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There exists diseases in rheumatology fulfilling classification criteria for either rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). They are called "rhupus". We retrospectively analyzed the data base "GLIMS" of the CHU de Liège from the starting date of november 2005 until april 2011 to identified those patients that were positive for the anti-sDNA antibody marker of SLE and for the anti-CCP antibody, marker of RA. Fourteen patients were identified and two other patients were added, one suffering from SLE, and the other from RA, and likely to be rhupus. Of the 16 patients analyzed, 9 were real RA with anti-dsDNA antibodies induced by anti-TNF-alpha therapies. Seven were candidates to be rhupus and 6 were retained. They were all women, with a median age of 51 years and in addition were all anti-SS-A antibody positive.

Natriuretic peptides, particularly BNP and NT-proBNP, are increasingly used as screening test in patients with symptoms suggestive of heart failure (HF). Due to their high negative predictive values, natriuretic peptide determinations allow to exclude chronic HF with great certainty and to identify patients for whom echography is not necessary. These biomarkers are also useful for diagnostic purposes, high plasma levels being related to an increased risk of cardiovascular hospitalisation and death. Risk stratification in patients with HF symptoms is based on "low" and "high" cut-off limits, for which different values have been proposed. The aim of this paper is to discuss the delineation of the decision limits and the intermediate grey zone in comparison to NT-proBNP reference values obtained in a representative group of subjects living in the Liège area (Belgium). Data were analysed in relation to age and gender, two of the main parameters influencing the natriuretic peptide plasma levels.

The consequences of Hymenoptera venom anaphylaxis are very severe but it is not obvious to predict which reactions will occur in one single patient when he is stung for the second time. For a couple of years, many new laboratory tests have been experimented and many studies published. CAST, BAT, WB, tryptase, sIgE and sIgG4 are the new valuable additional diagnostic tools that can help the decision to perform an immunotherapy or to discontinue this therapy after 3 years. The aim of our study was to determine which could be the profile of a desensitized patient and to screen for good candidates for venom immunotherapy.

Immunoassays, or assays with antibodies as reagents, are widely used in medical laboratories. These assays are used to identify and quantify various substances in biological fluids, such as specific proteins (various tissue markers, markers of inflammation, hormones, coagulation factors...) or immunoglobulins (viral or bacterial antibodies, auto-antibodies...) and even both viral antigens and antibodies (HIV virology). The use of monoclonal antibodies allowed, through their specificity for a single epitope of the target molecule, the development of increasingly sophisticated immunoassays. In particular, the use of monoclonal antibodies with microarrays permits the simultaneous determination of various proteins (inflammatory profile, cardiac profile, specifics IgE...) quickly and accurately. Very important tools in the clinical laboratory, immunoassays techniques are, however, subject to various analytical interferences which may be responsible for significant changes in the test results.

In contrast to a polyclonal antiserum, a monoclonal antibody is specific to a single epitope on the surface of a complex antigen. In 1975, Kohler and Milstein produced the first monoclonal antibodies by using a method which rapidly became a key technology in immunology. By fusing activated antibody-forming cells (B cells) with myeloma cells, they obtained hybrid cells--the so-called hydridomas--which combine the ability of the activated B cells to secrete a single species of antibody and the immortality of the myeloma cell. The selected hybridomas proliferate continuously, their clonal progeny providing an unending supply of antibody with a single specificity. These antibodies have found many applications in basic research and in vitro diagnosis. In the clinical laboratory, monoclonal antibodies are used as reagents in immunoassays, often replacing traditional antisera. Many years of development and innovation were needed to humanize monoclonal antibodies in order to make them usable in human therapy.

We have evaluated the prevalence of the 25-hydroxy vitamin D (25VTD) deficiency in recently pregnant women and new mothers in the area of Liege, Belgium. The study took place in November 2006. Twenty four women who underwent a positive pregnancy test and 65 new mothers were enrolled. The level of 25VTD did not differ between the two groups. Only 12% of the pregnant women and 14% of the new mothers (>12 ng/ml) had an optimal level of 25VTD (>30 ng/ ml). We also observed a severe 25VTD deficiency in 21% of pregnant women and 32% of new mothers. Our results showed that more than 80% of pregnant women and new mothers in the area of Liege presented a deficiency in 25VTD. In Belgium, daily vitamin supplementation of pregnant women is common, but the level of vitamin D3 concentration range from 10 microg (400 UI) to zero microg. In our area, vitamin D production in the skin is not always important enough to achieve optimal levels. Our data show that vitamin D supplementation of pregnant women is not enough and that 25VTD deficiency is not diagnosed in this high-risk population. Children born from deficient mothers will present a higher risk of suffering from bone mineral diseases as well as other pathologies, as type 1 diabetes or neurological disorders. Of course, this insufficiency will also have an impact on mother's bone reserve, but these mothers will also be at higher risk for preeclampsia.

Auto-immune diseases represent the 3rd cause of morbidity after cardiovascular and oncologic diseases. They often occur in young subjects. Their presence is not synonymous of disease and must be associated to clinical signs to be pathological. However, their discovery can require a complement of investigations and the possibility of a follow-up because some auto-antibodies are predictive of disease. This paper is concerned with the main autoantibodies that can be picked out at the laboratory of immunology. Some technical explanations and INAMI rules are explained too.

Oxidative stress is defined as an imbalance between the production of reactive oxygen species (ROS) and the antioxidant network, in favour of the former. Our lifestyle (smoking, alcoholism, obesity, intense physical exercise), but also our inadequate diet, contributes to significantly increase the production of ROS in our organism. This is potentially associated with an increased risk of developing ageing-related pathologies such as cardiovascular diseases and cancer. As a matter of prevention, it is necessary to have in hands a high technology allowing to correctly evidence the oxidative stress status of an individual in order to render optimal our antioxidant defences and to decrease the oxidative damages in DNA, proteins and lipids.

Glomerular filtration rate (GFR) is the most frequently used parameter to evaluate the renal function. GFR may be estimated with serum creatinine, creatinine clearance based on 24 hours urine collection or Cockcroft formula. All these methods have bias. Other approaches have thus been proposed. The limitations and advantages of isotopic methods and recent mathematical approaches (MDRD formula) are reviewed.

Like other medical investigations, laboratory tests are not free from uncertainties or errors which limit their clinical value. Usually two levels of variations are identified: the analytical and biological levels. This paper presents some sources of variations and provides different examples. The concept of reference value is also discussed, as well as the clinician's viewpoint regarding the interpretation of laboratory results.

Homocystinuria is an uncommon genetic disease characterized by a marked increase of serum homocysteine (HCY), an intermediate of methionine metabolism. In patients with homocystinuria, hyperhomocysteinemia promotes the development of atherosclerotic lesions and is responsible for premature coronary artery disease. Recently, several studies have also demonstrated that moderate hyperhomocysteinemia--not necessarily linked to an inborn metabolic defect--may also be considered as an independant risk factor for cardiovascular disease. The main mechanisms of HCY atherogenic action are thought to be LDL oxydation, inhibition of vascular endothelium growth combined with stimulation of smooth muscular cells proliferation, and interference with the coagulation and fibrinolytic systems. Cofactors of key enzymes in HCY metabolism, folic acid, vitamin B12 and vitamin B6, may be given, alone or in combination, for the treatment of hyperhomocysteinemia. Homocysteinemia can be assessed by basal plasma HCY concentration and/or by HCY levels measured after a methionine loading test. Mainly measured till now in specialized laboratories using rather complex techniques (HPLC, GCMS, amino acid analyser ...), HCY determination is today spreading widely owing to the development of automated immunoassays.

The troponin (Tn) complex consists of three protein subunits referred to as TnT, TnI and TnC. Myocardium contains TnI and TnT isoforms which are not present in skeletal muscles and which can be separated from the muscular isoforms by immunological techniques. Using commercially available immunoassays, clinical laboratories are able to determine cardiac TnT and TnI (cTnT and cTnI) as quickly and reliably as classical cardiac markers. After acute myocardial infarction, cTnT and cTnI concentrations start to increase in serum in a rather similar way than CK-MB, but return to normal after longer periods of time (approximately one week). Because of their excellent cardiac specificity, Tn subunits appear ideally suited for the differential diagnosis of myocardial and muscular damage, for example in non cardiac surgery patients, in patients with muscular trauma or with chronic muscular diseases, or after intensive physical exercise. cTnT and cTnI may also be used for detecting evidence of minor myocardial damage, and therefore may find new applications in the management of patients with unstable angina.