INVERSE CORRELATION OF INTERLEUKIN-6 WITH SOLUBLE INTERLEUKIN-6 RECEPTOR AFTER TRANSPLANTATION OF BONE-MARROW OR PERIPHERAL-BLOOD STEM-CELLS

The relationship between interleukin-6 (IL-6) and the soluble interleu kin-6 receptor (sIL-6R) was analysed in 1481 serum samples of 82 patie nts after bone marrow or peripheral blood cell transplantation. The cy tokine and its soluble receptor were measured on a daily basis startin g at day -3 before and ending at day 21 after transplantation. IL-6 se rum levels increased after transplantation, were at a maximum at day 6 and returned to the baseline level thereafter. The levels of sIL-6R s howed an inverse course with a minimum at day 6. Statistical analysis revealed a strong inverse correlation between IL-6 and sIL-6R with a w eighted Spearman rank correlation coefficient of -0.53 (P < 0.001). IL -6 may play a role in the decrease of sIL-6R either by the direct inhi bitory effect on the expression of the IL-6R gene or by formation of I L-6/sIL-6R complexes followed by their internalization in target cells .