Role of p16 in the pathogenesis of Langerhans cell histiocytosis

BACKGROUND: It has been hypothesized that genetic alteration at the cellular level may have a significant effect on cellular mechanisms controlling the proliferation and apoptosis of Langerhans cells (LCs). METHODS: We examined whether p16 protein expression can be used to predict the outcome of Langerhans cell histiocytosis (LCH). Archival paraffin blocks from children diagnosed with LCH and followed at the Asan Medical Center and Chungnam National University Hospital between March 1998 and February 2008 were studied. RESULTS: Slides were stained with p16 antibody and evaluated semi-quantitatively using the following scale: negative, no staining; +/-, weakly positive; 1+, staining similar to lymphocytes surrounding the LCs; 2+, stronger staining than lymphocytes; 3+, much stronger staining than lymphocytes. Negative and +/- groups were assigned to a lower expression group (LEG) and the 1+, 2+, and 3+ groups were assigned to a higher expression group (HEG). The median age of the 51 patients (24 girls, 27 boys) was 49 (range, 0.6-178) months, and LCH was diagnosed based on CD1a positivity. p16 protein was expressed to varying degrees in all but one specimen. There was a greater tendency toward multisystem disease, risk organ involvement, and relapse in the HEG than in the LEG. CONCLUSION: The p16 protein may have a significant effect on cellular mechanisms controlling the proliferation and apoptosis of LCs, and thus may influence the clinical outcome and prognosis of LCH.

Analysis of Blood Spot 17-Hydroxyprogesterone Concentration According to Gestational Age and Birth Weight / 대한임상병리학회지

BACKGROUND: High levels of 17-hydroxyprogesterone (17-OHP) are frequently observed in premature infants without congenital adrenal hyperplasia. The purpose of this study is to set cut-off limits of 17-OHP on the basis of gestational age at birth and birth weight. METHODS: Blood spot 17-OHP concentrations were measured in 1,000 infants on the 3th day of life at Inha University Hospital. An enzyme-linked immunosorbent assay (ELISA) method (ICN Neoscreen ELISA 17-hydroxyprogesterone kit, ICN Pharmaceuticals. Inc., Japan) was used. The values obtained were analyzed with respect to birth weight and gestational age at birth in order to decide the appropriate cut-off limits in a neonatal mass screening for 21-hydroxylase deficiency. RESULTS: In the neonatal mass screening for CAH, the cut-off limits for determining the 17-OHP for recall, were decided as follows: (1) 57.65, 39.88, 33.52 ng/mL for gestational age at birth of 35 weeks or less, 36-37, and 38 weeks or more, respectively, and (2) 54.88, 43.86, 32.92 ng/mL for birth weight of 2.49 or less, 2.50-2.99, 3.00 kg or more, respectively. CONCLUSIONS: The cut-off limits on the basis of gestational age at birth and birth weight should be used in the screening for congenital adrenal hyperplasia. We believe that the false positive rate in premature infants can be reduced using this method.

Comparison of High Performance Liquid Chromatography and Fluorescence Polarization Immunoassay for Determination of Total Homocysteine in Human Plasma / 대한임상병리학회지

BACKGROUND: It was purposed to estimate correlation between fluorescence polarization immunoassay (FPIA) and high performance liquid chromatography (HPLC), and precision of individual methods. It was also objected to describe distribution of plasma total homocysteine in Korean adults. METHODS: The subjects were 100 adults admitted to Inha University Hospital during the month of October, 1998. The total plasma homocysteine concentration was measured by FPIA (IMx analyzer, Abbott Laboratories, IL, USA) and by HPLC (ACCLAIM Biogenic Amines Testing System, Bio-Rad Laboratories, CA, USA) using Bio-Rad Homocysteine. RESULTS: Plasma homocysteine levels (mean+/-SD) from Korean healthy adults by FPIA and HPLC were 9.75+/-3.80micromol/L, 7.72+/-3.36micromol/L, respectively. Plasma homocysteine levels according to sex by FPIA were 11.79micromol/L for male, 7.71micromol/L for female, and those by HPLC were 9.47micro mol/L for male, 5.98micromol/L for female, respectively. Intra-assay coefficient variations (CVs) of low, medium, and high concentration by FPIA are 1.83%, 0.47%, and 1.66%, and those by HPLC are 5.53%, 5.37%, and 4.56%, respectively. Inter-assay CVs of low, medium, and high concentration by FPIA are 2.28%, 1.44%, and 1.29%, and by HPLC are 7.23%, 5.54%, and 4.95%, respectively. CONCLUSION: Plasma homocysteine levels from male were significantly higher than female in Korean. Plasma homocysteine levels were increased according to increment of age. FPIA was more convenient, automatic, rapid, and reproducible than HPLC and also excellently correlated with HPLC. It is concluded that FPIA will potentially benefit for quantifying homocysteine in clinical laboratories.