Histidine Decarboxylase in Peripheral Lymphocytes of Healthy Individuals and Chronic Lymphoid Leukemia Patients

Márta BENCSÁTH1, Katalin PÁLÓCZI2, Csaba SZALAI3, Andrea SZENTHE1, Júlia SZEBERÉNYI1, András FALUS1

1Department of Genetics, Cell- and Immunobiology, Semmelweis University of Medicine, Budapest, Hungary
2National Institute of Hematology and Immunology, Budapest, Hungary
3Pal Heim Children's Hospital, Budapest, Hungary


Histidine decarboxylase (HDC), the only enzyme capable of synthetizing histamine, has been found in many proliferating cells and tissues suggesting a role of histamine in cellular proliferation. In this study expression of HDC and the significance of histamine in the proliferation of peripheral lymphocytes of five healthy persons and six patients with chronic lymphoid leukemia (CLL) was examined. Expression of HDC mRNA and the protein was proved by reverse transcriptase polymerase chain reaction and by immunoblot, respectively. The role of histamine was studied in proliferation assays by the action of irreversible HDC inhibitor (alpha-fluoromethylhistidine--aFMH) and also by competing for the intracellular binding sites of histamine using N,N-diethyl-2,4-phenylmethyl-phenoxy-ethanamine-HCl (DPPE). Inhibiting the HDC enzyme activity by aFMH and blocking the intracellular action of histamine by DPPE, a significant decrease in cell proliferation was observed in mitogen stimulated lymphocytes of healthy donors. In CLL patients the proliferation of leukemic lymphocytes was inhibited significantly by DPPE. aFMH inhibited only the de novo histamine formation but did not the proliferation. The observations suggest that HDC has functional relevance in lymphocytes, since mitogen induced lymphocyte proliferation of healthy donors is mainly enhanced by de novo synthesis and subsequent action of intracellular histamine. Alternatively, in constitutively proliferating chronic lymphoid leukemia cells we suggest that the preformed pool but not the de novo synthesized intracellular histamine interferes with cellular proliferation. Pathology & Oncology Research, Vol 4, Nr 2, 121-124, 1998

Key words: histamine; lymphocyte; cell proliferation; leukemia

Received: Jan 7, 1998; accepted: Apr 12, 1998
Correspondence: András FALUS, Department of Genetics, Cell- and Immunobiology, Semmelweis University of Medicine, Nagyvárad tér 4. Budapest H-1089, Hungary; Tel: (36)(1)2102929, Fax: (36)(1)3036968; E-mail:

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