Functional polymorphisms of interleukin 4 and interleukin 10 may predict evolution and functional outcome of an ischaemic stroke

Background and purpose: Inflammatory cytokines are involved in the systemic inflammation, which precedes an ischaemic stroke (IS), and also participate into brain ischaemia-reperfusion injury. We sought to investigate whether functional polymorphisms of two anti-inflammatory molecules, interleukin (IL)4-589C>T and IL10-1082G>A, might be associated with the occurrence, clinical course and functional outcome of an acute IS.

Methods: We genotyped 290 subjects (145 consecutive IS cases and 145 age- and sex-matched controls) using a real-time PCR technology, prototypically designed for these mutations. Patients were evaluated with the Scandinavian Stroke Scale, and definitions of severity grouping and stroke progression were applied based on international agreements. Follow-up on months 1, 3, and 6 included registration of disease relapses, deaths and functional outcome measured by the Barthel Index.

Results: IL4-589 and IL10-1082 genotypes did not significantly differ between cases and controls. The presence of IL4-589 T allele was associated with total IS recurrences [OR (95% CI) = 3.34 (1.18-9.45)], adjusted for age, sex and conventional risk factors. IL10-1082 GG genotype was found to significantly predict early stroke progression [OR (95% CI) = 3.72 (1.28-10.76)] and functional outcome by months 1 and 3 [OR (95% CI) = 5.03 (1.15-21.94) and 5.84 (1.07-31.85), respectively], after further corrections for stroke severity and TOAST categories.

Conclusions: The functional IL4-589C>T and IL10-1082G>A polymorphisms seem not to be associated with occurrence of an IS, but may predict IS relapses, progressing strokes and functional outcome, independently of conventional risk factors. Our results merit further confirmation in future studies.