A preliminary study on the significant value of beta-2-microglobulin over serum creatinine in renal transplant rejection and renal failure

Introduction: Beta-2-microglobulin (beta 2M) is a light chain of HLA class I molecule, which is filtered by glomerulus, reabsorbed and catabolised by proximal tubule. It is one of the markers of transplant rejection. The aim of the present study was to find out the level of beta 2M in acute renal failure (ARF), chronic renal failure (CRF), renal transplant rejection (TR) and renal transplantation stable (TS) cases, and correlation of beta 2M with serum creatinine (SCr) in assessing renal failure. Methods: 23 patients with ARF, 22 patients with CRF, six cases of TR, seven patients with TS, and 28 normal healthy controls were studied within a one-year period. Results: Highest mean value of beta 2M was noted (12.97 +/- 3.83 mu g/ml) in CRF, and all cases had elevated beta 2M of which 81.8 percent of cases had beta 2M above 10 mu g/ml. In ARF, all cases had elevated beta 2M and 78.3 percent patients had a value more than 10 mu g/ml with a mean value of 11.75 +/- 2.09 mu g/ml. TR cases also had elevated beta 2M but 50 percent had mild elevation ( less than 10 mu g/ml) and 50 percent had marked elevation ( more than 10 mu g/ml). 42.8 percent of TS patients also had mild elevation of beta 2M in the range 2.10-3.70 mu g/ml. Interestingly, in normal healthy controls, 21.4 percent of patients had mild elevation of beta 2M of 2.1-2.75 mu g/ml, while 78.6 percent of cases had a normal range of beta 2M ( less than 2 mu g/ml). All normal healthy controls and 71.4 percent of TS cases had normal SCr ( less than 1.4 mg/dL). All cases of CRF and TR cases, and 28.6 percent of TS cases had elevated SCr. 81.8 percent of cases with CRF and 60.9 percent of cases with ARF had a marked rise of serum creatinine above 5 mg/dL. Conclusion: Our study showed that beta 2M is not superior over SCr for renal failure and TR cases, because it is also elevated in 21.4 percent of normal controls and 42.8 percent of TS cases. SCr is a cheaper, simpler and comparatively good test to assess renal failure and TR.