Pretransplant β2-Microglobulin Is Associated with the Risk of Acute Graft-versus-Host-Disease after Allogeneic Hematopoietic Cell Transplant

The risk of acute graft-versus-host disease (aGVHD) can be reliably estimated by the hematopoietic cell transplantation-specific comorbidity index (HCT-CI), which can be further refined by the incorporation of pre-hematopoietic cell transplantation (HCT) serum levels of inflammatory biomarkers such as ferritin and albumin. β2-Microglobulin (β2-m) is a key component of the MHC class I complex, which is independently associated with mortality and frailty in the general population. We took advantage of our institutional protocol that includes measurement of pre-HCT β2-m serum levels in the most patients to investigate whether pre-transplant β2-m levels were associated with the risk of aGVHD. One hundred three consecutive patients submitted to allogeneic HCT, of which 26 developed grades II to IV aGVHD, were included in the analysis. β2-m was significantly associated with age and HCT-CI. Higher levels of β2-m were observed in patients who developed aGVHD (P = .008). In the multivariate Cox regression model, β2-m and HCT-CI remained independently associated with the risk of developing aGVHD. In conclusion, the association between β2-m and the occurrence of aGVHD suggests that the measurement of this protein before HCT might represent an additional element for risk stratification of aGVHD.