Summary
Although soluble CD40L (sCD40L, possibly derived from platelets and pro-inflammatory
in vitro) may be implicated in thrombosis and haemostasis, there are little data in peripheral
artery disease (PAD). We hypothesised the following: (a) that sCD40L relates to the
clinical severity of PAD; and (b) that peripheral artery angioplasty acutely raises
sCD40L levels. sCD40L was compared to established platelet markers soluble P selectin,
platelet microparticles and platelet surface expression of CD62 and CD63. We recruited
36 healthy controls, 33 patients with intermittent claudication (IC), and 33 with
symptomatically more severe critical limb is chaemia (CLI), measuring plasma markers
by ELISA and membrane markers by flow cytometry. Eleven patients with CLI subsequently
underwent peripheral artery angioplasty: blood was taken before and 10 minutes after
the intervention. Results show that sCD40L was raised in IC at median 68 (IQR 28–333)
pg/ml and in CLI at 64 (34–282) pg/mL compared to 35 (IQR 28–55) pg/ml in the healthy
controls (p=0.009). Levels were no different between IC and CLI. The same distribution
pattern was present for soluble P selectin, %platelets CD62+ve and CD63+ve. sCD40L
failed to correlate significantly with ABPI (p=0.264), unlike %platelets CD62+ve (p=0.0032)
and CD63+ve (p=0.009). Pre-angioplasty sCD40L level of 72 (35–610) ng/ml rose to 100
ng/ml (IQR=60–237)(p=0.018) post–angioplasty. Plasma sCD40L, in addition to other
platelet indices, is raised in peripheral atherosclerosis and is increased by peripheral
artery angioplasty, although levels seem unrelated to clinical severity. Failure to
correlate with other markers suggest the platelet may not be the sole source of sCD40L,
and that other cells may contribute to plasma levels.
Keywords
Platelets - CD40L - peripheral vascular disease - angioplasty - thrombosis - CD154