Assessment of renal function using cystatin C and creatinine in Saudi patients after transplantation.

Background: Rapid and accurate assessment of kidney function in patients after transplantation is of utmost importance. The aim of this study was to compare the relationships of serum creatinine and serum cystatin C with an estimated glomerular filtration rate (eGFR) in kidney transplants Saudi patients after a certain period of transplantation. Materials and Methods: In this prospective study, 127 patients were categorized into three groups based on their length of survival after kidney transplantation; <1 year, from 1 to 5 years, and above 5 years after transplantation. Results of cystatin C and creatinine levels were compared by eGFR derived from estimation equation chronic kidney disease epidemiology collaboration. Results: In the three assessed periods, the mean (standard deviation) cystatin C level was 1.72 (0.57), 1.59 (0.64), and 1.82 (0.82), respectively, being highest after 5 years of transplantation, normal in 9.40%, and elevated in 90.60% of the participants, while creatinine level, decreased from 1.57 (0.53) to 1.52 (0.64) in 1-5 years, then it became the highest at 1.75 (0.69) in more than 5 years. The mean was normal in 21.30% and elevated in 78.70% of the patients. Both serum creatinine and cystatin C levels were negatively correlated with posttransplantation time in kidney transplant patients. Conclusion: The cystatin C level was statistically significantly higher after 5 years of transplantation. It is a better parameter to rule out renal dysfunction after transplantation.

Résumé Une évaluation rapide et précise de la fonction rénale chez les patients après une transplantation est de la plus importance. Le but de cette étude était de comparer les relations de la créatinine et de la cystatine C sérique avec un taux de filtration glomérulaire estimé (DFG) chez des patients saoudiens transplantés rénaux après une certaine période de transplantation. Matériel et méthodes: Dans cette étude prospective, 127 patients ont été classés en trois groupes en fonction de leur durée de survie après une transplantation rénale; <1 an, de 1 à 5 ans et plus de 5 ans après la transplantation. Les résultats des taux de cystatine C et de créatinine ont été comparés par le DFG dérivé de l'équation d'estimation de la collaboration épidémiologique sur les maladies rénales chroniques. Résultats: Au cours des trois périodes évaluées, le taux moyen (écart-type) de cystatine C était de 1,72 (0,57), 1,59 (0,64) et 1,82 (0,82), respectivement, étant le plus élevé après 5 ans de transplantation, normal dans 9,40% et élevé chez 90,60% des participants, tandis que le niveau de créatinine est passé de 1,57 (0,53) à 1,52 (0,64) en 1 à 5 ans, puis il est devenu le plus élevé à 1,75 (0,69) en plus de 5 ans. La moyenne était normale chez 21,30% et élevée chez 78,70% des patients. Les taux sériques de créatinine et de cystatine C étaient corrélés négativement avec le temps post-transplantation chez les patients transplantés rénaux. Discussion: Le taux de cystatine C était significativement plus élevé après 5 ans de transplantation. C'est un meilleur paramètre pour exclure un dysfonctionnement rénal après une transplantation.

Microbicidal activity measured by flow cytometry: Optimization and standardization for detection of primary and functional deficiencies.

Microbicidal activity is related to the production of reactive oxygen species (ROS) that can be measured by flow-cytometry using rhodamine 123 (R123). Few assays have been proposed to measure ROS production, usually on heparinized samples but none of them is standardized. Here we propose to improve the test by selecting polymorphonuclears (PMN) and monocytes, labelled and activated in one step to keep the test short, and to standardize the process even between different systems (i.e. Navios™ and FACSCanto™) using fluorescence intensity target setting ("FITS"). We applied this test on 15 patients without inflammation, 19 patients from an intensive care unit (ICU) and 11 healthy volunteers. RESULTS: Provided calcium restitution, we show that the test can be performed on EDTA that is a better sample preservative. The results were highly correlated between instruments (r2=0.898). PMN CD16 (and not CD14) expression was altered under stimulation with E. coli (MdFI=239.3±93.5) or PMA (139.7±76.8) as compared to resting sample (307.6±145.1). RH123 was strongly and homogeneously induced by PMA (14.2±6.6) and more heterogeneously by E. coli (MdFI 21.9±23.4) as compared to unstimulated PNN (0.9±1.3, p<0.0001). The test is useful not only for genetic disorders but also for secondary deficiencies as observed in ICU (E. coli RH123 MFI=10.5±11.1 patients vs 30.1±26.5 in healthy donors). In ICU, CD16 expression was already altered on unstimulated samples (MdFI=197.4±131.2 vs 418, 2±81.3 in healthy donors; p≤0.0001). Bacterial stimulation was dependent of the complement that partly explains deficiency to bacterial stimulus in ICU patients.

New tools in cytometry.

Cytometry aims to analyze cells, of any type, using dedicated instruments. The quantitative aspect makes flow cytometry (FCM) a good complementary tool for morphology. Most of the identification tools are based on immunostaining of cell structure details and more and more tools are available in terms of specificities and labels. FCM is under exponential development thanks to technical, immunological and data analysis progresses. Actual generations are now routinely using 6 to 10 simultaneous immuno-labeling on 20 to 100,000 cells, at high speed and short sample preparation and can easily detect rare events at frequency below 10-4 cells. Data interpretation is complex and requires expertise. Mathematical tools are available to support analysis and classification of cells based. Cells from tissues can also be analyzed by FCM after mechanical and or enzymatic separation, but in situ cells can also be analyzed with the help of cytometry. Very new instruments bring spectral analysis, image in flow and mass spectrometry. Medical applications are very broad, notably in hemopathies, immunology, solid tumors, but also microbiology, toxicology, drug discovery, food and environmental industry. But, the limit of FCM is its dependence on operator from sample preparation, instrument settings up to data analysis and a strong effort is now under progress for standardization and constitution of international data bank for references and education.

A case of anti-NMDA receptor encephalitis in a woman with a NMDA-R(+) small cell lung carcinoma (SCLC).

The association of small cell lung cancer with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is rare. We report a 62 year old patient who developed psychiatric disorders followed by epilepsy, movement disorders, mutism and hypoventilation. Flair weighted brain MRI sequences showed diffuse high signals in the limbic system. Anti-NMDAR antibodies were detected in the serum and CSF. The patient's IgGs reacted with the patient's own tumor cells and with 2 out of 4 small cell lung cancers of patients without neurological syndrome.