Leukotrienes in patients with clinically active multiple sclerosis.

OBJECTIVES: The role of leukotrienes (LTs) in the pathophysiology of multiple sclerosis (MS) has been controversially discussed in the past. Studies of LTs in the cerebrospinal fluid (CSF) revealed different results mainly because of analytical difficulties. MATERIAL AND METHODS: In the present study we used highly sensitive and specific analytical methods for measuring LTs in the CSF as well as in urine samples from 20 patients with active MS and 20 control patients with noninflammatory neurological disorders. RESULTS: LTB4 concentrations in CSF were almost twice as high in MS patients compared with controls (P < 0.001). CSF concentrations of the cysteinyl-LTs (LTC4, LTD4 and LTE4) as well as urinary LTE4 showed no significant differences compared with controls (P > 0.05). In addition, there was no significant association between CSF pleocytosis, clinical severity or time of disease onset. CONCLUSIONS: The increased concentration of LTB4 in the CSF of MS patients may indicate a biological importance for this mediator in MS.

Analysis of leukotrienes in cerebrospinal fluid of a reference population and patients with inborn errors of metabolism: further evidence for a pathognomonic profile in LTC(4)-synthesis deficiency.

Cysteinyl leukotrienes (LTC(4), LTD(4), LTE(4)) are potent lipid mediators derived from arachidonate in the 5-lipoxygenase pathway. Recently, the first inborn error of leukotriene synthesis, LTC(4)-synthesis deficiency, has been identified in association with a fatal developmental syndrome. The absence of leukotrienes in cerebrospinal fluid was one of the most striking biochemical findings in this disorder. We analysed leukotrienes in cerebrospinal fluid of patients with a broad spectrum of other well-defined inborn errors of metabolism, including glutathione synthetase deficiency (n=2), Zellweger syndrome (n=3), mitochondrial disorders (n=8), fatty acid oxidation defects (n=7), organic acidurias (n=7), neurotransmitter defects (n=5) and patients with non-specific neurological symptoms, as a reference population (n=120). The concentrations of leukotrienes were not related to age. Representative percentiles were calculated as reference intervals of each leukotriene. In all patients with an inborn error of metabolism concentration of cysteinyl leukotrienes and LTB(4) did not differ from the reference group. Our results indicate that absence of cysteinyl leukotrienes (<5 pg/ml) in association with normal or increased LTB(4) (50.0-67.3 pg/ml) is pathognomonic for LTC(4)-synthesis deficiency. The unique profile of leukotrienes in cerebrospinal fluid in this new disorder is primarily related to the defect and represents a new diagnostic approach.

A severely affected infant with absence of cysteinyl leukotrienes in cerebrospinal fluid: further evidence that leukotriene C4-synthesis deficiency is a new neurometabolic disorder.

Leukotrienes are potent oxygenated metabolites derived from the 5-lipoxygenase pathway of arachidonic acid metabolism. They comprise the cysteinyl leukotrienes (LTC4, LTD4, LTE4) and LTB4. The rate limiting step in the formation of cysteinyl leukotrienes is the conversion of LTA4 to LTC4 catalyzed by the enzyme LTC4 synthase. Recently, the first inborn error of leukotriene synthesis, LTC4-synthesis deficiency, has been identified in a patient with a fatal developmental syndrome. We report on an additional infant presenting with severe muscular hypotonia, symmetrical extension in the lower extremities and psychomotor retardation who died at the age of 6 months. Despite intensive investigations no specific diagnosis could be made. Leukotrienes were subsequently analyzed in the cerebrospinal fluid. Concentrations of LTC4, LTD4 and LTE4 were below the detection limit (< 5 pg/ml) whereas LTB4 was found to be in the upper normal range. The absence of cysteinyl leukotrienes with normal LTB4 concentration in cerebrospinal fluid is unique and seems to be pathognomonic for LTC4-synthesis deficiency. Our patient most likely represents the second case described so far with this condition. This report provides further evidence that LTC4-synthesis deficiency represents a new neurometabolic disorder.

LTB4 and LTC4 are absent in the cerebrospinal fluid of human immunodeficiency virus type 1-seropositive persons with toxoplasmic encephalitis: evidence for inhibition of 5-lipoxygenase by Toxoplasma gondii.

Previous studies on macrophages have shown that Toxoplasma gondii alters the metabolism of arachidonic acid with subsequent inability to generate leukotrienes (LT)s. LTB4 and LTC4 were analyzed in cerebrospinal fluid of 3 groups of human immunodeficiency virus (HIV) type 1-seropositive patients: with toxoplasmic encephalitis (TE) (n=10), with herpes simplex encephalitis (n=5), and without encephalitis (n=10) and in HIV-1-seronegative controls without inflammatory diseases (n=30) by specific immunoassays and gas chromatography-mass spectrometry. In HIV-1-seropositive subjects with TE, LTB4 and LTC4 were below the detection limit (<5.0 pg/mL) and thus significantly decreased (P<.01) compared with HIV-1-seropositive patients with herpes simplex encephalitis (LTB4, 148.5+/-47.6 pg/mL; LTC4, 116.4+/-36.9 pg/mL) and in those without encephalitis (LTB4, 46.1+/-16.8 pg/mL; LTC4, 48.3+/-21.3 pg/mL), and in controls (LTB4, 43.6+/-21.2; LTC4, 45.2+/-18.9 pg/mL). These results point to an essential role of inhibition of 5-lipoxygenase with subsequent failure of LT release as an important mechanism for the survival of T. gondii in vivo.