Histamine metabolism in polycythaemia vera

Area of Science:

• Hematology
• Biochemistry

Background:

• Polycythaemia vera (PV) is a myeloproliferative neoplasm characterized by increased red blood cell mass.
• Histamine plays a role in various physiological processes, and its metabolism can be altered in certain diseases.

Purpose of the Study:

• To investigate histamine metabolism in patients with polycythaemia vera (PV) at different disease stages.
• To compare histamine metabolism in PV patients with healthy controls and patients suffering from secondary polycythaemia.

Main Methods:

• Measurement of blood and urinary histamine levels.
• Quantification of urinary histamine metabolites: methylhistamine (MeHi) and 1-methyl-4-imidazoleacetic acid (MeImAA).
• Correlation analysis between metabolite excretion, clinical parameters (blood counts, spleen volume), and histamine levels.

Main Results:

• Patients with active PV exhibited significantly higher excretion of MeHi and MeImAA compared to controls and secondary polycythaemia, suggesting increased histamine formation.
• Blood histamine levels were significantly elevated in PV patients, unlike those with secondary polycythaemia.
• Urinary histamine excretion remained within normal ranges in PV patients.
• No correlation was found between increased histamine formation and histamine-related symptoms like pruritus or duodenal ulcers.

Conclusions:

• Active polycythaemia vera is associated with an increased histamine formation and elevated blood histamine levels.
• The observed histamine metabolic disturbance in PV shares similarities with findings in chronic myeloid leukaemia.
• Increased histamine formation in PV does not appear to directly correlate with common histamine-related symptoms.