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Given a passage, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

To investigate for the first time whether the plasma CXCL16 concentration is altered in coronary artery disease (CAD) patients.', 'Accumulating evidence suggests that the novel chemokine/scavenger receptor CXCL16/SR-PSOX is involved in the development of atherosclerosis and CAD.', 'Using ELISA we assessed the plasma CXCL16 concentration in 40 stable angina pectoris (SAP) patients, 17 unstable angina pectoris/non-ST-elevation myocardial infarction (UAP/non-STEMI) patients, 387 survivors of a first myocardial infarction (MI) and healthy control subjects (44 controls for SAP and UAP/non-STEMI patient groups and 387 controls for post-MI patients).', 'SAP patients exhibited significantly lower median CXCL16 levels (2111 pg/ml) than the corresponding control subjects (2678 pg/ml) (P=0.0012). UAP/non-STEMI patients also appeared to have lower CXCL16 levels (2192 pg/ml) compared with controls (NS). Patients investigated 3 months after MI tended (P=0.07) to have lower CXCL16 levels (2529 pg/ml) than the corresponding controls (2638 pg/ml). There were no significant correlations between CXCL16 levels and different measures of CAD severity determined by quantitative coronary angiography in post-MI patients. Neither patients nor controls exhibited significant correlations between CXCL16 levels and plasma lipoprotein fractions, inflammatory cytokines, C-reactive protein or numbers of inflammatory cells in peripheral blood.
Output:
Is decreased plasma CXCL16/SR-PSOX concentration associated with coronary artery disease?