Prediction of ABO hemolytic disease of the newborn using pre- and perinatal quantification of maternal anti-A/anti-B IgG titer.

BACKGROUND: Hemolysis in fetus/newborns is often caused by maternal antibodies. There are currently no established screening procedures for maternal ABO antibodies harmful to fetus/newborn. We investigated the clinical significance, and predictive value of maternal anti-A/B titer for hyperbilirubinemia in ABO-incompatible newborns. METHODS: We conducted a case-control study of blood group O mothers and their ABO-compatible (O) vs. -incompatible (A/B) newborns receiving phototherapy, and of ABO-incompatible newborns receiving phototherapy vs. no phototherapy. Newborn data and treatment modalities were recorded, and total serum bilirubin and hemoglobin were measured. Maternal anti-A/B immunoglobulin-γ (IgG) titers were measured prenatally and perinatally, and negative and positive predictive values (NPV, PPV) were calculated to assess the risk of developing hyperbilirubinemia requiring phototherapy. RESULTS: We found a significantly higher maternal IgG antibody titer in the case group (p < 0.001). Maternal anti-A/B titers at first trimester had modest predictive values: NPV = 0.82 and PPV = 0.65 for neonatal hyperbilirubinemia; titers at birth improved the predictive values: NPV = 0.93 and PPV = 0.73. Newborn hemoglobin was significantly lower in incompatibles compared to compatibles (p = 0.034). Furthermore, increased anti-A/B IgG production during pregnancy was associated with hyperbilirubinemia and hemolysis in incompatible newborns. CONCLUSIONS: There was a significant association between maternal anti-A/B IgG titer and hyperbilirubinemia requiring treatment. IMPACT: Maternal anti-A/B IgG titer in the first trimester and at birth is predictive of hemolytic disease of the ABO-incompatible newborn. Increased IgG anti-A/B production throughout pregnancy in mothers to ABO-incompatible newborns developing hyperbilirubinemia contrasts a constant or reduced production in mothers to newborns not developing hyperbilirubinemia. Screening tools available in most immunohematology laboratories can identify clinically important IgG anti-A/B. Use of maternal samples taken at birth yielded NPV = 0.93 and PPV = 0.73.

Managing patients on direct factor Xa inhibitors with rapid thrombelastography.

The use of direct factor Xa inhibitors rivaroxaban and apixaban (XABANs) has rapidly increased; however, there is no validated test available to monitor the effect on hemostasis. This study aims to assess how hemostatic management based on the Rapid Thromboelastography (R-TEG) variable activated clotting time (ACT) of XABAN patients with ongoing bleedings or in need for acute surgical intervention, affected patient outcome. A total of 343 XABAN patients were included in the main analysis together with 50 healthy volunteers to validate the reference value for ACT. An ACT >120 s (s) was defined as having XABAN-induced coagulopathy. Sixty-five percent of the XABAN patients presented with R-TEG ACT within the normal reference. Patients with XABAN-induced coagulopathy had a significantly increased risk of severe bleeding. Significantly more patients with extra-cerebral bleeding (ECB) and ACT above 120 s were transfused with five red blood cell (RBC) units or more compared to patients with ACT at 120 s or below (17% vs. 3%, p <.05). Significantly more XABAN-patients with ACT above 120 s received pro-hemostatic intervention with prothrombin complex concentrate (PCC) when compared to those with ACT at 120 s or below (ECB: 2% vs. 8%, p =.03, intracranial hemorrhage: 25% vs. 68%, p <.00). Patients who received PCC had a higher 30- and 90-day mortality compared to the rest of the cohort (16% vs. 6%, p = .02 and 21% vs. 7%, p =.00). Patients with XABAN-induced coagulopathy as evaluated by R-TEG ACT presented with more severe bleeding and higher transfusion requirements when compared to those with ACT in the normal range. This suggests that R-TEG ACT measurement in XABAN patients with active hemorrhage or in need for acute surgery may be of clinical value.

Targeted Rhesus immunoglobulin for RhD-negative women undergoing an induced abortion: A clinical pilot study.

INTRODUCTION: The aim of this clinical pilot study was to examine the accuracy of noninvasive fetal RHD genotyping in early pregnancy (8+0  to 11+6  weeks) and to clarify whether targeted administration of Rhesus immunoglobulin (RhIg) is possible for women undergoing an induced abortion such that unnecessary injections can be avoided. The study examines the correlation between gestational age and the amount of cell-free fetal DNA in maternal plasma, the fetal fraction of DNA and whether transportation time or body mass index affects these parameters. MATERIAL AND METHODS: Fifty-two RhD-negative women undergoing a surgically induced abortion were included. A maternal blood sample was collected prior to the abortion and a tissue sample was collected from the placental part of the abortion material after the intervention. Fetal RhD type was determined by PCR analysis of cell-free fetal DNA extracted from maternal plasma and on DNA from the tissue sample, with the latter providing a reference standard. Copies of RHD/mL were determined on RHD-positive samples and the fetal fraction of DNA was calculated. RESULTS: We demonstrated complete concordance between results from plasma and tissue, with 31 RhD-positive and 21 RhD-negative samples, corresponding to 40% being RhD-negative, specificity 100% [95% confidence interval (CI) 88.8-100] and sensitivity 100% (95% CI 83.9-100). We found no significant correlation between gestational age and the amount or the fraction of cell-free fetal DNA in maternal plasma, nor did we find that transportation time or BMI significantly affected these factors in this setup. CONCLUSIONS: Fetal RHD genotyping can be accurately performed from the 8th week of gestation and unnecessary injections of RhIg can be avoided for women undergoing an induced abortion. A larger study is needed to determine a more accurate sensitivity for the analysis early in pregnancy.

Congenital sideroblastic anemia due to mutations in the mitochondrial HSP70 homologue HSPA9.

The congenital sideroblastic anemias (CSAs) are relatively uncommon diseases characterized by defects in mitochondrial heme synthesis, iron-sulfur (Fe-S) cluster biogenesis, or protein synthesis. Here we demonstrate that mutations in HSPA9, a mitochondrial HSP70 homolog located in the chromosome 5q deletion syndrome 5q33 critical deletion interval and involved in mitochondrial Fe-S biogenesis, result in CSA inherited as an autosomal recessive trait. In a fraction of patients with just 1 severe loss-of-function allele, expression of the clinical phenotype is associated with a common coding single nucleotide polymorphism in trans that correlates with reduced messenger RNA expression and results in a pseudodominant pattern of inheritance.

High-throughput tri-colour flow cytometry technique to assess Plasmodium falciparum parasitaemia in bioassays.

BACKGROUND: Unbiased flow cytometry-based methods have become the technique of choice in many laboratories for high-throughput, accurate assessments of malaria parasites in bioassays. A method to quantify live parasites based on mitotracker red CMXRos was recently described but consistent distinction of early ring stages of Plasmodium falciparum from uninfected red blood cells (uRBC) remains a challenge. METHODS: Here, a high-throughput, three-parameter (tri-colour) flow cytometry technique based on mitotracker red dye, the nucleic acid dye coriphosphine O (CPO) and the leucocyte marker CD45 for enumerating live parasites in bioassays was developed. The technique was applied to estimate the specific growth inhibition index (SGI) in the antibody-dependent cellular inhibition (ADCI) assay and compared to parasite quantification by microscopy and mitotracker red staining. The Bland-Altman analysis was used to compare biases between SGI estimated by the tri-colour staining technique, mitotracker red and by microscopy. RESULTS: CPO allowed a better separation between early rings and uRBCs compared to mitotracker red resulting in a more accurate estimate of total parasitaemia. The tri-colour technique is rapid, cost effective and robust with comparable sensitivity to microscopy and capable of discriminating between live and dead and/or compromised parasites. Staining for CD45 improved parasitaemia estimates in ADCI assay since high numbers of leucocytes interfered with the accurate identification of parasitized RBC. The least bias (-1.60) in SGI was observed between the tri-colour and microscopy. CONCLUSION: An improved methodology for high-throughput assessment of P. falciparum parasitaemia under culture conditions that could be useful in different bioassays, including ADCI and growth inhibition assays has been developed.

The malaria vaccine candidate GMZ2 elicits functional antibodies in individuals from malaria endemic and non-endemic areas.

BACKGROUND: GMZ2 is a hybrid protein consisting of the N-terminal region of the glutamate-rich protein fused in frame to the C-terminal region of merozoite surface protein 3 (MSP3). GMZ2 formulated in Al(OH)3 has been tested in 3 published phase 1 clinical trials. The GMZ2/alum formulation showed good safety, tolerability, and immunogenicity, but whether antibodies elicited by vaccination are functional is not known. METHODS: Serum samples prior to vaccination and 4 weeks after the last vaccination from the 3 clinical trials were used to perform a comparative assessment of biological activity against Plasmodium falciparum. RESULTS: We showed that the maximum level of immunoglobulin G (IgG) antibodies obtained by GMZ2 vaccination is independent of ethnicity, time under malaria-exposure, and vaccine dose and that GMZ2 elicits high levels of functionally active IgG antibodies. Both, malaria-naive adults and malaria-exposed preschool children elicit vaccine-specific antibodies with broad inhibitory activity against geographically diverse P. falciparum isolates. Peptide-mapping studies of IgG subclass responses identified IgG3 against a peptide derived from MSP3 as the strongest predictor of antibody-dependent cellular inhibition. CONCLUSIONS: These findings suggest that GMZ2 adjuvanted in Al(OH)3 elicits high levels of specific and functional antibodies with the capacity to control parasite multiplication.

Evaluating the inhibition of IL-17A and TNFα in a cartilage explant model cultured with Th17-derived cytokines.

Introduction: T-helper 17 (Th17) cells produce IL-17A playing a critical role in activating the pathogenic chain leading to joint tissue inflammation and destruction. Elevated levels of Th17 cells and IL-17A have been detected in skin lesions, blood, and synovial fluid from patients with psoriatic arthritis (PsA) and ankylosing spondylitis (AS). Moreover, IL-17A inhibitors suppress disease activity in psoriasis, PsA and AS, supporting the evidence of IL-17A contributing to the disease pathogenesis. Although, IL-17A inhibitors are widely approved, it remains unclear how the inhibitory effect of IL-17A alters the extracellular matrix (ECM) of the joint in a Th17-conditioned inflammatory milieu. Therefore, the aim of this study was to establish a cartilage model cultured with conditioned medium from Th17 cells and inhibitors to explore the effect of IL-17A inhibition on joint tissue remodeling. Methods: Naïve CD4+ T cells from healthy human buffy coat were differentiated into Th17 cells, followed by Th17 cell activation to secrete Th17-related cytokines and molecules into media. The activated Th17 cells were isolated from the conditioned media (CM) and analyzed using flow cytometry to verify Th17 cell differentiation. The CM were assessed with ELISA to quantify the concentrations of cytokines secreted into the media by the Th17 cells. Healthy bovine cartilage explants were cultured with the Th17-CM and treated with IL-17A and TNFα inhibitors for 21 days. In harvested supernatant from the cartilage cultures, MMP- and ADAMTS-mediated biomarker fragments of type II collagen, aggrecan, and fibronectin were measured by ELISA to investigate the ECM remodeling within the cartilage tissue. Results: Th17-CM stimulated a catabolic response in the cartilage. Markers of type II collagen and aggrecan degradation were upregulated, while anabolic marker of type II collagen formation remained on similar levels as the untreated explants. The addition of IL-17A inhibitor to Th17-CM decreased the elevated type II collagen and aggrecan degradation, however, degenerative levels were still elevated compared to untreated group. The addition of TNFα inhibitor completely reduced both type II collagen and aggrecan degradation compared to untreated explants. Moreover, the TNFα inhibitor treatment did not alter the type II collagen formation compared to untreated group. Conclusion: This study suggests that inhibition of IL-17A in Th17-conditioned cartilage tissue only partially reduced the MMP-mediated type II collagen degradation and ADAMTS-mediated aggrecan degradation, while the TNFα inhibitor treatment fully reduced both MMP- and ADAMTS-mediated ECM degradation. This exploratory study where ECM biomarkers are combined with Th17-conditioned ex vivo model may hold great potential as output for describing joint disease mechanisms and predicting structural effects of treatment on joint tissue.

SMIM1 absence is associated with reduced energy expenditure and excess weight.

BACKGROUND: Obesity rates have nearly tripled in the past 50 years, and by 2030 more than 1 billion individuals worldwide are projected to be obese. This creates a significant economic strain due to the associated non-communicable diseases. The root cause is an energy expenditure imbalance, owing to an interplay of lifestyle, environmental, and genetic factors. Obesity has a polygenic genetic architecture; however, single genetic variants with large effect size are etiological in a minority of cases. These variants allowed the discovery of novel genes and biology relevant to weight regulation and ultimately led to the development of novel specific treatments. METHODS: We used a case-control approach to determine metabolic differences between individuals homozygous for a loss-of-function genetic variant in the small integral membrane protein 1 (SMIM1) and the general population, leveraging data from five cohorts. Metabolic characterization of SMIM1-/- individuals was performed using plasma biochemistry, calorimetric chamber, and DXA scan. FINDINGS: We found that individuals homozygous for a loss-of-function genetic variant in SMIM1 gene, underlying the blood group Vel, display excess body weight, dyslipidemia, altered leptin to adiponectin ratio, increased liver enzymes, and lower thyroid hormone levels. This was accompanied by a reduction in resting energy expenditure. CONCLUSION: This research identified a novel genetic predisposition to being overweight or obese. It highlights the need to investigate the genetic causes of obesity to select the most appropriate treatment given the large cost disparity between them. FUNDING: This work was funded by the National Institute of Health Research, British Heart Foundation, and NHS Blood and Transplant.

Flow cytometric readout based on Mitotracker Red CMXRos staining of live asexual blood stage malarial parasites reliably assesses antibody dependent cellular inhibition.

BACKGROUND: Functional in vitro assays could provide insights into the efficacy of malaria vaccine candidates. For estimating the anti-parasite effect induced by a vaccine candidate, an accurate determination of live parasite count is an essential component of most in vitro bioassays. Although traditionally parasites are counted microscopically, a faster, more accurate and less subjective method for counting parasites is desirable. In this study mitochondrial dye (Mitotracker Red CMXRos) was used for obtaining reliable live parasite counts through flow cytometry. METHODS: Both asynchronous and tightly synchronized asexual blood stage cultures of Plasmodium falciparum were stained with CMXRos and subjected to detection by flow cytometry and fluorescence microscopy. The parasite counts obtained by flow cytometry were compared to standard microscopic counts obtained through examination of Giemsa-stained thin smears. A comparison of the ability of CMXRos to stain live and compromised parasites (induced by either medium starvation or by anti-malarial drug treatment) was carried out. Finally, parasite counts obtained by CMXRos staining through flow cytometry were used to determine specific growth inhibition index (SGI) in an antibody-dependent cellular inhibition (ADCI) assay. RESULTS: Mitotracker Red CMXRos can reliably detect live intra-erythrocytic stages of P. falciparum. Comparison between staining of live with compromised parasites shows that CMXRos predominantly stains live parasites with functional mitochondria. Parasite counts obtained by CMXRos staining and flow cytometry were highly reproducible and can reliably determine the ability of IgG from hyper-immune individuals to inhibit parasite growth in presence of monocytes in ADCI assay. Further, a dose-dependent parasite growth inhibitory effect could be detected for both total IgG purified from hyper-immune sera and affinity purified IgGs against the N-terminal non-repeat region of GLURP in ADCI assays coupled with determination of parasite counts through CMXRos staining and flow cytometry. CONCLUSIONS: A flow cytometry method based on CMXRos staining for detection of live parasite populations has been optimized. This is a rapid and sensitive method with high inter-assay reproducibility which can reliably determine the anti-parasite effect mediated by antibodies in functional in vitro assays such as ADCI assay.

High levels of fetal DNA are associated with increased risk of spontaneous preterm delivery.

OBJECTIVE: To assess whether spontaneous preterm delivery can be predicted from the amount of cell free fetal DNA (cffDNA) as determined by routine fetal RHD genotyping at 25 weeks' gestation. STUDY DESIGN: Cohort study including RhD negative women participating in a routine RHD screening programme. A standard dilution curve was used to quantify the amounts of cffDNA. Values above the 95(th) centile for the study population defined high levels of cffDNA. RESULTS: We found a highly significant association between preterm delivery and cffDNA levels above the 95(th) centile (p = 0.002). Using logistic regression, women with high levels of cffDNA had an odds ratio of 6.3 (95% confidence interval: 1.9-20.9) for preterm delivery before 37 weeks and an odds ratio for delivery before 34 weeks of 16.6 (95% confidence interval: 3.2-84.7) when adjusting for gestational age at sampling, body mass index and previous miscarriages/terminations of pregnancy. CONCLUSION: High levels of cffDNA at 25 weeks are associated with increased risk of spontaneous preterm delivery.

Identification of MHC class II restricted T-cell-mediated reactivity against MHC class I binding Mycobacterium tuberculosis peptides.

Major histocompatibility complex (MHC) class I restricted cytotoxic T lymphocytes (CTL) are known to play an important role in the control of Mycobacterium tuberculosis infection so identification of CTL epitopes from M. tuberculosis is of importance for the development of effective peptide-based vaccines. In the present work, bioinformatics technology was employed to predict binding motifs of 9mer peptides derived from M. tuberculosis for the 12 HLA-I supertypes. Subsequently, the predicted peptides were synthesized and assayed for binding to HLA-I molecules in a biochemically based system. The antigenicity of a total of 157 peptides with measured affinity for HLA-I molecules of K(D) ≤ 500 nM were evaluated using peripheral blood T cells from strongly purified protein derivative reactive healthy donors. Of the 157 peptides, eight peptides (5%) were found to induce T-cell responses. As judged from blocking with HLA class I and II subtype antibodies in the ELISPOT assay culture, none of the eight antigenic peptides induced HLA class I restricted CD8(+) T-cell responses. Instead all responses were blocked by pan-HLA class II and anti-HLA-DR antibodies. In addition, CD4(+) T-cell depletion before the 10 days of expansion, resulted in total loss of reactivity in the ELISPOT culture for most peptide specificities. FACS analyses with intracellular interferon-γ staining of T cells expanded in the presence of M. tuberculosis peptides confirmed that the responsive cells were indeed CD4(+). In conclusion, T-cell immunity against HLA-I binding 9mer M. tuberculosis-derived peptides might in many cases turn out to be mediated by CD4(+) T cells and restricted by HLA-II molecules. The use of 9mer peptides recognized by both CD8(+) and CD4(+) T cells might be of importance for the development of future M. tuberculosis peptide-based vaccines.

Alterations in osteoclast function and phenotype induced by different inhibitors of bone resorption--implications for osteoclast quality.

BACKGROUND: Normal osteoclasts resorb bone by secretion of acid and proteases. Recent studies of patients with loss of function mutations affecting either of these processes have indicated a divergence in osteoclastic phenotypes. These difference in osteoclast phenotypes may directly or indirectly have secondary effects on bone remodeling, a process which is of importance for the pathogenesis of both osteoporosis and osteoarthritis. We treated human osteoclasts with different inhibitors and characterized their resulting function. METHODS: Human CD14 + monocytes were differentiated into mature osteoclasts using RANKL and M-CSF. The osteoclasts were cultured on bone in the presence or absence of various inhibitors: Inhibitors of acidification (bafilomycin A1, diphyllin, ethoxyzolamide), inhibitors of proteolysis (E64, GM6001), or a bisphosphonate (ibandronate). Osteoclast numbers and bone resorption were monitored by measurements of TRACP activity, the release of calcium, CTX-I and ICTP, as well as by counting resorption pits. RESULTS: All inhibitors of acidification were equally potent with respect to inhibition of both organic and inorganic resorption. In contrast, inhibition of proteolysis by E64 potently reduced organic resorption, but only modestly suppressed inorganic resorption. GM6001 alone did not greatly affect bone resorption. However, when GM6001 and E64 were combined, a complete abrogation of organic bone resorption was observed, without a great effect on inorganic resorption. Ibandronate abrogated both organic and inorganic resorption at all concentrations tested [0.3-100 microM], however, this treatment dramatically reduced TRACP activity. CONCLUSIONS: We present evidence highlighting important differences with respect to osteoclast function, when comparing the different types of osteoclast inhibitors. Each class of osteoclast inhibitors will lead to different alterations in osteoclast quality, which secondarily may lead to different bone qualities.

Screening of protein kinase inhibitors identifies PKC inhibitors as inhibitors of osteoclastic acid secretion and bone resorption.

BACKGROUND: Bone resorption is initiated by osteoclastic acidification of the resorption lacunae. This process is mediated by secretion of protons through the V-ATPase and chloride through the chloride antiporter ClC-7. To shed light on the intracellular signalling controlling extracellular acidification, we screened a protein kinase inhibitor library in human osteoclasts. METHODS: Human osteoclasts were generated from CD14+ monocytes. The effect of different kinase inhibitors on lysosomal acidification in human osteoclasts was investigated using acridine orange for different incubation times (45 minutes, 4 and 24 hours). The inhibitors were tested in an acid influx assay using microsomes isolated from human osteoclasts. Bone resorption by human osteoclasts on bone slices was measured by calcium release. Cell viability was measured using AlamarBlue. RESULTS: Of the 51 compounds investigated only few inhibitors were positive in both acidification and resorption assays. Rottlerin, GF109203X, Hypericin and Ro31-8220 inhibited acid influx in microsomes and bone resorption, while Sphingosine and Palmitoyl-DL-carnitine-Cl showed low levels of inhibition. Rottlerin inhibited lysosomal acidification in human osteoclasts potently. CONCLUSIONS: In conclusion, a group of inhibitors all indicated to inhibit PKC reduced acidification in human osteoclasts, and thereby bone resorption, indicating that acid secretion by osteoclasts may be specifically regulated by PKC in osteoclasts.

Characterization of acid flux in osteoclasts from patients harboring a G215R mutation in ClC-7.

The chloride-proton antiporter ClC-7 has been speculated to be involved in acidification of the lysosomes and the resorption lacunae in osteoclasts; however, neither direct measurements of chloride transport nor acidification have been performed. Human osteoclasts harboring a dominant negative mutation in ClC-7 (G215R) were isolated, and used these to investigate bone resorption measured by CTX-I, calcium release and pit scoring. The actin cytoskeleton of the osteoclasts was also investigated. ClC-7 enriched membranes from the osteoclasts were isolated, and used to test acidification rates in the presence of a V-ATPase and a chloride channel inhibitor, using a H(+) and Cl(-) driven approach. Finally, acidification rates in ClC-7 enriched membranes from ADOII osteoclasts and their corresponding controls were compared. Resorption by the G215R osteoclasts was reduced by 60% when measured by both CTX-I, calcium release, and pit area when comparing to age and sex matched controls. In addition, the ADOII osteoclasts showed no differences in actin ring formation. Finally, V-ATPase and chloride channel inhibitors completely abrogated the H(+) and Cl(-) driven acidification. Finally, the acid influx was reduced by maximally 50% in the ClC-7 deficient membrane fractions when comparing to controls. These data demonstrate that ClC-7 is essential for bone resorption, via its role in acidification of the lysosomes and resorption lacunae in osteoclasts.

GPDPLQ1237-A Type II Collagen Neo-Epitope Biomarker of Osteoclast- and Inflammation-Derived Cartilage Degradation in vitro.

C-telopeptide of type II collagen (CTX-II) has been shown to be a highly relevant biomarker of cartilage degradation in human rheumatic diseases, if measured in synovial fluid or urine. However, serum or plasma CTX-II have not been demonstrated to have any clinical utility to date. Here, we describe the GPDPLQ1237 ELISA which targets the EKGPDPLQ↓ neo-epitope, an elongated version of the CTX-II neo-epitope (EKGPDP↓), speculated to be a blood-precursor of CTX-II generated by the cysteine protease cathepsin K. Human osteoclast cartilage resorption cultures as well as oncostatin M and tumour necrosis factor α-stimulated bovine cartilage explant cultures were used to validate GPDPLQ1237 biologically by treating the cultures with the cysteine protease inhibitor E-64 and/or the matrix metalloproteinase (MMP) inhibitor GM6001 to assess the potential contributions of these two protease classes to GPDPLQ1237 release. Cartilage resorption-derived GPDPLQ1237 release was inhibited by E-64 (72.1% inhibition), GM6001 (75.5%), and E-64/GM6001 (91.5%), whereas CTX-II release was inhibited by GM6001 (87.0%) but not by E-64 (5.5%). Cartilage explant GPDPLQ1237 and CTX-II release were both fully inhibited by GM6001 but were not inhibited by E-64. No clinically relevant GPDPLQ1237 reactivity was identified in human serum, plasma, or urine from healthy donors or arthritis patients. In conclusion, the GPDPLQ1237 biomarker is released during osteoclast-derived cysteine protease- and MMP-mediated cartilage degradation in vitro, whereas CTX-II release is mediated by MMPs and not by cysteine proteases, as well as from MMP-mediated cartilage degradation under a pro-inflammatory stimulus. These findings suggest that GPDPLQ1237 may be relevant in diseases with pathological osteoclast activity and cartilage degradation. Further studies are required to validate the neo-epitope in human samples.

Osteoclasts secrete non-bone derived signals that induce bone formation.

Bone turnover is a highly regulated process, where bone resorption in the normal healthy individual always is followed by bone formation in a manner referred to as coupling. Patients with osteopetrosis caused by defective acidification of the resorption lacuna have severely decreased resorption, in face of normal or even increased bone formation. This suggests that osteoclasts, not their resorptive activity, are important for sustaining bone formation. To investigate whether osteoclasts mediate control of bone formation by production of bone anabolic signals, we collected conditioned media (CM) from human osteoclasts cultured on either bone or plastic, and tested their effects on bone nodule formation by osteoblasts. Both types of CM were shown to dose-dependently induce bone nodule formation, whereas non-conditioned osteoclast culture medium had no effects. These data show that osteoclasts secrete non-bone derived factors, which induce preosteoblasts to form bone-like nodules, potentially explaining the imbalanced coupling seen in osteopetrotic patients.

Identification of Rv0222 from RD4 as a novel serodiagnostic target for tuberculosis.

Forty-seven Mycobacterium tuberculosis genes from the 'regions of difference' RD2-7, RD9-13 and RD15 were cloned and expressed, and the purified recombinant proteins were screened for their serodiagnostic potential. Evaluation of six selected proteins in serum samples from Danish resident tuberculosis patients and healthy controls led to identification of Rv0222 as the most promising serodiagnostic antigen. Recognition of the Rv0222 was compared with the 38 kDa protein and a fusion protein of the RD1 proteins ESAT-6 and CFP10 in a serum panel from pulmonary tuberculosis (TB) patients from Uganda. The highest overall sensitivity was observed for Rv0222 compared to BCG-vaccinated non-endemic healthy controls as well as symptomatic endemic controls. Importantly, Rv0222 identified human immuno deficiency (HIV) virus-positive patients and HIV-negative patients with the same overall sensitivity. The results emphasize the importance of cut-off values in TB endemic regions based on endemic control individuals to diagnose active TB, and identify Rv0222 as a promising new antigen for serodiagnosis of TB in both HIV-negative and HIV-positive patients.

Recombinant human immunoglobulin (Ig)A1 and IgA2 anti-D used for detection of IgA deficiency and anti-IgA.

BACKGROUND: To avoid anaphylactic reactions, immunoglobulin (Ig)A-deficient patients with anti-IgA should be transfused with IgA-deficient blood components. There is a need for fast and robust assays for demonstration of IgA deficiency and for detection of anti-IgA. STUDY DESIGN AND METHODS: Recombinant human IgA1 and IgA2 anti-D molecules were constructed, expressed in Chinese hamster ovary cells, and purified. These antibodies were used to sensitize group O D+ red blood cells (RBCs) for use as indicator cells, either in the format of a passive hemagglutination inhibition assay for detection of IgA deficiency or in a passive hemagglutination assay for detection of anti-IgA. Both assays were performed in gel card. RESULTS: The sensitivity for IgA detection was adjusted to approximately 100 ng per mL. The assay for demonstration of IgA deficiency correlated with an enzyme-linked immunosorbent assay for quantification of IgA. Anti-IgA were easily detected, and the reactivity with IgA anti-D-sensitized RBCs could be inhibited by purified IgA1 and/or IgA2 and by normal plasma containing IgA but not by IgA-deficient plasma. Anti-IgA was found in 64 percent of IgA-deficient donors with less than 3 ng of IgA per mL. CONCLUSION: The assays for detection of IgA and anti-IgA described in this article are fast and robust. Furthermore, they are applicable in all standard blood typing laboratories and are therefore well suited for immediate investigation of transfusion reactions.

Bioactivity and stability of endogenous fibrogenic factors in platelet-rich fibrin.

Platelet-rich fibrin (PRF) is an autologous fibrin sealant (FS) enriched with a platelet concentrate (> 1,000,000 platelets/microL) produced by the automated Vivostat system and used to enhance wound healing. The effects of PRF were compared with supernatant from thrombin-activated platelet concentrate, recombinant human platelet-derived growth factor (rhPDGF) isoforms, and a homologous FS in cultured normal human dermal fibroblasts. Also, the release of selected endogenous growth factors from PRF and their stability against proteolytic degradation were studied. The proliferative effect of PRF exceeded that of FS and rhPDGF-BB, although it was lower than thrombin-activated platelet concentrate possibly due to sustained growth factor release from platelets in PRF. Anti-PDGF antibody blocked the mitogenic effect of rhPDGF-BB but not that of PRF in growth-arrested fibroblasts. PRF promoted secretion of carboxyterminal propeptide of type I collagen into conditioned medium while rhPDGF-AB had no significant effect on collagen biosynthesis. Limited proteolysis of PDGF-AB and no proteolysis of transforming growth factor-beta1 (TGF-beta1) in PRF were observed with trypsin treatment, whereas rhPDGF-AB and rhTGF-beta1 in bovine serum albumin, matching the total protein concentration of PRF, were almost completely degraded after 24 hours at 37 degrees C. To conclude, PRF provides sustained release and protection against proteolytic degradation of endogenous fibrogenic factors important for wound healing.