BACKGROUND: Human leukocyte antigen (HLA) class I antigens, are glycoproteins expressed on the cell surface and are also secreted (sHLA) into the surrounding fluids. This study investigates whether pulmonary allograft rejection is associated with an increased amount of sHLA class I in the bronchoalveolar lavage (BAL) fluid. METHODS: Enzyme-linked immunosorbant assays were used to measure sHLA class I levels in BAL samples from 66 lung transplant recipients. RESULTS: Analysis of pulmonary allograft recipients revealed that the mean concentration of sHLA class I was significantly higher in samples from recipients with acute rejection than in recipients with no evidence of rejection. Seventy-two percent of the patients with rejection had sHLA levels above the normal range for patients with infection or rejection. Conversely, sHLA levels were within normal limits in 94% of the control population. Time kinetic analysis revealed that in subjects with rejection, sHLA class I levels peaked in the first 2 weeks after transplantation and decreased thereafter. Increased levels of sHLA were found in patients with acute rejection but not in those with chronic rejection. Fifty-nine percent (n = 10) of the patients with infection had sHLA levels within the normal (no infection or rejection) range. The remaining 41% (n = 7) with infection had sHLA above the normal range. Fifty-seven percent (n = 4) of the latter group had cytomegalovirus infection. These results were confirmed in a prospective study carried out by analyzing paired samples obtained during and after rejection. Eight of the nine patients had high BAL sHLA class I during acute rejection, and low BAL sHLA class I levels after resolution of the acute rejection. CONCLUSION: Our data demonstrate that measurement of sHLA class I levels in BAL samples is a sensitive indicator of acute rejection.
BACKGROUND:Human leukocyte antigen (HLA) class I antigens, are glycoproteins expressed on the cell surface and are also secreted (sHLA) into the surrounding fluids. This study investigates whether pulmonary allograft rejection is associated with an increased amount of sHLA class I in the bronchoalveolar lavage (BAL) fluid. METHODS: Enzyme-linked immunosorbant assays were used to measure sHLA class I levels in BAL samples from 66 lung transplant recipients. RESULTS: Analysis of pulmonary allograft recipients revealed that the mean concentration of sHLA class I was significantly higher in samples from recipients with acute rejection than in recipients with no evidence of rejection. Seventy-two percent of the patients with rejection had sHLA levels above the normal range for patients with infection or rejection. Conversely, sHLA levels were within normal limits in 94% of the control population. Time kinetic analysis revealed that in subjects with rejection, sHLA class I levels peaked in the first 2 weeks after transplantation and decreased thereafter. Increased levels of sHLA were found in patients with acute rejection but not in those with chronic rejection. Fifty-nine percent (n = 10) of the patients with infection had sHLA levels within the normal (no infection or rejection) range. The remaining 41% (n = 7) with infection had sHLA above the normal range. Fifty-seven percent (n = 4) of the latter group had cytomegalovirus infection. These results were confirmed in a prospective study carried out by analyzing paired samples obtained during and after rejection. Eight of the nine patients had high BAL sHLA class I during acute rejection, and low BAL sHLA class I levels after resolution of the acute rejection. CONCLUSION: Our data demonstrate that measurement of sHLA class I levels in BAL samples is a sensitive indicator of acute rejection.