Peripheral blood lymphocytes immunophenotype and serum concentration of soluble HLA class I in burn patients

The level of the soluble form of histocompatibility class I antigens, associated with β2-microglobulin (sHLA-I) has been determined by an ELISA sandwich method in serum from burned patients (n=42) and healthy volunteers (n=30). The sHLA-I level was insignificantly increased in burn patients at the stage of burn shock (1284±324 U/ml, mean±S.E.M.) and after day 28 postburn (1368±258 U/ml) compared to volunteers (1150±90 U/ml). At the same time a decrease of sHLA-I levels between 4 and 14 days (638±178 U/ml) was determined (P<0.05). Increased levels of sHLA, though not significant, were detected in patients with TBSAB >70% in comparison to patients with TBSAB from 30 to 70% during burn shock (1493±528 and 1075±339 U/ml, respectively). Expression of membranous HLA class I antigens (mHLA-I) in peripheral blood lymphocytes (PBLs) was assayed simultaneously by indirect immunofluorescence. The number of CD3+, CD4+, CD8+, CD25+, CD71+ and CD26+ lymphocytes was also evaluated. The expression of mHLA-I in PBLs was increased significantly in patients with TBSAB <70% at early postburn period. Daily monitoring showed that the relative numbers of CD25+ and CD71+ lymphocytes in patients varied greatly within short intervals of time during burn shock. The data obtained suggest that mHLA-I expression can reflect postburn lymphocyte activation. The serum content of sHLA-I does not depend on lymphocyte number or activated lymphocyte number in peripheral blood at burned patients.