HELPER T-LYMPHOCYTE PRECURSOR FREQUENCY-ANALYSIS IN ALLOREACTIVITY DETECTION

The utility of IL-2 secreting helper T lymphocyte precursors (HTLp) fr equency testing has been evaluated for detecting alloreactivity. The f requency of HTLp was approached by limiting dilution assay. High HTLp frequency was detected in 20 out of 30 HLA matched unrelated pairs (67 %). The comparison of HTLp and CTLp (cytotoxic T lymphocyte precursors ) frequencies in. HLA matched unrelated pairs showed that the two exam inations are not fully alternative in detecting alloreactivity. This c ould suggest the utility of combined testing of both HTLp and CTLp fre quencies for alloreactivity assessment. In contrast, five positive HTL p values were only found among 28 HLA genotypic identical siblings (18 %). Previous CTLp limiting dilution studies showed very low or undetec table CTLp frequency results in that group. For that, HTLp assay remai ns to be the only cellular in vitro technique detecting alloreactivity in these combinations.