Lack of T-cell receptor gene rearrangements in cells involved in Langerhans cell histiocytosis.

Abstract

Studies using X-chromosome inactivation assays have recently provided evidence in support of a clonal origin of cells affected by Langerhans cell histiocytosis (LCH). A search for more specific clonal markers has led to the investigation for T-cell receptor (TCR) gene rearrangements in cells affected by LCH. Conventional southern blot analysis was used to investigate the possibility of clonal TCR gene rearrangements in tissues affected by LCH wherever possible, otherwise, a polymerase chain reaction (PCR)-based technique was employed for amplification of rearranged joint (J) and variable (V) segments of the TCR-gamma gene including the N-region. 32P-labeled PCR products were then resolved using nondenaturing polyacrylamide gel electrophoresis. The results using the PCR-based technique showed a lack of clonal rearrangement of the TCR-gamma gene in affected tissues of eight patients with different stages of LCH. Southern blot analyses performed on two of these samples confirmed germline configurations at both the TCR-C-beta and delta-2 gene loci. There is no evidence of clonal TCR gene rearrangement in cells involved by LCH. The search for a more specific clonal marker to address whether "'LCH cells" represent a neoplastic clonal transformation of cells with differentiation toward Langerhans cell phenotype continues.