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Hirszfeld, Ludwik (1884–1954) 326 histamine release factors (HRFs)
Ludwik Hirszfeld.
mouse α chain hinge region. Four exons encode the γ-3
chains of humans, and two exons encode human δ chains.
Hirszfeld, Ludwik (1884–1954)
Hirszfeld and Emil von Dungern studied the genetics of
blood groups.
histaminase
A common tissue enzyme, termed diamine oxidase, that
transforms histamine into imidazoleacetic acid, an inactive
substance.
histamine
A biologically active amine (i.e., δ-aminoethylimidazole)
with a molecular weight of 111 kDa that induces contraction
of the smooth muscles of human bronchioles and
small blood vessels, increased capillary permeability, and
H 3 C
Monamine
oxidase
METHYLIMIDAZOLE
ACETIC ACID
H 3 C
Histamine-N-methyltransferase
N N
N
N
HISTIDINE
HISTAMINE
CH 2
CH 2
CH 2
O
HN N
C OH
increased secretion by the mucous glands of the nose and
bronchial tree. It is a principal pharmacological mediator of
immediate (type I) hypersensitivity (anaphylaxis) in humans
and guinea pigs. Although found in many tissues, it is especially
concentrated in mast cells of the tissues and basophils
of the blood. It is stored in their cytoplasmic granules and is
released following cross linking of immunoglobulin E (IgE)
antibodies by a specific antigen on their surfaces. It is produced
by the decarboxylation of histidine through the action
of histidine decarboxylase. When histamine combines with
H 1 receptors, smooth muscle contraction and increased
vascular permeability may result. Combination with H 2
receptors induces gastric secretion and blocks mediator
release from mast cells and basophils. It may interfere with
suppressor T cell function. Histamine attracts eosinophils
that produce histaminase, which degrades histamine.
histamine release assay
In 4 to 13% of allergic patients, the immunoglobulin
E (IgE)-mediated release of histamine from basophils
depends on cytokines. These anti-IgE-non-releasers respond
to f–Met–Leu–Pro (FMLP), which bypasses the IgE receptor
pathway. Histamine release assays are valuable when
skin testing and RAST function suboptimally, especially in
patients with urticaria and atopic dermatitis in whom only
a weak correlation between IgE and disease is apparent.
Histamine release assays may be informative in patients
with urticaria, asthma, and atopic dermatitis.
histamine release factors (HRFs)
Protein cytokines that cause release of histamine from
basophils and mast cells. The 12-kDa HRF is similar to
connective-tissue-activating peptide III (CTAP-III) and
its degradation product, neutrophil-activating peptide 2
(NAP-2). The sera of patients with chronic idiopathic urticaria
(CIU) contain a histamine-releasing factor in the IgG
fraction of serum that correlates with disease activity.
HOCH2 HN N
O
HO
CH 2
HN N
NH 2
HN
PRPP
+
ATP
ADP
+
PPi + Pi
CH 2
CH
Diamine oxidase
IMIDAZOLE ACETIC ACID
CH2 C OH
O
OH
O
CH 2
COH
NH 2
Histidine decarboxylase
Pi
N
NH 2
Secretion
Imidazole acetate phosphoribosyl transferase
Phosphoribotidylimidazole acetyl phosphatase
CH 2 C O
OH
RIBOSIDE-N-3 IMIDAZOLE
ACETIC ACID
The synthesis of histamine, a principal mediator of immediate (Type I) hypersensitivity reactions.