Receiver operating characteristic curve analysis of four Aspergillus-specific IgG assays for the diagnosis of chronic pulmonary aspergillosis.

Measurement of Aspergillus-specific IgG is central to the diagnosis of chronic pulmonary aspergillosis (CPA), but manufacturers' guidance on test interpretation is based on unpublished data. We performed the first receiver operating characteristic (ROC) area under the curve (AUC) analysis to identify optimal cut-offs for this test in relation to European controls. Aspergillus-specific IgG levels were measured in sera from British adults with CPA and European healthy controls by ImmunoCAP, Immulite, Serion and Bio-Rad assays. ROC AUC analysis was performed to identify optimal cut-offs. ROC AUC results were; Bio-Rad 0.955, Immulite 0.948, ImmunoCAP 0.956 and Serion 0.944. Optimal diagnostic cut-offs were 1.5 AU/mL for Bio-Rad (93% sensitive, 98% specific), 25 mg/L for Immulite (93% sensitive, 99% specific), 50 mg/L for ImmunoCAP (84% sensitive, 96% specific) and 50 U/mL for Serion (84% sensitive, 91% specific). These cut-offs differ from manufacturers' guidance and from those previously calculated in relation to Ugandan controls.

Between-laboratory quality control of automated analysis of IgG antibodies against Aspergillus fumigatus.

Measurement of IgG antibodies against Aspergillus fumigatus is an important criterion for the diagnosis of aspergilloma, allergic bronchopulmonary aspergillosis, and extrinsic allergic alveolitis. In the present study, we compared IgG antibody analysis against A. fumigatus using 2 widely used automated immunochemistry systems. In a between-laboratory quality control program, good agreement was found between the results from laboratories that used the ImmunoCAP system; however, a laboratory that used the Immulite 2000 system found approx. 2-fold higher antibody levels in the quality control samples than did the ImmunoCAP system. Measurements of IgG against A. fumigatus in patient sera were significantly correlated (r(s) = 0.77, P < 0.0001). These results demonstrate that analysis of IgG antibodies against A. fumigatus with these 2 systems has reached a level of standardization that allows for direct comparison of quantitative results from different laboratories. For longitudinal analysis of IgG against A. fumigatus, reagents from the same manufacturer should be used.

Pharmacokinetics of intravenous immunoglobulin and outcome in Guillain-Barré syndrome.

OBJECTIVE: Intravenous immunoglobulin (IVIg) is the first choice treatment for Guillain-Barré syndrome (GBS). All patients initially receive the same arbitrary dose of 2g per kg body weight. Not all patients, however, show a good recovery after this standard dose. IVIg clearance may depend on disease severity and vary between individuals, implying that this dose is suboptimal for some patients. In this study, we determined whether the pharmacokinetics of IVIg is related to outcome in GBS. METHODS: We included 174 GBS patients who had previously participated in 2 randomized clinical trials. At entry, all patients were unable to walk unaided and received a standard dose of IVIg. Total IgG levels in serum samples obtained immediately before and 2 weeks after the start of IVIg administration were determined by turbidimetry and related to clinical outcome at 6 months. RESULTS: The increase in serum IgG (DeltaIgG) 2 weeks after IVIg treatment varied considerably between patients (mean, 7.8g/L; standard deviation, 5.6g/L). Patients with a low DeltaIgG recovered significantly more slowly, and fewer reached the ability to walk unaided at 6 months (log-rank p < 0.001). In multivariate analysis adjusted for other known prognostic factors, a low DeltaIgG was independently associated with poor outcome (p = 0.022). INTERPRETATION: After a standard dose of IVIg treatment, GBS patients show a large variation in pharmacokinetics, which is related to clinical outcome. This may indicate that patients with a small increase in serum IgG level may benefit from a higher dosage or second course of IVIg.

IgE-mediated hypersensitivity: patients with complex regional pain syndrome type 1 (CRPS1) vs the Dutch population. A retrospective study.

OBJECTIVE: To investigate whether hypersensitivity is more common in Complex Regional Pain Syndrome type 1 (CRPS1) patients than in the general population. In a recent study, the level of tryptase, a specific marker for mast cells, was significantly higher in blister fluid from the involved extremity of CRPS1 patients. This suggested that mast cells may play a role in the pathophysiology of CRPS1. Mast cells are major effectors in allergic reactions, and are also involved in a variety of noninfectious inflammatory diseases. Patients. Sixty-six Dutch patients with CRPS1 in one extremity were included. OUTCOME MEASURES: Allergy information was obtained from the medical history and a modified questionnaire based on the Europees Luchtweg Onderzoek Nederland 1 study. Total IgE and allergen-specific IgE were measured from blood samples. Also tryptase, as a marker for mast cells, was measured. The data from the questionnaire were compared with that of the general Dutch population, and the plasma levels were compared with reference values and data in the literature. RESULTS: The medical history did not differ from information provided in the questionnaire by the CRPS1 group. There was no significant difference between the answers to the questionnaire between the CRPS1 patients and the general population. The total IgE levels were elevated in 30% of the CRPS1 patients compared with 15-24% of the general population, and allergen-specific IgE and tryptase levels were comparable with the reference values. CONCLUSIONS: Based on the medical history, an allergy questionnaire, and objective laboratory findings we conclude that IgE-mediated hypersensitivity is not more common in CRPS1 patients than in the general population.

The role of topical negative pressure in wound repair: expression of biochemical markers in wound fluid during wound healing.

The clinical effects of topical negative pressure therapy (TNP) on wound healing are well described in numerous articles. While the mechanism(s) of action are not completely understood, it is postulated that reduction of local and interstitial tissue edema, increased perfusion of the (peri-) wound area, changed bacterial composition, and mechanical stimulation of the woundbed contribute to the clinical success. Our hypothesis is that with the removal of excessive fluid, proteolytic enzymes negatively influencing the healing process are removed. Our aim was to assess whether the concentrations of albumin, matrixmetalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinase (TIMP-1) were different between wounds treated with TNP and conventional gauze therapy. We analyzed wound fluid samples of 33 wounds treated with either TNP therapy (n=15) or conventional therapy (n=18) on albumin, pro- and activated MMP-9, TIMP-1, and the ratio of total MMP-9/TIMP-1. Albumin levels were found to increase significantly in acute wounds compared with chronic wounds; however, no difference could be found on comparing TNP with conventional therapy. We did find significantly lower levels of pro-MMP-9 and lower total MMP-9/TIMP-1 ratio in TNP-treated wounds during the follow-up of 10 days. These data strongly suggest that TNP therapy influences the microenvironment of the wound.

Plasma matrix metalloproteinase-9 levels and blood pressure in short children born small for gestational age and effects of growth hormone treatment.

CONTEXT: Short small-for-gestational-age (SGA) children have an increased systolic blood pressure (BP) that decreases during long-term GH treatment. The underlying mechanism is still unknown. Matrix metalloproteinases (MMPs) are zinc-dependent endoproteinases that are involved in the remodelling of the extracellular matrix (ECM) and are thought to play a role in atherosclerosis. High MMP-9 levels are found in hypertensive patients and predict cardiovascular mortality. OBJECTIVES: To investigate whether GH treatment affects plasma MMP-9 levels in short SGA children and whether these are related to BP. DESIGN: Case-control study. INTERVENTION: GH treatment vs. no treatment during 36 months. Patients Thirty-eight short SGA children receiving GH treatment vs. 17 sex- and age-matched untreated short SGA controls. OUTCOME MEASURE: Plasma MMP-9 levels and BP were measured at baseline, and after 6, 12 and 36 months of study. RESULTS: MMP-9 decreased significantly during 3 years of GH treatment but remained similar in untreated SGA controls. After 3 years of GH treatment, MMP-9 levels were significantly lower in the GH group than in the untreated SGA controls. Systolic BP SDS significantly decreased in the GH group but remained unaltered in the untreated SGA controls. MMP-9 levels did not correlate with systolic or diastolic BP. CONCLUSIONS: Plasma MMP-9 levels and systolic BP SDS decreased to almost 50% of baseline values in the GH group but remained unchanged in untreated SGA controls. Our data indicate that GH has a positive effect on both MMP-9 levels and systolic BP SDS.

Heterophilic antibody interference in a tryptase immunoassay.

OBJECTIVE: Investigation of the susceptibility of a tryptase immunoassay to interference by heterophilic antibodies. METHODS: The effect of preincubation with a blocking agent was investigated on the levels of tryptase, human anti-mouse antibodies and IgM rheumatoid factor in sera with elevated IgM rheumatoid factor levels. RESULTS: In 5 of 30 sera with IgM rheumatoid factor, tryptase levels were reduced at least twofold after pre-incubation with blocking reagent. A significant association was observed between the presence of IgM rheumatoid factor in the sera and the interference of tryptase immunoassay. There was no quantitative correlation found between the reduction in serum tryptase level by treatment with a blocking agent, and the amount of IgM rheumatoid factor was present. However, this reduction in serum tryptase was significantly correlated with the amount of human anti-mouse antibodies in the sera. After incubation with blocking agent, there was no change in IgM Rheumatoid factor level, but a significant decrease in human anti-mouse antibodies. CONCLUSION: The Phadia tryptase assay method, in its present form, is sensitive to interference by heterophilic antibodies.

Long-term GH treatment is not associated with disadvantageous changes of inflammatory markers and adipocytokines in children born small for gestational age.

CONTEXT: Low birth weight is associated with increased risks for adult cardiovascular disease (CVD) and diabetes mellitus type 2 (DM2). Adiponectin and resistin are hormones, considered, respectively, protective and disadvantageous regarding these risks. No data exist on the effect of long-term GH treatment on these hormones and inflammatory markers in children born small for gestational age (SGA). OBJECTIVE: To describe longitudinal changes in inflammatory markers and adipocytokines during and after a long-term dose-response GH study. DESIGN: Longitudinal dose-response study [group A: 1 mg/m(2) body surface area (BSA) (approximately 0.033 mg/kg/day) vs. group B: 2 mg/m(2) BSA (approximately 0.067 mg/kg/day)] and comparison with age-related controls. PATIENTS: One hundred and three SGA children. MEASUREMENTS: We measured adiponectin, resistin, interleukin-6 (IL-6) and C-reactive protein (CRP) levels at baseline, after 1 and 7 years of GH treatment and 6 months after discontinuation of GH. RESULTS: Adiponectin levels decreased over time, but remained comparable with controls. Resistin levels increased and remained lower or comparable with controls. There were no significant differences between the GH dosage groups. After the GH treatment was stopped, adiponectin was decreased in group B and resistin increased in group A. GH therapy did not affect IL-6 and CRP levels at any time point. An increase in body mass index (BMI) standard deviation score (SDS) over time was associated with a decrease in adiponectin levels. None of the markers were associated with insulin sensitivity. CONCLUSIONS: Long-term GH treatment is not associated with disadvantageous changes in adiponectin, resistin, IL-6 and CRP levels, neither during nor after GH treatment.

Tumor pyruvate kinase isoenzyme type M2 and immunochemical fecal occult blood test: performance in screening for colorectal cancer.

OBJECTIVES: Immunochemical fecal occult blood test (FOBT) and determination of tumor pyruvate kinase isoenzyme type M2 (TuM2-PK) in stool samples may be valuable new screening tools for colorectal cancer (CRC). The aim of this study was to compare the accuracy of fecal TuM2-PK testing with immunochemical FOBT in patients with CRC or adenomas. METHODS: A total of 52 patients with CRC were analyzed, 47 with colorectal adenomas, and 63 matched controls with a normal colonoscopy. Nineteen additional patients with inflammatory bowel disease were tested to determine influence of inflammation. Stool samples were analyzed with two immunochemical FOBTs, Immo-care and OC-Light, and with a commercial enzyme-linked immunosorbent assay for TuM2-PK. RESULTS: In patients with CRC, the sensitivity of TuM2-PK, Immo-care and OC-Light was respectively 85, 92 and 94%. In patients with adenomas, the sensitivity was respectively 28, 40 and 34%. Specificity for these tests was 90% for TuM2-PK and 97% for both immunochemical FOBTs. All tests showed a high positivity rate in patients with inflammatory bowel disease (79% for TuM2-PK and Immo-care, and 89% for OC-Light). CONCLUSION: Both immunochemical FOBTs appear valuable and are sensitive tests for CRC screening. TuM2-PK does not have supplemental value for screening for CRC because of a lower sensitivity and specificity. None of these tests is sensitive enough for detection of advanced adenomas. Patients with inflammatory bowel disease should be excluded from CRC screening when using immunochemical FOBT or TuM2-PK.

Effect of growth hormone therapy on serum adiponectin and resistin levels in short, small-for-gestational-age children and associations with cardiovascular risk parameters.

BACKGROUND: Adiponectin and resistin are fat cell-derived hormones, which are thought to be respectively protective and disadvantageous with regard to the development of cardiovascular disease and diabetes mellitus type 2. Low birth weight has been associated with increased risks for the development of these diseases. In short, small-for-gestational-age (SGA) children, GH therapy has several positive effects regarding cardiovascular risk factors. On the other hand, concern has been expressed about the effects of GH therapy on insulin sensitivity. METHODS: We measured adiponectin and resistin levels in 136 short prepubertal children born SGA and their association with cardiovascular risk parameters and growth factors. Also, we compared the levels with normal-statured controls. The effect of GH treatment was evaluated in 50 short SGA children vs. baseline and vs. an untreated sex- and age-matched SGA control group. RESULTS: Short SGA children had similar adiponectin and lower resistin levels, compared with normal-statured controls. In GH-treated SGA children, neither adiponectin nor resistin levels changed significantly during 2 yr of GH treatment. Compared with untreated sex- and age-matched SGA controls, GH-treated SGA children had similar adiponectin and lower resistin levels. Adiponectin correlated inversely with age but not any cardiovascular risk parameter or growth factor. Higher IGF-I levels in GH-treated children were associated with lower resistin levels. CONCLUSIONS: Compared with normal-statured controls, short prepubertal SGA children had similar adiponectin and lower resistin levels. Two years of GH treatment had no effect on their adiponectin and resistin levels.

Immunoblot and radioallergosorbent test inhibition studies of allergenic cross-reactivity of the predatory mite Amblyseius cucumeris with the house dust mite Dermatophagoides pteronyssinus.

BACKGROUND: In 1999, an extensive study among bell pepper growers showed that a predatory mite, Amblyseius cucumeris, is a potentially relevant source of occupational allergens because 23% of the population had positive skin prick test reactions. OBJECTIVE: To investigate whether cross-reactivity between A. cucumeris and Dermatophagoides pteronyssinus is responsible for the cosensitization to both mite species found in 58.7% of A. cucumeris-sensitized greenhouse workers. METHODS: Fifteen serum samples from greenhouse workers with work-related inhalant allergy and a positive radioallergosorbent test (RAST) reaction to A. cucumeris or D. pteronyssinus were selected for immunoblot analysis using extracts of both mites. A subselection (n = 5) was used for RAST and immunoblot inhibition to investigate potential cross-reactivity. RESULTS: On immunoblot, 2 distinct patterns were observed: one pattern showed common protein bands in A. cucumeris and D. pteronyssinus blots suggestive of cross-reactivity between A. cucumeris and D. pteronyssinus and the other pattern showed no shared protein bands. Dermatophagoides pteronyssinus RAST inhibition with A. cucumeris extract was low in 4 serum samples (<25% inhibition) and nearly absent in 1 serum sample; A. cucumeris RAST inhibition with D. pteronyssinus extract was high in 1 serum sample (75% inhibition), low in 2 serum samples (35% and <15% inhibition), and absent in 2 serum samples. These results were confirmed by immunoblot inhibition experiments. CONCLUSIONS: Amblyseius cucumeris, a new occupational allergen, has species-specific antigens and common antigens that are cross-reactive with the house dust mite D. pteronyssinus.