Markers of Laminin and Type I Collagen in Sera of Patients with Sickle Cell Disease

Sickle cell disease commonly causes avascular necrosis of ht skeletal system. Repeated episodes of sickling of the erythrocytes lead to repeated episodes of vaso-occlusion which affects the bone, spleen and other organs. Recently developed assay methods, which are based on the measurement of some of the fragments of procollagen or collagen molecule or parts of noncollagenous basement proteins are used to assess the connective tissue metabolism in patients with this disorder. The levels of carboxyterminal propeptide of type I procollagen, carboxyterminal telopeptide of type I collagen, and fragment P1 of laminin (PICP, ICTP, and laminin P1 respectively) in serum were measured by radioimmunoassay in patients with sickle cell disease. The concentrations of PICP, ICTP (both ug/l), and laminin (U/ml) were statistically significant in the study group than in the control group (p < 0.001, 0.003, and 0.02, respectively). The upper limits of the reference ranges (i.e. mean ± 2 SD of control) for PICP, ICTP, and laminin were exceeded by 7/20 (35%), 8/20 (40%), and 14/20 (70%) of patients respectively. The biomarkers of type I collagen (PICP and ICTP) had positive correlation. There was no correlation between serum laminin and PICP or ICTP levels in the patient group. Conclusions: These findings indicate that serum markers of type I collagen and laminin may be useful as valuable non-invasive indices of extracellular matrix in bone, spleen or other tissues in sickle cell disease.