SOLUBLE HLA CLASS-I AND CLASS-II CONCENTRATIONS IN FACTOR-VIII AND PCC PREPARATIONS

Soluble HLA class 1 (sHLA-CI) and class II (sHLA-CII) molecules were quantitated in 11 commercially available factor VIII and prothrombin complex concentrate (PCC) preparations by enzyme-linked immunosorbent assays (ELISA). In 4 preparations, we detected traces of sHLA-CI (0.01-0.07 mg/l), and in 7 hemostatic preparations small amounts of sHLA-CII molecules (0.02-0.28 mg/l). The concentrations of these contaminant molecules are unequivocally below the mean values of sHLA in human plasma (sHLA-CI: 1.01+/-0.72 mg/l; sHLA-CII: 1.53+/-2.44 mg/l). Based on the total amount of chronically administered factor VIII or PCC, contaminating sHLA molecules may be in principle able to exert immunomodulatory effects in patients treated with such preparations.