Diagnosis of Allergy to Mammals and Fish: Cross-Reactive vs. Specific Markers.

PURPOSE OF REVIEW: Allergen extracts are still widely used in allergy diagnosis as they are regarded as sensitive screening tools despite the fact that they may lack some minor allergens. Another drawback of extracts is their low specificity, which is due to the presence of cross-reactive allergens. Progress in allergen identification has disclosed a number of allergenic molecules of homologous sequence and structure which are present in different animal species. This review summarizes recent advances in mammalian and fish allergen identification and focuses on their clinical relevance. RECENT FINDINGS: Serum albumins and parvalbumins are well-known animal panallergens. More recently several members of the lipocalin family were found to be cross-reactive between furry animals whereas in fish, additional allergens, enolase, aldolase and collagen, were found to be important and cross-reactive allergens. New epidemiological studies have analysed the prevalence and clinical relevance of mammalian and fish components. Primary sensitization can be distinguished from cross-sensitization by using marker allergens. Although substantial progress has been made in allergen identification, only few markers are commercially available for routine clinical practice.

Biomarker evaluation of skeletal muscle toxicity following clofibrate administration in rats.

The use of sensitive biomarkers to monitor skeletal muscle toxicity in preclinical toxicity studies is important for the risk assessment in humans during the development of a novel compound. Skeletal muscle toxicity in Sprague Dawley Rats was induced with clofibrate at different dose levels for 7 days to compare standard clinical pathology assays with novel skeletal muscle and cardiac muscle biomarkers, gene expression and histopathological changes. The standard clinical pathology assays aspartate aminotransferase (AST), alanine aminotransferase (ALT), and creatine kinase (CK) enzyme activity were compared to novel biomarkers fatty acid binding protein 3 (Fabp3), myosin light chain 3 (Myl3), muscular isoform of CK immunoreactivity (three isoforms CKBB, CKMM, CKMB), parvalbumin (Prv), skeletal troponin I (sTnI), cardiac troponin T (cTnT), cardiac troponin I (cTnI), CKMM, and myoglobin (Myo). The biomarker elevations were correlated to histopathological findings detected in several muscles and gene expression changes. Clofibrate predominantly induced skeletal muscle toxicity of type I fibers of low magnitude. Useful biomarkers for skeletal muscle toxicity were AST, Fabp3, Myl3, (CKMB) and sTnI. Measurements of CK enzyme activity by a standard clinical assay were not useful for monitoring clofibrate-induced skeletal muscle toxicity in the rat at the doses used in this study.

Early-life lead exposure recapitulates the selective loss of parvalbumin-positive GABAergic interneurons and subcortical dopamine system hyperactivity present in schizophrenia.

Environmental factors have been associated with psychiatric disorders and recent epidemiological studies suggest an association between prenatal lead (Pb(2+)) exposure and schizophrenia (SZ). Pb(2+) is a potent antagonist of the N-methyl-D-aspartate receptor (NMDAR) and converging evidence indicates that NMDAR hypofunction has a key role in the pathophysiology of SZ. The glutamatergic hypothesis of SZ posits that NMDAR hypofunction results in the loss of parvalbumin (PV)-positive GABAergic interneurons (PVGI) in the brain. Loss of PVGI inhibitory control to pyramidal cells alters the excitatory drive to midbrain dopamine neurons increasing subcortical dopaminergic activity. We hypothesized that if Pb(2+) exposure in early life is an environmental risk factor for SZ, it should recapitulate the loss of PVGI and reproduce subcortical dopaminergic hyperactivity. We report that on postnatal day 50 (PN50), adolescence rats chronically exposed to Pb(2+) from gestation through adolescence exhibit loss of PVGI in SZ-relevant brain regions. PV and glutamic acid decarboxylase 67 kDa (GAD67) protein were significantly decreased in Pb(2+) exposed rats with no apparent change in calretinin or calbindin protein levels suggesting a selective effect on the PV phenotype of GABAergic interneurons. We also show that Pb(2+) animals exhibit a heightened locomotor response to cocaine and express significantly higher levels of dopamine metabolites and D2-dopamine receptors relative to controls indicative of subcortical dopaminergic hyperactivity. Our results show that developmental Pb(2+) exposure reproduces specific neuropathology and functional dopamine system changes present in SZ. We propose that exposure to environmental toxins that produce NMDAR hypofunction during critical periods of brain development may contribute significantly to the etiology of mental disorders.

Vitamin B12 as a potential compliance marker for fish intake.

OBJECTIVES: The aim of the present study was to investigate whether the following four markers: vitamin B12, selenium, vitamin D, and parvalbumin may be used as compliance markers for fish intake. METHODS: Blood samples from a randomized cross-over herring intervention study (n = 32) were analysed by HPLC and immunochemistry. The criteria were that plasma or serum concentrations of candidate compliance markers after the herring diet should increase significantly compared to starting concentrations. In addition, the reference meat diet should not yield an increase in plasma concentration of the candidate marker. RESULTS: Vitamin B12 and selenium met the set criteria for indicating a correlation between the marker and fish intake with significant increases in serum concentrations at 8.9% (p = 0.008) and 4.6% (p = 0.02), respectively, after a 6-week herring intervention (5 meals a week). Parvalbumin and 25-hydroxy vitamin D3 levels did not increase significantly after the herring interventions. CONCLUSIONS: Vitamin B12 may be suitable as a compliance marker for fish intake. Although selenium also met the criteria, the change in selenium serum concentrations was small compared to the change in vitamin B12 levels.

Parvalbumin--the major tropical fish allergen.

Fish allergy is common in countries where consumption is high. Asian nations are amongst the world's largest consumers of fish but the allergen profiles of tropical fish are unknown. This study sought to evaluate the allergenicity of four commonly consumed tropical fish, the threadfin (Polynemus indicus), Indian anchovy (Stolephorus indicus), pomfret (Pampus chinensis) and tengirri (Scomberomorus guttatus). Immunoglobulin E (IgE) cross-reactivity with parvalbumin of cod fish (Gad c 1), the major fish allergen, was also studied. Detection of tropical fish and cod specific-IgE was performed by UniCap assay, and skin prick tests were also carried out. The IgE-binding components of tropical fish were identified using IgE immunoblot techniques, and cross-reactivity with Gad c 1 was assessed by ELISA inhibition and IgE immunoblot inhibition. Clinically, nine of 10 patients studied were allergic to multiple fish. All patients exhibited detectable specific-IgE to cod fish (10 of 10 skin prick test positive, eight of 10 UniCap assay positive) despite lack of previous exposure. The major allergen of the four tropical fish was the 12-kDa parvalbumin. IgE cross-reactivity of these allergens to Gad c 1 was observed to be moderate to high in the tropical fish studied. Parvalbumins are the major allergens in commonly consumed tropical fish. They are cross-reactive with each other as well as with Gad c 1. Commercial tests for cod fish appear to be sufficient for the detection of tropical fish specific-IgE.

Renal expression of parvalbumin is critical for NaCl handling and response to diuretics.

The distal convoluted tubule (DCT) plays an essential role in the reabsorption of NaCl by the kidney, a process that can be inhibited by thiazide diuretics. Parvalbumin (PV), a Ca(2+)-binding protein that plays a role in muscle fibers and neurons, is selectively expressed in the DCT, where its role remains unknown. We therefore investigated the renal phenotype of PV knockout mice (Pvalb(-/-)) vs. wild-type (Pvalb(+/+)) littermates. PV colocalized with the thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC) in the early DCT. The Pvalb(-/-) mice showed increased diuresis and kaliuresis at baseline with higher aldosterone levels and lower lithium clearance. Acute furosemide administration increased diuresis and natriuresis/kaliuresis, but, surprisingly, did not increase calciuria in Pvalb(-/-) mice. NaCl supplementation of Pvalb(-/-) mice increased calciuria at baseline and after furosemide. The Pvalb(-/-) mice showed no significant diuretic response to hydrochlorothiazide, but an accentuated hypocalciuria. A decreased expression of NCC was detected in the early DCT of Pvalb(-/-) kidneys in the absence of ultrastructural and apoptotic changes. The PV-deficient mice had a positive Ca(2+) balance and increased bone mineral density. Studies in mouse DCT cells showed that endogenous NCC expression is Ca(2+)-dependent and can be modulated by the levels of PV expression. These results suggest that PV regulates the expression of NCC by modulating intracellular Ca(2+) signaling in response to ATP in DCT cells. They also provide insights into the Ca(2+)-sparing action of thiazides and the pathophysiology of distal tubulopathies.

Immunochemical analysis of some proteins in cerebrospinal fluid and serum of patients with ischemic strokes.

Immunochemical studies of gamma gamma-neuron specific enolase (NSE), parvalbumin (PV), S-100 protein (S-100) and acidic fibrillary glial protein (GFAP) were studied in the cerebrospinal fluid and blood serum in 7 patients with ischemic cerebral stroke, aged 57 to 81 years. Cerebrospinal fluid and the first blood sample were taken on the first or second day of the disease. Further blood samples were taken once a week till the end of patients hospitalization, ending by patients discharge or death. Immunochemical identification of proteins under study were performed with Western-blotting technique. It was found that all proteins studied were present in both cerebrospinal fluid and blood serum on the first two days of the disease in small quantities. The blood content of both NSE and PV increased significantly during the first week of the disease. Both proteins disappeared from the blood serum between the second and fourth disease weeks. S-100 protein and GFAP contents in the blood reached significantly high level within the time interval between second and fifth disease weeks, and remained at a relatively high level till patients' death. In all cases computed tomography study and/or brain autopsy revealed extensive ischemic foci localized within areas supplied by the middle cerebral artery. No clear-cut correlation between extensiveness of the ischemic cerebral damage and the content of the proteins studied in both cerebrospinal fluid and blood serum was found. However, our data indicate that serial studies of the above proteins in patients with ischemic stroke may be useful in monitoring the progress of the disease, and occasionally in the prognosis at least in some cases.

Serum parvalbumin, an indicator of muscle disease in murine dystrophy and myotonia.

The soluble Ca(++)-binding protein parvalbumin (PV) is highly concentrated in fast muscle fibers of the wild type mouse. Employing Sandwich ELISA, we have shown that PV is present in the serum of normal mice and that its level is indicative of the disease status of muscle. Elevated PV levels were found in mice with X-linked dystrophy (mdx) and reduced levels in myotonic (ADR) mice. Serum creatine kinase (CK) levels were elevated in mdx and normal in ADR mice. Because myotonic mouse muscle has a strongly reduced PV content, the reduced PV serum level in ADR mice indicated that serum PV is derived from skeletal muscle. Serum PV in mdx mice, in which muscle PV content is close to normal, is a measure of the necrosis of fast muscle fibers. Serum levels of PV and CK were not significantly elevated in heterozygous (mdx/+) carrier females. Serum PV in Duchenne patients was below the limit of detection.