Progesterone induced blocking factor (PIBF) taken in early pregnancy predicts the pregnancy outcome in women undergoing in vitro fertilization procedure.

Earlier data suggest a relationship between PIBF concentrations and the outcome of pregnancy. The aim of the study was to compare serum and urine concentrations of PIBF in women with successful pregnancy after IVF with those of women without pregnancy after IVF procedure, and to evaluate the potential relation between PIBF and the outcome of pregnancy. Urine and serum were collected from 120 women, undergoing IVF. 87.5% of patients had primary infertility. 69.2% faced female causes of infertility: 10.8% tubal cause, 11.7% ovulation disorder, and 46.7% other causes of infertility. 30.8% of patients had male factor of infertility. Among non-pregnant women (42) mean concentrations of PIBF in urine and serum were significantly lower (15.8 ng/mL; 148.4 ng/mL) than in women with positive beta HCG value (78) (19.1 ng/mL; 225.9 ng/mL). In 49 patients pregnancy terminated with a term delivery, in 10 patients with pretem delivery, while in 19 patients the pregnancy terminated with a miscarriage. PIBF concentrations in urine (13.9 ± 2.8 ng/mL) and serum (124.6 ± 46.7 ng/mL) samples of women with miscarriage were significantly lower of those with preterm delivery (180.6 ± 54.4 ng/mL; 18.1 ± 4.4 ng/mL) and of those with term delivery (20.4 ± 8.5 ng/mL; 208.7 ± 114.3 ng/mL). Successful pregnancy after IVF procedure is predictable by measuring of urine and serum PIBF concentrations and could be important for predicting of early implantation and pregnancy outcome after IVF procedure and maybe to protect the risk pregnancy.

Identification of pregnancy-associated glycoprotein family (PAG) in the brown bear (Ursus arctos L.).

Pregnancy-associated glycoproteins (PAGs) are abundant embryo-originated products expressed in the pre-placental trophoblast and, later, in the post-implantational chorionic epithelium of some mammalian species. This paper describes the identification and cellular immunolocalization of the chorionic PAG family in the discoidal-type placenta of the brown bear (Ursus arctos L. - Ua), in which the PAGs were named 'UaPAG-Ls'. The study used: 1) Western blot for total placental glycoproteins; and 2) cross-species heterologous double fluorescent immunohistochemistry (IHC) for cellular immune-localization of the PAGs. This is the first study reporting the identification and immunolocalization of the UaPAG-L family in placental cells during early pregnancy in the brown bear. Our Western analysis revealed a dominant mature 72 kDa UaPAG-L isoform was expressed in all Ua placentas during early pregnancy. Various other UaPAG-L isoforms (16-66 kDa) were also identified. Using IHC, the UaPAG-L proteins were localized to trophectodermal cells (TRD), where signal intensity resembled intense TRD proliferation within developing placenta. The data increases our general knowledge of PAG proteins localized in discoidal-type placenta during early pregnancy in the brown bear.

Lower Urinary and Serum Progesterone-Induced Blocking Factor in Women with Preterm Birth.

The aim of the study was to compare urine and serum concentrations of PIBF at 24-28 gestational weeks in women with preterm birth, with those of women who delivered at term and to evaluate the impact of PIBF on the outcome of pregnancy. Case-control study was performed in period from 1.6.2010-31.7.2013. Biological samples (urine and serum) were collected from 126 pregnant women. All biological samples were obtained at 24-28 gestation weeks. We measured PIBF concentration and compared women who delivered preterm and those who delivered at term. Thirteen of 126 pregnant women (10.3%) who were included in the study delivered preterm. Among women that actually delivered preterm, median concentrations of PIBF were significantly lower (12.3ng/ml; 101.3ng/ml) than in women who delivered at term (77.0ng/ml; 412.7ng/ml). The serum and urine 24-28 gestational weeks PIBF in those who delivered preterm were generally low from 24 to 37 gestational weeks, while the serum and urine PIBF concentration reached a peak in those delivering between 37-38 gestational weeks, even significantly different from those delivering at 39 to 40 and after 40 gestational weeks. Preterm birth may be predictable at 24-28 gestational week by lower than normal pregnancy PIBF values and measurement of PIBF concentration in biological fluids at that time may be of importance in clinical practice.

Plasma PP13 and urinary GAGs/PGs as early markers of pre-eclampsia.

PURPOSE: To evaluate at 11-13 weeks' gestation biochemical markers that may predict complications of pregnancy such as pre-eclampsia, proteinuria, and hypertension. METHODS: Analyses were performed on first-morning urine and plasma samples from first trimester pregnant women with increased risk of developing pre-eclampsia such as positive personal or family history of cardiovascular disease and diabetes mellitus. A total of 62 women were enrolled, 24 of them presented complications such as pre-eclampsia, proteinuria, and hypertension during pregnancy. The remaining 38 women had a physiological course of pregnancy and formed the reference group. Urine glycosaminoglycans/proteoglycans (GAGs/PGs) distribution was determined by electrophoresis on cellulose acetate strips. Urinary N-acetyl-ß-glucosaminidase was estimated kinetically. Plasma levels of placental protein 13 (PP13) were measured by enzyme-linked immunosorbent assay. RESULTS: No significant differences in total GAG excretion and N-acetyl-ß-glucosaminidase (NAG) concentration were observed between the two groups of pregnant women, whereas we detected increased relative content of total urinary trypsin inhibitor (UTI plus low-sulfated chondroitin sulfate) (p = 0.001) and reduced excretion of heparan sulfate (p = 0.007) and chondroitin sulfate (p = 0.011) in women presenting with pregnancy complications respect to controls. Plasma levels of PP13 were significantly reduced in the group of women who went on to develop complications compared with controls (p = 0.022). CONCLUSIONS: The reduced plasma levels of PP13 and the alteration of the relative content of urinary GAGs and PGs observed in our study could be a promising tool for the prediction of pre-eclampsia in an early stage of pregnancy.

Accuracy of angiogenic biomarkers at ⩽20weeks' gestation in predicting the risk of pre-eclampsia: A WHO multicentre study.

OBJECTIVE: To assess the accuracy of angiogenic biomarkers to predict pre-eclampsia. DESIGN: Prospective multicentre study. From 2006 to 2009, 5121 pregnant women with risk factors for pre-eclampsia (nulliparity, diabetes, previous pre-eclampsia, chronic hypertension) from Argentina, Colombia, Peru, India, Italy, Kenya, Switzerland and Thailand had their serum tested for sFlt-1, PlGF and sEng levels and their urine for PlGF levels at ⩽20, 23-27 and 32-35weeks' gestation (index tests, results blinded from carers). Women were monitored for signs of pre-eclampsia, diagnosed by systolic blood pressure ⩾140mmHg and/or diastolic blood pressure ⩾90mmHg, and proteinuria (protein/creatinine ratio ⩾0.3, protein ⩾1g/l, or one dipstick measurement ⩾2+) appearing after 20weeks' gestation. Early pre-eclampsia was defined when these signs appeared ⩽34weeks' gestation. MAIN OUTCOME MEASURE: Pre-eclampsia. RESULTS: Pre-eclampsia was diagnosed in 198 of 5121 women tested (3.9%) of whom 47 (0.9%) developed it early. The median maternal serum concentrations of index tests were significantly altered in women who subsequently developed pre-eclampsia than in those who did not. However, the area under receiver operating characteristics curve at ⩽20weeks' gestation were closer to 0.5 than to 1.0 for all biomarkers both for predicting any pre-eclampsia or at ⩽34weeks' gestation. The corresponding sensitivity, specificity and likelihood ratios were poor. Multivariable models combining sEng with clinical features slightly improved the prediction capability. CONCLUSIONS: Angiogenic biomarkers in first half of pregnancy do not perform well enough in predicting the later development of pre-eclampsia.

Urinary excretion of C5b-9 is associated with the anti-angiogenic state in severe preeclampsia.

PROBLEM: Severe preeclampsia has been independently linked to complement dysregulation and angiogenic imbalance; however, the relationship between complement and angiogenic factors in human pregnancy is unclear. METHOD OF STUDY: Utilizing existing biomarkers, our study sought to better understand this relationship in active disease. We performed a case-control study, enrolling 25 cases with severe preeclampsia, 25 controls with chronic hypertension, and 25 healthy controls without hypertension. Levels of complement components (C3a, C5a, and C5b-9) and angiogenic markers [basic fibroblast growth factor (bFGF), placental growth factor (PlGF), vascular endothelial growth factor (VEGF), and soluble fms-like tyrosine kinase-1 (sFlt-1)] were measured simultaneously. RESULTS: Compared to both hypertensive and non-hypertensive controls, severe preeclampsia was associated with increased plasma sFlt-1, decreased plasma VEGF and PlGF, decreased urinary PlGF, and increased urinary C5b-9. Urinary marker C5b-9 correlated strongly with the anti-angiogenic condition. In subjects with detectable urinary excretion of C5b-9, median plasma levels of sFlt-1 were significantly greater (32,029 versus 4556 pg/mL, P < 0.0001) and levels of PlGF (15.6 versus 226 pg/mL, P < 0.0001) and VEGF (119 versus 153 pg/mL, P = 0.001) were significantly lower. CONCLUSION: More so than plasma complement markers, urinary C5b-9 may a useful measure to link complement dysregulation with angiogenic imbalance in severe preeclampsia.

Arsenite-mediated promotion of anchorage-independent growth of HaCaT cells through placental growth factor.

Various cancers including skin cancer are increasing in 45 million people exposed to arsenic above the World Health Organization's guideline value of 10 µg l(-1). However, there is limited information on key molecules regulating arsenic-mediated carcinogenesis. Our fieldwork in Bangladesh demonstrated that levels of placental growth factor (PlGF) in urine samples from residents of cancer-prone areas with arsenic-polluted drinking water were higher than those in urine samples from residents of an area that was not polluted with arsenic. Our experimental study in human nontumorigenic HaCaT skin keratinocytes showed that arsenite promoted anchorage-independent growth with increased expression and secretion of PlGF, a ligand of vascular endothelial growth factor receptor1 (VEGFR1), and increased VEGFR1/mitogen-activated protein kinase/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) activities. The arsenite-mediated promotion of anchorage-independent growth was strongly inhibited by PlGF depletion with decreased activities of the PlGF/VEGFR1/MEK/ERK pathway. Moreover, arsenite proteasome-dependently degrades metal-regulatory transcription factor-1 (MTF-1) protein, resulting in a decreased amount of MTF-1 protein binding to the PlGF promoter. MTF-1 negatively controlled PlGF transcription in HaCaT cells, resulting in increased PlGF transcription. These results suggest that arsenite-mediated MTF-1 degradation enhances the activity of PlGF/VEGFR1/MEK/ERK signaling, resulting in promotion of the malignant transformation of keratinocytes. Thus, this study proposed a molecular mechanism for arsenite-mediated development of skin cancer.

The relationship of angiogenic factors to maternal and neonatal manifestations of early-onset and late-onset preeclampsia.

OBJECTIVE: An imbalance between angiogenic and antiangiogenic factors has been implicated in the pathogenesis and severity of preeclampsia. In this study, we evaluated serum levels of an angiogenic factor and an antiangiogenic factor - placental growth factor (PlGF) and soluble fms-like tyrosine kinase 1 (sFlt-1), respectively - in pregnant women with preeclampsia, as well as evaluating the impact of those factors on maternal and fetal outcomes. METHOD: We studied 44 pregnant women diagnosed with preeclampsia and admitted to an intensive care unit (ICU). The preeclampsia was classified (by weeks of gestation at delivery) as early-onset (<34 weeks) or late-onset (≥34 weeks). We analyzed serum PlGF and sFlt-1, as well as urinary PlGF at admission to the ICU. RESULTS: In the early-onset preeclampsia group, the sFlt-1/PlGF ratio was higher, as was serum sFlt-1, whereas serum PlGF was lower. Serum sFlt-1 and the sFlt-1/PlGF ratio correlated positively with proteinuria and length of maternal hospital stay and correlated negatively with birth weight. The sFlt-1/PlGF ratio correlated positively with length of newborn stay in the neonatal ICU. CONCLUSION: Angiogenic imbalance is more pronounced in patients with early-onset preeclampsia and correlates with worse clinical outcomes, especially for the neonates.

Effects of angiogenic factors, antagonists, and podocyte injury on development of proteinuria in preeclampsia.

Proteinuria is universal to all patients with preeclampsia. We examined the urinary podocytes in women with preeclampsia (n = 14), gestational hypertension (n = 14), and normal pregnancy. Maternal serum and urinary concentrations of vascular endothelial growth factor (VEGF), placental growth factor (PlGF), and the antiangiogenic factor soluble fms-like tyrosine kinase 1 (sFlt-1) were detected. These concentrations were used to evaluate the urinary excretion of podocytes and the alteration of angiogenic factors and to assess their relationships to proteinuria in preeclampsia. Our studies suggest that the urinary podocyte number and angiogenic factors are correlated with random urine albumin/creatinine ratio and blood pressure. Receiver-operating characteristic (ROC) curves of serum and urinary PlGF and the PlGF/sFlt-1 ratio as well as the presence of podocyturia confirmed their usefulness in distinguishing preeclamptic and normotensive pregnant women. In addition, combinations of serum or urinary PlGF or podocyturia tests in parallel or in series provided the best clue for identifying patients with preeclampsia. We considered that the dysregulation of angiogenic factors and its subsequent podocyte injury may contribute to the mechanism of proteinuria development in preeclampsia.

Review: Biochemical markers to predict preeclampsia.

Worldwide the prevalence of preeclampsia (PE) ranges from 3 to 8% of pregnancies. 8.5 million cases are reported yearly, but this is probably an underestimate due to the lack of proper diagnosis. PE is the most common cause of fetal and maternal death and yet no specific treatment is available. Reliable biochemical markers for prediction and diagnosis of PE would have a great impact on maternal health and several have been suggested. This review describes PE biochemical markers in general and first trimester PE biochemical markers specifically. The main categories described are angiogenic/anti-angiogenic factors, placental proteins, free fetal hemoglobin (HbF), kidney markers, ultrasound and maternal risk factors. The specific biochemical markers discussed are: PAPP-A, s-Flt-1/PlGF, s-Endoglin, PP13, cystatin-C, HbF, and α1-microglobulin (A1M). PAPP-A and HbF both show potential as predictive biochemical markers in the first trimester with 70% sensitivity at 95% specificity. However, PAPP-A is not PE-specific and needs to be combined with Doppler ultrasound to obtain the same sensitivity as HbF/A1M. Soluble Flt -1 and PlGF are promising biochemical markers that together show high sensitivity from the mid-second trimester. PlGF is somewhat useful from the end of the first trimester. Screening pregnant women with biochemical markers for PE can reduce unnecessary suffering and health care costs by early detection of mothers at increased risk for PE, thus avoiding unnecessary hospitalization of pregnant women with suspect or mild PE and enabling monitoring of the progression of the disease thereby optimizing time for delivery and hopefully reducing the number of premature births.

Changes of progesterone-induced blocking factor in patients after kidney transplantation.

The prediction of graft rejection can play an important part in graft survival. Analysis of immune reactions has shown that graft rejection shares mechanisms with recurrent abortions during pregnancy. Progesterone-induced blocking factor (PIBF), a mediator of progesterone that blocks natural killer cell activity in peripheral blood, produces antiabortive effects. The aim of this study was to examine the PIBF concentration in the urine of transplanted recipients. The study included 116 white adults (70 men and 46 women) of median age 49.3 years, who had undergone kidney transplantations. The median duration after transplantation was 3.46 years. The average period between renal disease and our measurement was 12.3 years, and the median interval between graft rejection and our study was 1.75 years. Urine samples were used to measure PIBF concentrations by an enzyme-linked immunsorbent assay. PIBF urinary concentrations decreased significantly in patients who experienced ≥1 rejection episode (31.8±2.2 ng/mL) compared with those without any episode (22.7±1.2 ng/ml; P<.01). Moreover, the urinary PIBF level was significantly lower among patients who had increased creatinine and urea nitrogen levels in blood samples (P<.05 and P<.01, respectively). Decreased PIBF values in kidney transplant patients followed previous rejection episodes. A close negative correlation was observed between urinary PIBF concentrations and blood levels of creatinine and urea nitrogen. These findings suggested that PIBF detection may predict graft rejection in transplant recipients.

Urinary placental growth factor differentiates the hypertensive disorders of pregnancy.

AIMS: To evaluate the discriminating capacity of urinary placental growth factor (uPlGF) for different hypertensive diseases of pregnancy during the third trimester. METHODS: A prospective descriptive case-control study conducted in an urban tertiary referral hospital and district general hospital, Sydney South West Area Health Service, Australia. Inpatients and outpatients with and without hypertension in the third trimester were recruited. Eligible patients provided a urine sample for protein, creatinine and a uPlGF level by ELISA. Patients were categorised into clinical hypertensive groups based on the diagnostic criteria of SOMANZ. RESULTS: Eighty-eight women were evaluated; 41 had hypertension (15 pre-eclampsia; 13 gestational hypertension; eight chronic hypertension; five pre-eclampsia superimposed on chronic hypertension) and 47 women without hypertension as the control group. There was a significant difference in uPlGF levels between the pre-eclamptic group (median 2.56 IQR 1.12-4.51) and the normotensive controls (median 13.18 IQR 5.95-31.39) (P < 0.0001); the gestational hypertensive group (median 3.74 IQR 2.49-4.91) and the normotensive group (median 13.18 IQR 5.95-31.39) (P=0.002) and for a subgroup comparison of placental-mediated hypertension (median 2.75 IQR 1.38-4.82) versus non-placental-mediated hypertensives (median 6.96 IQR 3.87-12.54) (P=0.007). CONCLUSIONS: Urinary placental growth factor is a simple non-invasive test, which is discriminatory for pre-eclampsia in the third trimester of pregnancy. Results from this study indicate that it may be discriminatory for hypertension related to placental dysfunction (pre-eclampsia and gestational hypertension) when compared with hypertension unrelated to placental function. Further work is required to assess the ability to detect hypertensive diseases before they are clinically apparent.

Placental growth factor in patients with decreased renal function.

BACKGROUND: Patients with decreased renal function are characterized by high cardiovascular morbidity and mortality due to complications of premature atherosclerosis. Placental growth factor (PlGF) is a proatherogenic cytokine and new biomarker of cardiovascular events. The aim of this study was to determine PlGF levels and describe their relationship to renal function and risk factors of atherogenesis in patients with decreased renal function. METHODS: The study group consisted of 114 subjects: 45 patients with various degrees of decreased renal function (CHRI), 31 long-term hemodialysis (HD) patients, and 38 age-matched healthy control subjects. PlGF was assessed immunochemically (enzyme-linked immunosorbent assay) and routine biochemical parameters were measured using standard laboratory methods. RESULTS: PlGF levels were significantly increased in CHRI and HD patients compared to controls (10.5 ± 3.3 pg/mL in CHRI patients and 11.5 ± 3.4 pg/mL HD patients vs. 8.1 ± 1.8 pg/mL in controls, both p < 0.0001). In CHRI patients, PlGF was detectable in the urine, and its urine concentration correlated with its serum levels. In HD patients, PlGF correlated with low-density lipoproteins (r = 0.36, p < 0.05), but was not related to C-reactive protein levels. Higher levels of PlGF were found in CHRI patients with cardiovascular disease, compared with those free of such complication. CONCLUSIONS: PlGF levels are increased in patients with decreased kidney function. PlGF is detectable in the urine, and serum and urine levels of PlGF are significantly interrelated. It is higher in CHRI patients with cardiovascular disease. Further studies are required to demonstrate the usefulness and significance of PlGF in patients with chronic kidney disease.

Early pregnancy maternal serum PAPP-A and urinary protein-creatinine ratio as predictive markers of pregnancy induced hypertension.

Pregnancy induced hypertension (PIH) is a major complication of pregnancy and is associated with high maternal and perinatal morbidity and mortality. The aim of this study was to investigate the possible causal association of PIH with maternal serum PAPP-A and urinary protein-creatinine ratio (UPCr) as well as to evaluate the usefulness of these two variables as predictive markers of PIH. A total 200 women of 8-16 weeks of pregnancy were enrolled in this study. All the patients were followed up till delivery for the development of pregnancy induced hypertension. Thirty patients were lost in the follow up, 3(1.76%) developed preeclampsia (PE) and 14(8.23%) gestational hypertension (GH). By a nested case-control design the 17 pregnancy induced hypertension cases were compared with 48 Controls with normal pregnancy outcome. Maternal serum PAPP-A was significantly lower in the pregnancy induced hypertension group compared to Control [mIU/ml, median (range) 1.8(0.70-4.1) vs. 5.45(2.7-10), p<0.001]. UPCr was significantly higher in the pregnancy induced hypertension group compared to Control (mg/mmol, mean+/-SD, 6.86+/-1.56 vs. 4.75+/-0.96, p<0.001). When tested as a predictive marker of pregnancy induced hypertension the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of maternal serum PAPP-A in the lowest 25th percentile were 82%, 95%, 87% and 93%. At 75th percentile the sensitivity, specificity, PPV and NPV of UPCr were 52%, 85%, 56% and 83% respectively.

Progesterone - induced blocking factor (PIBF) and Th(1)/Th(2) cytokine in women with threatened spontaneous abortion.

OBJECTIVE: The aim of this prospective study was to compare serum and urine concentrations of progesterone-induced blocking factor (PIBF) and serum concentrations of anti-inflammatory (IL10) and pro-inflammatory (IL6, TNFalpha, IFNgamma) cytokines of women with threatened spontaneous abortion with normal pregnancy and to evaluate the impact of PIBF on outcome of pregnancy. METHODS: A sample of 30 women with threatened spontaneous abortion (study group) and 20 healthy pregnant women (control group) between 6(th) and 24(th) gestational weeks was studied. Serum and urine PIBF, IL10 and IL6, TNFalpha, IFNgamma cytokine concentrations were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Five (16.7%) pregnancies in the study group ended missed abortion vs. none in the control group (P<0.05). Five (20%) threatened aborters delivered between 24(th) and 37(th) weeks of gestation, whereas two (10%) preterm deliveries occurred in the controls (P>0.05). PIBF concentrations in urine (19.5+/-12.9 ng/mL) and serum (214.4+/-120.6 of patients with threatened abortion were significantly lower than in healthy pregnant women (45.3+/-33.7 ng/mL and 357.3+/-159.9 ng/mL, respectively). Women with threatened abortion had significantly lower serum levels of anti-inflammatory cytokine, but levels of proinflammatory cytokines were higher in this group compared with healthy controls. CONCLUSIONS: Determination of progesteron-induced blocking factor level in body fluids in early pregnancy might be used for the diagnosis and prognosis of threatened abortion.

First trimester urinary placental growth factor and development of pre-eclampsia.

OBJECTIVE: To compare urinary placental growth factor (PlGF) concentration at 11(+0) to 13(+6) weeks of gestation in women who subsequently develop pre-eclampsia with normotensive controls. DESIGN: Nested case-control study within a prospective study for first trimester prediction of pre-eclampsia. SETTING: Routine antenatal visit in a teaching hospital. POPULATION: Fifty-two women who developed pre-eclampsia and 52 controls matched for gestational age and sample storage time. METHODS: Urinary PlGF concentration and PlGF to creatinine ratio were measured in women who developed pre-eclampsia and their matched controls. Comparisons between groups were performed using Student's t test. MAIN OUTCOME MEASURES: Development of pre-eclampsia. RESULTS: In the pre-eclampsia group, the median urinary PlGF concentration (20.6 pg/ml, interquartile range [IQR] 9.1-32.0 pg/ml) and median urinary PlGF to creatinine ratio (1.6 pg/mg, IQR 1.2-2.5 pg/mg) were not significantly different from the control group (11.8 pg/ml, IQR 5.5-29.8 pg/ml, P=0.1 and 1.7 pg/mg, IQR 1.2-2.3 pg/mg, P=0.3, respectively). There were no significant differences between women with early-onset pre-eclampsia requiring delivery before 34 weeks (n=13) and those with late-onset pre-eclampsia (n=39) and between women with pre-eclampsia and fetal growth restriction (FGR) (n=25) and those with pre-eclampsia and no FGR (n=27) in either median PlGF concentration or median urinary PlGF to creatinine ratio. CONCLUSIONS: The development of pre-eclampsia is not preceded by altered urinary PlGF concentration in the first trimester of pregnancy.

Human trophoblast cells express the immunomodulator progesterone-induced blocking factor.

Progesterone-induced blocking factor (PIBF) is an immunomoduatory factor with anti-abortive properties. In this study, we present evidence that PIBF is synthesized in the human placenta and determine its cellular source. Expression of PIBF was analysed with polyclonal rabbit anti-human PIBF antibodies against recombinant N-terminal 48kDa PIBF in first trimester and term placental tissues and in the choriocarcinoma cell line JAR by means of immunohistochemistry, confocal laser scanning microscopy of double immunofluorescence labelling, and Western blotting; RT-PCR was performed for analysis of PIBF mRNA in isolated trophoblast cells. PIBF protein is present in human first trimester and term placenta. Double immunofluorescence labelling localised PIBF to the extravillous cytotrophoblast. PIBF is also expressed heterogeneously by syncytiotrophoblast and part of the villous cytotrophoblast. Full-length PIBF mRNA encoded by exons 1-18 is present in isolated first trimester and term villous trophoblast and in the choriocarcinoma cell line JAR. The corresponding 90kDa protein is expressed by JAR cells, first trimester and term villous trophoblast cells. In addition, these cells express PIBF proteins of 50 and 34kDa. Trophoblast is a source of PIBF; its tissue distribution suggests a role both in systemic and local (decidual) immunoregulation.

Production and characterization of a novel monoclonal antibody against progesterone-induced blocking factor (PIBF).

Progesterone-induced blocking factor (PIBF) has been described as an active factor intimately involved in regulation of the immune response in pregnancy. It has been shown that PIBF biased the cytokine balance to Th2-type in pregnancy and inhibited the activity of NK cells. The biological roles of PIBF would be better defined if methods for its detection and measurement in biological fluids are available. However, so far, reliable antibodies have not been developed to be used as specific probes. A monoclonal antibody designated as MAB 3A6 was produced and characterized. MAB 3A6 reacts specifically with PIBF. It can detect this protein in biological fluids when tested by immunoblot and recognizes PIBF expressed on the surface of lymphocytes of pregnant women stimulated in vitro with progesterone. The characteristics of MAB 3A6 makes it the possible basis for development of a clinically applicable assay to assess the presence and concentration of PIBF in biological samples.

Major basic protein homolog (MBP2): a specific human eosinophil marker.

Human eosinophil granule major basic protein (MBP1) is an exceedingly basic (isoelectric point >11) 14-kDa protein, comprising the core of the secondary eosinophil granule. Recently, a less cationic homolog of MBP, termed MBPH or simply, MBP2, has been discovered. We prepared a panel of mAbs to MBP2 and used these Abs to localize and quantitate this molecule in leukocytes and biological fluids. Specific mAbs for MBP2 were selected using slot-blot analyses and used in a two-site immunoassay, Western blotting, and immunofluorescence microscopy. The sensitivity of the immunoassay was markedly improved by reduction and alkylation of MBP2. MBP1 is more abundant than MBP2 in lysates of eosinophils and their granules, as judged by immunoassay and Western blotting. By immunofluorescence, MBP1 is present in eosinophils, basophils, and a human mast cell line (HMC1), whereas MBP2 is only detected in eosinophils. Neither MBP1 nor MBP2 could be detected in any other peripheral blood leukocyte. MBP2 levels measured in plasma and serum were essentially identical. In contrast to past measurements for MBP1, MBP2 was not detected above normal levels in sera from pregnant donors. However, measurement of serum MBP2 discriminated patients with elevated eosinophils from normal subjects, and MBP2 was also detectable in other biological specimens, such as bronchoalveolar lavage, sputum, and stool. These results indicate that MBP2 is present only in eosinophils and that it may be a useful biomarker for eosinophil-associated diseases.

Low urinary placental growth factor is a marker of pre-eclampsia.

Recent reports of increased serum levels of soluble fms-like tyrosine kinase 1 (sFlt-1) and decreased levels of placental growth factor (PlGF) suggest the key role of angiogenic factors in development of pre-eclampsia. PlGF is excreted in urine, and reduced urinary level has been suggested as a marker of this condition as well as help in its prediction. We measured urinary PlGF and creatinine values in 69 pregnant women (35 with pre-eclampsia and 34 normotensive controls). Over 70% patients had severe pre-eclampsia. Compared to controls, the urinary PlGF and PlGF/creatinine levels were significantly reduced in women with pre-eclampsia. The hospital stay was longer and fetal outcomes poorer in this group. Three normotensive women who showed very low levels developed pre-eclampsia 2-6 weeks later. Reduced urinary PlGF level in a pregnant woman is a marker of pre-eclampsia. The value of reduced urinary PlGF levels in predicting pre-eclampsia in currently normotensive pregnant women needs to be evaluated. A simple predictive test is likely to be of value in the developing countries.