Diurnal variations of C-reactive protein in trait and sickle cell disease patients

Abstract

Sickle cell disease (HbSS) is the most common variant of β-globin gene, resulting from the replacement of glutamic acid by valine at position 6 in the β chain. Under the action of certain factors, such as cold, fever, dehydration, and infections, sickle cell crisis is usually precipitated. The crisis predisposes to aggregation of sickle cells, which may produce vaso-occlusion of capillaries, resulting in pain, swelling, and infarction. In response to inflammation, the liver releases a variety of acute phase proteins. C-reactive protein (CRP) is pentameric hepatocyte protein and is the measure marker of the “acute phase response,” or the formation of plasma proteins in response to an inflammatory stimulus in human. This study is an attempt to document diurnal variations in the level of CRP in sickle cell disease (SCD) patients in steady or crisis state. Saliva samples from SCD, sickle cell trait (SCT), and control subjects were collected continuously over a period of three days. C-reactive protein level was detected using RHELAX CRP Latex kit with the sensitivity of 0.6 mg/dl. When pooled data were subjected for Cosinor rhythmometry, it failed to detect sinusoidality among SCD patients suggesting a constant elevated level of CRP level due to inflammation. However, a statistically significant circadian variation among control and SCT in CRP levels was discerned. Result suggests that although the level of CRP in SCT is comparatively higher than the normal individuals, the CRP contents significantly fluctuate in the absence of chronic inflammation among traits. The rhythm-adjusted mean was found to be significantly higher in SCD (p ≤ 0.005) patients when compared to control and trait subjects. A constant higher level of CRP can also be an indicator of future cardiac complications in SCD patients.