Jan Jaap van der Net

Publications (2)10.15 Total impact

• Source

  Available from: Patricia Vermeer

  Article: Safety and efficacy of meningococcal c vaccination in juvenile idiopathic arthritis.

  Evelien Zonneveld-Huijssoon, Arash Ronaghy, Marion A J Van Rossum, Ger T Rijkers, Fiona R M van der Klis, Elisabeth A M Sanders, Patricia E Vermeer-De Bondt, Arno W Hoes, Jan Jaap van der Net, Carla Engels, Wietse Kuis, Berent J Prakken, Maarten J D Van Tol, Nico M Wulffraat
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  ABSTRACT: To determine whether vaccinations aggravate the course of autoimmune diseases such as juvenile idiopathic arthritis (JIA) and whether the immune response to vaccinations may be hampered by immunosuppressive therapy for the underlying disease. In this multicenter cohort study, 234 patients with JIA (ages 1-19 years) were vaccinated with meningococcal serogroup C (MenC) conjugate to protect against serogroup C disease (caused by Neisseria meningitidis). Patients were followed up for disease activity for 1 year, from 6 months before until 6 months after vaccination. IgG antibody titers against MenC polysaccharide and the tetanus carrier protein were determined by enzyme-linked immunosorbent assay and toxin binding inhibition assay, respectively. A serum bactericidal assay was performed to determine the function of the anti-MenC antibodies. No change in values for any of the 6 components of the core set criteria for juvenile arthritis disease activity was seen after MenC vaccination. Moreover, no increase in the frequency of disease relapse was detected. Mean anti-MenC IgG concentrations in JIA patients rose significantly within 6-12 weeks after vaccination. Of 157 patients tested, 153 were able to mount anti-MenC IgG serum levels >2 micro g/ml, including patients receiving highly immunosuppressive medication. The 4 patients with a lower anti-MenC antibody response displayed sufficient bactericidal activity despite receiving highly immunosuppressive medication. The MenC conjugate vaccine does not aggravate JIA disease activity or increase relapse frequency and results in adequate antibody levels, even in patients receiving highly immunosuppressive medication. Therefore, patients with JIA can be vaccinated safely and effectively with the MenC conjugate.
  Arthritis & Rheumatism 02/2007; 56(2):639-46. · 7.87 Impact Factor
• Article: Osteogenesis imperfecta in childhood: impairment and disability. A prospective study with 4-year follow-up.

  Raoul H Engelbert, Cuno S Uiterwaal, Willem-Jan Gerver, Jan-Jaap van der Net, Hans E Pruijs, Paul J Helders
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  ABSTRACT: To study (1). changes in anthropometrics, joint range of motion (ROM), muscle strength, functional ability, caregiver assistance, and level of ambulation in children with osteogenesis imperfecta (OI) and (2). the prediction of clinical characteristics at the level of ambulation at follow-up and the prediction of clinical characteristics on progression or regression at the level of ambulation over time. Prospective study with follow-up of 4 years. A children's hospital that serves a nationwide center for treatment and research in children with OI in the Netherlands. At follow-up, 49 children (24 boys, 25 girls; mean age +/- standard deviation, 11.3+/-3.8y; range, 5.2-19.4y) participated. Not applicable. Anthropometry, joint ROM, muscle strength, fracture frequency, intramedullary rodding, level of ambulation, functional ability, and caregiver assistance. In type I OI, total joint ROM decreased significantly over time, especially in the lower extremities, with a significant decrease in generalized joint hypermobility according to Bulbena (median start, 7.5; interquartile range [IQR], 4-9; median end, 6; IQR, 2-7; P<.001). In types III and IV, a severe decrease in total joint ROM was present without significant changes over time. No significant changes in total muscle strength (upper or lower extremities) in the different types of OI were measured at follow-up. In OI type I, a significant increase in self-care (P=.003) and social function (P=.008) was measured; in type III, a significant increase in self-care (P=.003), mobility (P=.004), and social function (P=.005) was measured, with a significant decrease in parental assistance in self-care (P=.02) and mobility (P=.005). In type IV, a significant increase was observed in the self-care (P=.01) and social function domains (P=.02). Type of OI (regression coefficient=-1.0; 95% confidence interval [CI], -1.64 to -0.47) and total muscle strength were the only significant predictors for level of ambulation (regression coefficient=.01; 95% CI,.17-.32). Body weight was significantly lower in the group that progressed in level of ambulation (P=.03), whereas children with a decline in level of ambulation had significantly higher body weight (P=.05). Ours is the first study with a long-term follow-up that provides information concerning the natural course of developmental outcome parameters of OI in childhood. Joint ROM and muscle strength did not change significantly over time, possibly because of the biomechanical skeletal properties of the different OI types. Functional ability improved significantly over time, but, especially in types III and IV, did not reach normative values, possibly because of a plateau phase in functional ability. Knowledge of the natural course of the disease is essential to interpret the results from intervention studies.
  Archives of Physical Medicine and Rehabilitation 06/2004; 85(5):772-8. · 2.28 Impact Factor