Biological Markers of Inflammation and Carpal Tunnel Syndrome in Dialysis Patients

Dr. Giuseppe Curatola, Divisione di Nefrologia e CNR, Centro di Fisiologia Clinica, via Sbarre Inferiori, I-89131 Reggio Calabria (Italy) Fig. 1. Acute-phase reactants in the three study groups. Data are mean ± SD. ES = Group with carpal tunnel syndrome; ■ = control group; ¤ = normal subjects, a α‚-Antitrypsin. b c3⁄8Macroglobulin. c C-reative protein, d αrAcid glycoprotein. Blood sampling was performed immediately before dialysis. Acute-phase reactants were measured by using a commercially available nephelometric method (Ben-ring). To evaluate the biological variability of these measurements, blood sampling was repeated in all cases after an interval of 1 month. As shown in figure 1, αrantitrypsin and o1⁄8-macro-globulin were significantly higher in carpal tunnel patients than in the control group. C-reactive protein showed a similar tendency (p = 0.14). αrAcid glycoprotein was increased by the same extent in the two dialysis groups in comparison with healthy subjects. Dear Sir, Carpal tunnel syndrome is a frequent and disabling complication of long-term dialysis. This syndrome is considered secondary to the deposition of ß2-microglob-ulin in the carpal tunnel synovia and tendons, a process which is favored by the retention of this substance. ß2Microglobulin accumulation may depend on various factors such as poor dialysis removal, enhanced generation rate promoted by subclinical inflammatory processes [1] and/or reduced metabolic degradation. The study of acute-phase reactants in carpal tunnel syndrome is of interest because some of these substances, in addition of being mediators of inflammation, display antiproteolytic activity and in this way may reduce ß2-microglobulin catabolism. We have, therefore, compared the plasma levels of 4 well-characterized acute-phase reactants (αrantitrypsin, α2-macroglobulin, αΓacid gly-coprotein and C-reactive protein) in dialysis patients with and without this syndrome. Nine hemodialysis patients with well-documented carpal tunnel syndrome [abnormal electromyographic (EMG) studies and/or clinical improvement after surgical decompression] and 9 hemodialysis patients without carpal tunnel syndrome (no clinical symptoms and negative