 h postpartum samples, no statistically significant differences were revealed following a Kruskall-Wallis analysis of variance (ANOVA) for levels of sIL-2R (P = 0.093) and sCD8 (P = 0.098). Including the postpartum samples, however, gave statistically significant differences for each (sIL-2R: P = 0.033; sCD8: P = 0.006). (2) No statistically significant difference was revealed by direct comparison of the two labouring groups alone (Wilcoxon-Mann-Whitney test: P > 0.05). (3) Significantly lower levels of sCD8 were found in the PTL subgroup which had histological evidence of inflammation (Wilcoxon-Mann-Whitney: P = 0.003).'] Are maternal levels of serum-soluble CD8 and IL-2R significantly elevated in idiopathic preterm labour?