Development and Validation of an Enzyme Linked Immunosorbent Assay for Palivizumab Serum Determination

Palivizumab (Synagis®) is a humanized monoclonal antibody (IgG1K) composed of 95% human and 5% murine sequences. It is directed to an epitope in the A antigenic site of the F protein of respiratory syncytial virus (RSV). Palivizumab is used for prevention of serious lower respiratory tract disease caused by RSV in pediatric patients who are at increased risk of severe disease and is administered intramuscularly (IM) for a total of 5 monthly doses. Herein, we report on the development and validation of a very sensitive enzyme-linked immunosorbent assay (ELISA) to measure serum concentrations of palivizumab by a rabbit polyclonal antibody specifically produced against the murine sequence. The method was developed and validated according to the guidelines “Guidance for Industry” (1998) and has proved suitable for the determination of palivizumab serum levels in the target infant population. The ELISA assay was successfully applied to test the serum samples in an infant population who received palivizumab intramuscularly; thus, the assay could be used to determine serum levels in palivizumab-treated infants to optimize dosing and scheduling and to study the relationship between dose and clinical response.

Effects of Electromagnetic Stimulation on Osteogenic Differentiation of Human Mesenchymal Stromal Cells Seeded onto Gelatin Cryogel

Bone tissue engineering typically uses biomaterial scaffolds, osteoblasts or cells that can become osteoblasts, and biophysical stimulations to promote cell attachment and differentiation. In this study, we investigated the effects of an electromagnetic wave on mesenchymal stromal cells isolated from the bone marrow and seeded upon gelatin cryogel disks. In comparison with control conditions without electromagnetic stimulus, the electromagnetic treatment (magnetic field, 2 mT; frequency, 75 Hz) increased the cell proliferation and differentiation and enhanced the biomaterial surface coating with bone extracellular matrix proteins. Using this tissue-engineering approach, the gelatin biomaterial, coated with differentiated cells and their extracellular matrix proteins, may be used in clinical applications as an implant for bone defect repair.

A Prospective Study on Children with Initial Diagnosis of Transient Hypogammaglobulinemia of Infancy: Results from the Italian Primary Immunodeficiency Network

Transient hypogammaglobulinemia of infancy (THI) is a heterogenous disorder characterized by reduced serum IgG levels in early infancy. A putative diagnosis is initially made after exclusion of other causes of hypogammaglobulinemia while a definitive diagnosis of THI can only be made a posteriori in patients with normalization of IgG levels. The aim of this study is to characterize clinical and immunological features of children with an initial diagnosis of THI in correlation to natural outcome, and to assess predictive laboratory parameters of clinical evolution for this disorder. We prospectively analysed clinical and immunological characteristics of 77 THI children at initial diagnosis and of 57 patients at follow-up. Memory B cell subsets and in vitro immunoglobulin production were evaluated. Seventy patients (91%) showed clinical symptoms. Patients suffered from infections (91%), allergies (47%) and autoimmune disease (4%). During follow-up 41/57 children (72%) normalized IgG values, mostly within 24 months of age (p<0.001), allowing the diagnosis of THI. The 16 children who did not normalize their IgG levels showed a higher frequency of severe infections and autoimmune disease (p<0.01). Moreover, they expressed a reduced frequency of IgM and switched memory B cells (p<0.01) and an inability to produce IgG in vitro (p<0.02). We conclude that most patients with an initial diagnosis of THI spontaneously recover within 24 months of age and have a benign clinical course, while a subgroup of children with undefined hypogammaglobulinemia share a clinical and immunological profile with other primary immunodeficiencies. Early recognition of children with hypogammaglobulinemia during infancy who are likely to suffer from permanent immunodeficiencies later in life would allow prompt and appropriate laboratory and clinical interventions.

Restrictive cardiomyopathy in dermatomyositis

The association between dermatomyositis and restrictive cardiomyopathy has not been reported before. We present here the clinical, echocardiographic and muscle biopsy data for a patient with dermatomyositis and restrictive cardiomyopathy. In a 78-year-old male with a history of arterial hypertension, recurrent episodes of atrial fibrillation and syncopes, rupture of an infra-renal aortic aneurysm with complications (recurrent QT-prolongation, lumbo-sacral plexopathy, transient ischaemic attack, peripheral embolism), monoclonal gammopathy, subdural haematoma, focal seizures, megaloblastic anaemia, leucopenia, eosinophilia, elevated muscle enzymes and increasing tiredness, dermatomyositis was diagnosed upon clinical presentation, muscle enzyme and muscle biopsy findings. Cardiological examination revealed atrial fibrillation, left anterior hemiblock and restrictive cardiomyopathy. After the exclusion of various differentials for restrictive cardiomyopathy, a causative relationship between restrictive cardiomyopathy and dermatomyositis was assumed. This case suggests the need for suspecting restrictive cardiomyopathy in patients with dermatomyositis. Patients with dermatomyositis should undergo a comprehensive cardiological investigation as soon as the neurological diagnosis is established.