Unexpected interference of baby wash products with a cannabinoid (THC) immunoassay

ObjectivesThe results of newborn drug screening have far-reaching impact not only in healthcare, but also in the legal domain. Therefore, the accuracy of these results cannot be undervalued. When false positive cannabinoid (THC) screening results for this population were suspected at our institution, a multidisciplinary approach was initiated to evaluate the screening process for any pre-analytical or analytical sources of error or interference.Design and methodsMixtures of drug-free urine with various commercial products and materials that commonly contact newborns in our nursery were prepared and tested using the immunoassay screening methods in our laboratory. Additional commercial products were similarly tested; and when available, individual surfactants common to the interfering products were also evaluated.ResultsAddition of Head-to-Toe Baby Wash to drug-free urine produced a dose dependent measureable response in the THC immunoassay. Addition of other commercially available baby soaps gave similar results, and subsequent testing identified specific chemical surfactants that reacted with the THC immunoassay.ConclusionWe have identified commonly used soap and wash products used for newborn and infant care as potential causes of false positive THC screening results. Such results in this population can lead to involvement by social services or false child abuse allegations. Given these consequences, it is important for laboratories and providers to be aware of this potential source for false positive screening results and to consider confirmation before initiating interventions. Most importantly, we demonstrate the need for active involvement in the “total testing process,” as sources of error are not confined to the laboratory walls.     

Necrotizing streptococcal myositis of an extremity: a rare case report

Necrotizing myositis is a severe and very rare streptococcal soft tissue infection involving the superficial fascia and muscle. Its clinical symptoms are nonspecific until the appearance of a fulminant clinical course with soft tissue destruction and septic shock. A high mortality and morbidity rate has been reported in the few cases over the last century. Despite several attempts to better define the different entities causing this necrotizing soft tissue infection, no clear treatment has been outlined. We present the case of a 47-year-old woman who had an acute necrotizing myositis after a stab wound. The diagnosis of necrotizing myositis was only established after surgical treatment with a pathology report. We reviewed the literature to highlight the clinical difficulty of a preoperative diagnosis and surgical treatment.     

Instability and impending instability of the thoracolumbar spine in patients with spinal metastases: a systematic review

Metastatic disease commonly occurs in the spine and incidence is likely to increase secondary to improved survival rates in many cancer patients. Despite published research on instability in patients with metastatic disease of the thoracolumbar spine, controversy exists regarding risk factors for instability and indications for surgical stabilization. The objective of this systematic review was to determine what defines instability and impending instability in patients with metastatic disease of the thoracic and lumbar spine. We systematically reviewed the medical literature in order to identify all the relevant studies concerning patients with metastatic involvement of T1-L5, in the domains of biomechanics, epidemiology, clinical issues, and radiographic parameters. Two independent observers performed study selection, methodological quality assessment, and data extraction in a blinded and objective manner for all the identified studies. We were then able to define the criteria to identify instability of the spine with metastases. A literature search and review identified 14 relevant, good quality studies for inclusion. The predictors of instability included increased tumor size, a larger cross-sectional area of bone defect, increased force of spinal loading, decreased bone density, posterior location of the tumor within the vertebrae, destruction of the costovertebral joint, pedicle destruction in the thoracolumbar spine, increased axial rigidity, and sagittal spinal deformity. Definitive conclusions cannot be reached due to lack of evidence. However, variables such as tumor size, magnitude of spinal loading, bone density, tumor location within the vertebrae and spine, and tumor type are risk factors for instability in spinal metastases. Improved clinical research methodology for this patient population is required.     

Tumour antigen targeted monoclonal antibodies incorporating a novel multimerisation domain significantly enhance antibody dependent cellular cytotoxicity against colon cancer

Tumour antigen targeted antibodies (mAbs) can induce natural killer (NK) cells to kill tumours through antibody dependent cellular cytotoxicity (ADCC) upon engagement of NK cell expressed FcγRIIIa. FcγRIIIa polymorphisms partially dictate the potency of the ADCC response. The high affinity FcγRIIIa-158-valine (V) polymorphism is associated with more potent ADCC response than the low affinity FcγRIIIa-158-phenylalanine (F) polymorphism. Because approximately 45% of patients are homozygous for the FcγRIIIa-158-F polymorphism (FF genotype), their ability to mount ADCC is impaired. We investigated whether a novel mAb capable of binding multiple antigen specific targets and engaging multiple low affinity FcγRIIIa receptors could further enhance ADCC against colon cancer in vitro. Specifically, we generated a novel anti-epidermal growth factor receptor (EGFR) antibody (termed a stradobody?) consisting of an unmodified Fab sequence and two Immunoglobulin G, subclass 1 (IgG1) Fc domains separated by an isoleucine zipper domain and the 12 amino-acid IgG2 hinge. The stradobody? framework induced multimerisation and was associated with increased binding to the EGFR and FcγRIIIa. From a functional perspective, when compared to an unmodified anti-EGFR mAb with a sequence identical to cetuximab (a commercially available anti-EGFR mAb), stradobodies? significantly enhanced ADCC. These effects were observed using both KRAS wild type HT29 and KRAS mutant SW480 colon cancer cells as targets, and by NK cells obtained from healthy donors and a cohort of patients with colon cancer. These data suggest that high avidity cross-linking of multiple tumour surface antigens and multiple NK cell associated FcγRIIIa molecules can enhance ADCC and partially overcome impaired ADCC by FF genotype individuals in vitro.