Monoclonal gammopathy (MG) encompasses a diverse group of disorders characterized by the secretion of monoclonal immunoglobulins or their light-chain components. The incidence of multiple myeloma (MM) in South Korea is rapidly increasing, and it is important to be aware of its initial clinical presentations and the most efficient laboratory algorithms for early detection. Serum protein electrophoresis (SPE) and urine protein electrophoresis (UPE) are the primary screening tests for patients with clinically suspected MM or amyloid light-chain amyloidosis; these tests are reimbursed in South Korea. We reviewed clinical studies that applied national and international guidelines to evaluate test panels for early detection of MGs, including MM. The serum free light chain (sFLC) with SPE panel is recommended for the initial work up for diagnosis of MGs. In the case of a normal SPE, sFLC should be measured subsequently, so as not to miss the presence of M-protein. Use of this screening panel avoids medical expenses related to delayed diagnosis. Guidelines and recommendations suggest that no single method (SPE, serum immunofixation electrophoresis, sFLC, or UPE) should be used to exclude a diagnosis of MM. We believe that a screening test panel comprising SPE plus sFLC will increase the rate of early and accurate diagnosis of MM and related disorders.

Aims Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) regulate matrix remodelling in the heart and play a pivotal role in myocardial dysfunction immediately following ischaemia-reperfusion injury ex vivo in rats. We investigated the changes in MMPs and TIMPs in acute myocardial ischaemiareperfusion injury in humans. Methods and results Fifteen patients with stable angina undergoing coronary artery bypass graft surgery with cardiopulmonary bypass were enrolled. Left ventricular stroke work index was monitored prior to bypass and for 24 h following reperfusion. Left atrial biopsy samples were obtained at the start of bypass before cardioplegia and within 10 min after removal of the aortic cross-clamp. Plasma samples were collected from the radial artery and coronary sinus 1, 5, and 10 min following removal of the cross-clamp. In cardiac biopsies there was a marked increase in 72 kDa MMP-2 and 92 kDa MMP-9 activities, and a decrease in TIMP-1 upon reperfusion. Increased MMP activity correlated positively with cross-clamp duration and inversely with cardiac mechanical function 3 h following reperfusion. TIMP-1 correlated inversely with cross-clamp time and positively with cardiac mechanical function. Plasma samples revealed a significant increase in both 92 kDa MMP-9 and 64 kDa MMP-2 activities 1 min following removal of cross-clamp. Conclusion Reperfusion following cardioplegia activates MMPs in the myocardium and plasma of patients undergoing coronary artery bypass grafting. This is the first correlation of MMP myocardial activity with cardiac function in humans. The early increase in MMP activity produces a proteolytic environment that may contribute to myocardial stunning injury in humans.