Inductively coupled plasma mass spectrometry assay for quantification of free infliximab in serum.

TNF antagonists such as infliximab are effective for the treatment of several inflammatory and autoimmune diseases. Recent clinical studies have advocated the importance of measuring trough infliximab levels to guide treatment decisions. We have developed a novel assay for measuring serum free infliximab levels using inductively coupled plasma-mass spectrometry (ICP-MS).

Simple dilute-and-shoot method for urinary vanillylmandelic acid and homovanillic acid by liquid chromatography tandem mass spectrometry.

Background: Neuroblastomas are pediatric tumors characterized by overproduction of catecholamines. The catecholamine metabolites, vanillylmandelic acid (VMA) and homovanillic acid (HVA), are used in clinical evaluation of neuroblastoma. Tandem mass spectrometry (LC-MS/MS) is an effective analytical method for measurement of VMA and HVA in urine.

Clinical laboratory application of a reporter-gene assay for measurement of functional activity and neutralizing antibody response to infliximab.

Background: TNF-α antagonists such as infliximab are effective for the treatment of inflammatory bowel disease and other inflammatory and autoimmune diseases. Development of an immune response and subsequent neutralizing antibodies against these protein-based drugs is a major impediment that contributes to therapeutic failure, or adverse effects such as hypersensitivity reactions. As opposed to empirical dose-escalation strategies, rational and cost-effective evaluation of clinical non-responsiveness includes measurement of serum drug levels, and detection of drug-specific antibodies.

Toxic and Essential Element Concentrations in Iberian Ibex (Capra pyrenaica) from the Sierra Nevada Natural Park (Spain): Reference Intervals in Whole Blood.

Iberian ibex (Capra pyrenaica) blood samples from the Sierra Nevada Natural Park (Spain) were analyzed to establish concentrations of toxic and essential elements. Samples (whole blood from 32 males and 34 females) were taken from wild animals and the concentrations of inorganic elements considered as (1) non-essential and toxic (Pb, Cd and As), (2) essential but potentially toxic (Cu, Zn and Mn) and (3) occasionally beneficial (B, Cr, Al and Ni), as well as (4) essential minerals (Ca, Na, K, P, Mg, S, Co and Fe), were analyzed. The low concentration of Pb and Cd indicated that there is no heavy metal contamination in this geographical area for these elements.

Identification and validation of shrimp-tropomyosin specific CD4 T cell epitopes.

Background: Shellfish allergy is an immune-mediated adverse reaction to allergenic shellfish and is responsible for significant morbidity and mortality. CD4 T cell responses play an important role in the pathophysiological mechanisms of sensitization and in production of IgE.

Objective: We sought to identify and validate CD4 T cell shrimp tropomyosin-derived epitopes and characterize CD4 T cell responses in subjects with a clinical history of shellfish allergy.

Resampling model of the complement component functional assay: Are we measuring what we think we are measuring?

Introduction: Complement component functional assay employs mix of the patient serum and serum depleted by the component of interest. To verify that such assay does actually measure functional activity of that component, authors introduced the simple resampling model of the functional test.

Methods: Virtual experiment of the functional test model consists of random sampling of component concentrations for depleted and patient sera.

Validation of cytomegalovirus immune competence assays for the characterization of CD8(+) T cell responses posttransplant.

Cytomegalovirus (CMV) infection is one of the most important infectious complications of transplantation. Monitoring CMV-specific CD8 T cell immunity is useful for predicting active CMV infection and for directing targeted antiviral therapy. In this study, we examined four basic parameters for validation of CMV-specific tetramer staining and peptide stimulation assays that cover five most frequent HLA class I alleles.

Reference interval computation: which method (not) to choose?

Background: When different methods are applied to reference interval (RI) calculation the results can sometimes be substantially different, especially for small reference groups. If there are no reliable RI data available, there is no way to confirm which method generates results closest to the true RI.

Methods: We randomly drawn samples obtained from a public database for 33 markers.

Penaeus monodon tropomyosin induces CD4 T-cell proliferation in shrimp-allergic patients.

Shellfish allergy affects approximately 2% of the population and can cause immediate hypersensitivity reactions such as urticaria, swelling, difficulty breathing, and, in some cases, anaphylaxis. Tropomyosin is the major shrimp allergen and binds IgE in two-thirds of patients. A total of 38 shrimp-allergic patients and 20 negative control subjects were recruited and evaluated on the basis of history, skin prick testing, specific immunoglobulin E (IgE) levels, and peripheral blood mononuclear cell proliferation in response to shrimp tropomyosin or shrimp tropomyosin-derived peptides.

Urine TGF- beta1 assay validation: spinning down urine samples could diminish TGF-beta1 signal.

Background: TGF-beta1 is a mediator of immune and anti-inflammatory responses. The present research was dedicated to the validation of the urine Quantikine Human TGF-beta1 ELISA assay.

Methods: A reference interval was developed utilizing 100 urine samples from healthy donors.

High soluble CD30, CD25, and IL-6 may identify patients with worse survival in CD30+ cutaneous lymphomas and early mycosis fungoides.

Histopathology alone cannot predict the outcome of patients with CD30+ primary cutaneous lymphoproliferative disorders (CD30CLPD) and early mycosis fungoides (MF). To test the hypothesis that serum cytokines/cytokine receptors provide prognostic information in these disorders, we measured soluble CD30 (sCD30), sCD25, and selected cytokines in cell cultures and sera of 116 patients with CD30CLPD and 96 patients with early MF followed up to 20 years. Significant positive correlation was found between sCD30 levels and sCD25, CD40L, IL-6, and IL-8, suggesting that CD30+ neoplastic cells secrete these cytokines, but not Th2 cytokines.

Specificity of EIA immunoassay for complement factor Bb testing.

Background: During the alternative complement pathway activation, factor B is cleaved in two fragments, Ba and Bb. Concentration of those fragments is about 2 logs lower than of factor B present in the blood, which makes fragment detection challenging because of potential cross-reactivity. Lack of information on Bb assay cross-reactivity stimulated the authors to investigate this issue.

Resampling approach for determination of the method for reference interval calculation in clinical laboratory practice.

Reference intervals (RI) play a key role in clinical interpretation of laboratory test results. Numerous articles are devoted to analyzing and discussing various methods of RI determination. The two most widely used approaches are the parametric method, which assumes data normality, and a nonparametric, rank-based procedure.

Post-transplant increased levels of serum sCD30 is a marker for prediction of kidney allograft loss in a 5-year prospective study.

Background: Levels of sCD30 represent a biomarker for early outcome in kidney transplantation. The purpose of this study was to determine the role of sCD30 levels for prediction of graft loss in the late post-transplant period.

Methods: Sera were collected immediately pre-transplant and yearly thereafter for up to 5-year post-transplant in 37 primary renal transplant recipients.

Binding of anti-HLA class I antibody to endothelial cells produce an inflammatory cytokine secretory pattern.

Current methods are inadequate for the diagnosis of early chronic allograft rejection. The goal of this study was to determine whether ligation of anti-HLA antibodies to endothelial cells is associated with a distinctive cytokine secretory pattern. Human iliac artery endothelial cells (HIAEC) cultured in vitro were incubated with w6/32, an anti-HLA class I mAb.