Soluble CD40L Is a Useful Marker to Predict Future Strokes in Patients With Minor Stroke and Transient Ischemic Attack
Background and Purpose—Elevated soluble CD40 ligand (sCD40L) was shown to be related to cardiovascular events, but the role of sCD40L in predicting recurrent stroke remains unclear.
Methods—Baseline sCD40L levels were measured in 3044 consecutive patients with acute minor stroke and transient ischemic attack, who had previously been enrolled in the Clopidogrel in High-Risk Patients With Acute Nondisabling Cerebrovascular Events (CHANCE) trial. Cox proportional-hazards model was used to assess the association of sCD40L with recurrent stroke.
Results—Patients in the top tertile of sCD40L levels had increased risk of recurrent stroke comparing with those in the bottom tertile, after adjusted for conventional confounding factors (hazard ratio, 1.49; 95% confidence interval, 1.11–2.00; P=0.008). The patients with elevated levels of both sCD40L and high-sensitive C-reactive protein also had increased risk of recurrent stroke (hazard ratio, 1.81; 95% confidence interval, 1.23–2.68; P=0.003).
Conclusions—Elevated sCD40L levels independently predict recurrent stroke in patients with minor stroke and transient ischemic attack.
CD40 ligand (CD40L) plays a role in atherosclerotic plaque instability.1 Soluble CD40L (sCD40L) was released from activated platelet and shown to be a predictor of first2 and subsequent cardiovascular events.3 Recently, a genetic study indicated that CD40-1C>T polymorphisms was associated with the risk of reocclusion after successful fibrinolytic therapy in patients with stroke,4 suggesting that sCD40L might be associated with prognosis of stroke. However, the role of sCD40L in predicting recurrent stroke remained unclear.
The Clopidogrel in High-Risk Patients With Acute Nondisabling Cerebrovascular Events (CHANCE) trial compared efficacy of clopidogrel plus aspirin and aspirin alone in the patients with acute minor stroke and transient ischemic attack.5 The cohort of CHANCE trial provided an opportunity to investigate whether sCD40L levels predict recurrent stroke.
Totally 5170 patients within 24 hours after acute minor stroke or transient ischemic attack were randomized to receive either clopidogrel plus aspirin or aspirin alone.5 Serum samples were collected 24±12 hours after randomization. The primary outcome was stroke within 90-day follow-up period. The CHANCE protocol was approved by the ethics committee at each study center.
Measurements of Biomarkers
sCD40L levels were determined via an ELISA kit (catalogue number BMS239; eBioscience, Vienna, Austria). High-sensitive C-reactive protein (hsCRP) was measured in the clinical laboratory in Tiantan hospital. All measurements were performed by laboratory personnel blinded to the study status.
Proportions were used for categorical variables. Medians with interquartile ranges were used for continuous variables because of skewed distribution. Categorical and continuous variables were compared with the χ2 statistics and Kruskal–Wallis test, respectively. The relationship of sCD40L and outcome was investigated with Cox proportional-hazards model. A 2-sided P value of <0.05 was considered to be statistically significant.
There were 73 (64%) prespecified centers voluntarily participated in the biomarker substudy, enrolling 3044 consecutive patients.
Characteristics of patients are shown in Table I in the online-only Data Supplement. Patients in the top tertile of sCD40L levels were younger, likely had history of hypercholesterolemia, and higher baseline levels of low-density lipoprotein-cholesterol, triglycerides, hsCRP, and leukocyte count.
sCD40L and Recurrence of Stroke
Patients in the top tertile of sCD40L levels had increased risk of recurrent stroke (Figure I in the online-only Data Supplement). The increased risk remained after adjusted for other confounding factors (Table). The hazard ratios increased with rising tertiles (Table). Similar results were found when sCD40L was assessed as a continuous variable (Table). Besides sCD40L, the factors of age, history of hypertension and diabetes mellitus, baseline National Institutes of Health Stroke Scale, baseline low-density lipoprotein-cholesterol levels, and dual antiplatelet therapy also predicted subsequent strokes (Figure II in the online-only Data Supplement).
sCD40L was interacted with hsCRP in its effect on recurrent stroke (P=0.01). Patients were subsequently divided into 6 groups according to tertiles of sCD40L levels and concentrations of hsCRP either >3 or ≤3 mg/L. The patients with elevated levels of both sCD40L and hsCRP also had increased risk of recurrent stroke (hazard ratio, 1.81; 95% confidence interval, 1.23–2.68; P=0.003; Figure III in the online-only Data Supplement).
Although the role of sCD40L in predicting cardiovascular events has been well elucidated before, the association between sCD40L and stroke was still unclear.6,7 One potential reason for this apparent discrepancy may relate to the use of combined vascular events as the end point, which would make the individual association of sCD40L with stroke not as apparent. On the contrary, most of these researches have focused on the first stroke.
sCD40L played a role in atherosclerotic plaque instability1 and platelet activation.8 Our results showed sCD40L predicted recurrent stroke, which indicated that sCD40L may represent another approach other than conventional risk factors to stratify the risk of recurrent stroke. Furthermore, it has been noted well that ischemic events still occurred in some patients, despite sustained standard secondary preventive therapy, indicating other therapeutic strategies should be implemented. Our findings might suggest sCD40L as a target for studies targeting the inflammatory cascade for stroke prevention. hsCRP was another inflammatory marker associated with prognosis of stroke9; however, power was limited to find an independent effect of the combination of these 2 biomarkers because of overlapped confidence intervals in the current study.
Our study had some limitations. First, only baseline levels of sCD40L were obtained and the fluctuation of sCD40L could not be completely eliminated. Second, we did not adjust statin dose because of lack of the data, which was shown to be associated with stroke risk.10 Third, the data on stroke subtypes were absent. These should be considered in the further study.
In conclusion, this substudy of CHANCE trial suggested that baseline sCD40L could serve as a prognostic factor of future recurrent stroke in patients with acute minor ischemic stroke and transient ischemic attack. Analysis of this biomarker may represent another approach to stratify the risk of recurrent stroke.
Sources of Funding
This study was, in part, supported by a grant (No. 81200844 to Dr Li) from The National Natural Science Foundation of China, a grant (No.2014ZZ-10 to Dr Li) from Beijing Postdoctoral Working Funding, grants (Nos 2008ZX09312-008, 2012ZX09303, and 200902004 to Dr Yongjun Wang; No. 2011BAI08B02 to Dr Yilong Wang) from the Ministry of Science and Technology of the People’s Republic of China, a grant (No. D131100005313003 to Dr Yongjun Wang) from Beijing Biobank of Cerebral Vascular Disease, a grant (No. 81471211 to Dr Yongjun Wang) from the National Natural Science Foundation of China.
The online-only Data Supplement is available with this article at http://stroke.ahajournals.org/lookup/suppl/doi:10.1161/STROKEAHA.115.008685/-/DC1.
- Received January 12, 2014.
- Revision received April 13, 2015.
- Accepted April 21, 2015.
- © 2015 American Heart Association, Inc.
- Schönbeck U,
- Libby P.
- Novo S,
- Basili S,
- Tantillo R,
- Falco A,
- Davì V,
- Novo G,
- et al
- del Río-Espínola A,
- Fernández-Cadenas I,
- Rubiera M,
- Quintana M,
- Domingues-Montanari S,
- Mendióroz M,
- et al
- Ferro D,
- Loffredo L,
- Polimeni L,
- Fimognari F,
- Villari P,
- Pignatelli P,
- et al
- Lip GY,
- Patel JV,
- Hughes E,
- Hart RG.
- Segal HC,
- Burgess AI,
- Poole DL,
- Mehta Z,
- Silver LE,
- Rothwell PM.