Urinary N-methylhistamine as an indicator of bone marrow involvement in mastocytosis.

Abstract

Thirty-seven patients with mastocytosis and unexplained elevated levels of urinary N-methylhistamine who were undergoing bone marrow biopsy were studied with respect to the diagnosis of mastocytosis and the manifestations of the disease. These patients were from a group of 66 patients from whom a bone marrow biopsy was obtained and urinary N-methylhistamine levels were measured in the period 1990-1998. In seven (19%) of the 37 patients, mastocytosis was limited to the skin. Five (14%) of the 37 patients showed accumulation of mast cells in the bone marrow without characteristic skin lesions, whereas seven (19%) of the 37 patients showed increased numbers of mast cells both in the skin and the bone marrow. Eighteen (49%) of the 37 patients with elevated N-methylhistamine did not have mast cell accumulation in either the skin or the bone marrow biopsy. The median level of N-methylhistamine in the urine of patients with mastocytosis limited to the skin was 245 micro mol/mol creatinine. The average level of N-methylhistamine was 509 micro mol/mol creatinine in patients with mast cell accumulation in the bone marrow and cutaneous mastocytosis. There was a significant difference in the levels of N-methylhistamine in patients with mast cell accumulation in the bone marrow biopsy compared with those without. The likelihood of mastocytosis with mast cell accumulation in the bone marrow biopsy at a given level of N-methylhistamine was calculated. It was established that an N-methylhistamine level of 297 micro mol/mol creatinine or higher may be considered as a threshold indicator for obtaining a bone marrow biopsy in patients suspected of mastocytosis with mast cell accumulation in the bone marrow. For practical purposes, we propose to consider the cut-off level of approximately 300 micro mol/mol N-methylhistamine creatinine for this assay.

• Authors: A P Oranje, P G H Mulder, R Heide, B Tank, P Riezebos, A W van Toorenenbergen
• Journal: Clinical and experimental dermatology (Clin Exp Dermatol) Vol. 27 Issue 6 Pg. 502-6 (Sep 2002) ISSN: 0307-6938 [Print] England
• PMID: 12372095 (Publication Type: Journal Article)

Chemical References

• Biomarkers
• Methylhistamines
• N-methylhistamine

Topics

• Biomarkers (urine)
• Biopsy
• Bone Marrow (pathology)
• Humans
• Mast Cells (pathology)
• Mastocytosis (pathology, urine)
• Methylhistamines (urine)
• ROC Curve
• Sensitivity and Specificity
• Skin (pathology)