ABSTRACT
A 43-year-old man with a 19-year history of Crohn's disease experienced serum sickness with acute lobular panniculitis and vasculitis within 2 weeks of initiating 6-mercaptopurine therapy. He had no history of extraintestinal manifestations of Crohn's disease or drug allergy. Symptoms included disabling joint pain, proteinuria, fever, rash, and malaise. To our knowledge, this adverse drug reaction has not been described in association with 6-mercaptopurine.
Subject(s)
Crohn Disease/drug therapy , Immunosuppressive Agents/adverse effects , Mercaptopurine/adverse effects , Serum Sickness/chemically induced , Adult , Humans , Immunosuppressive Agents/therapeutic use , Male , Mercaptopurine/therapeutic useABSTRACT
The minute concentrations of many biochemically and clinically important substances are currently estimated by radioimmunoassay (RIA). Traditionally, the most popular approaches to the statistical analysis of RIA data have been to linearize the data through transformation and fit the calibration curve using least squares or to directly fit a nonlinear calibration curve using least squares. Estimates of the hormone concentration in patients are then obtained using this curve. Unfortunately, the transformation is frequently unsuccessful in linearizing the data. Furthermore, the least squares fit can lead to erroneous results in both approaches since the many sources of error which exist in the RIA process often result in outlier observations. In this paper, an approach to the analysis of RIA data which incorporates robust estimation methods is described. An algorithm is presented for obtaining the M-estimates of nonlinear calibration curves. The curves to be fitted are modified hyperbolae based on 12 to 16 observations. A procedure, based on the application of the Bonferroni Inequality, is presented for obtaining tolerance-like interval estimates of the concentration of the hormone of interest in the patients. Results of simulations are cited to support the method of construction of confidence bands for the fitted calibration curve. Data obtained from the Veteran's Hospital, Buffalo, New York are used to illustrate the application of the algorithm which is presented.
