Lymphocyte-specific protein 1: a specific marker of human leucocytes

Immunology. 1999 Feb;96(2):262-71. doi: 10.1046/j.1365-2567.1999.00677.x.


While both murine and human homologues of the LSP1 gene (lymphocyte-specific gene 1) and its protein products have been identified, studies on human LSP1 have been limited. The present report describes a detailed immunocytochemical study of the distribution and localization of human LSP1 in both normal and neoplastic cells and tissues. The specificity of the monoclonal anti-LSP1 reagent was confirmed by expression cloning and transfection studies. The intracellular 60 000 MW LSP1 protein was found to be present in peripheral blood B cells, monocytes and granulocytes but absent in a subpopulation of circulating T cells (10-15% of CD3-positive T cells). The presence of LSP1 protein in medullary thymocytes, but only in scattered cortical thymocytes, provided additional evidence for heterogeneity of expression in T cells. Novel observations also included the presence of LSP1 in plasma cells, dendritic cells and Langerhans' cells. The leucocyte-restricted distribution of LSP1 protein means that it may play an important role in haematopathology. LSP1 protein was detected in a wide range of leukaemias and lymphomas, particularly of B-cell origin, and in tumour cells in classical Hodgkin's disease. Of interest was the indication of a reciprocal relationship in the expression of LSP1 and ALK (anaplastic lymphoma kinase) proteins in patients with anaplastic large cell lymphoma. As the anti-LSP1 reagent used in the present study recognizes a formalin-resistant epitope it should be of considerable value in the diagnosis of routinely fixed material.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaplastic Lymphoma Kinase
  • B-Lymphocytes / chemistry
  • Biomarkers / analysis
  • Blotting, Western
  • Cell Line
  • Dendritic Cells / chemistry
  • Granulocytes / chemistry
  • Hodgkin Disease / metabolism
  • Humans
  • Immunohistochemistry
  • Langerhans Cells / chemistry
  • Leukemia / metabolism*
  • Leukocytes / chemistry*
  • Lymphoma / chemistry*
  • Lymphoma, Large B-Cell, Diffuse / chemistry
  • Monocytes / chemistry
  • Phosphoproteins / analysis*
  • Plasma Cells / chemistry
  • Protein-Tyrosine Kinases / analysis
  • Receptor Protein-Tyrosine Kinases
  • Thymus Gland / chemistry


  • Biomarkers
  • Phosphoproteins
  • lymphocyte-specific protein p50
  • ALK protein, human
  • Anaplastic Lymphoma Kinase
  • Protein-Tyrosine Kinases
  • Receptor Protein-Tyrosine Kinases