Negative Challenge Test Research Articles

Effect of Influenza Vaccine on Bronchoprovocation Testing in Normal Subjects

A study of 55 nonasthmatic patients was undertaken to determine if recent influenza vaccination is a justifiable exclusionary criteria for bronchoprovocation testing. Healthy subjects without history of asthma and with negative methacholine challenge tests were given an intramuscular injection of killed influenza vaccine. Methacholine challenge testing was repeated 24 h later. While a statistically significant decline in FEV1 at 188 methacholine dose units was demonstrated (p < 0.018), this was not clinically significant; none of the 55 subjects converted a negative test to positive. We conclude that recent influenza vaccination is not a sufficient exclusionary criterion for methacholine challenge testing. Positive results in a patient recently vaccinated would still indicate asthma in the correct clinical setting.

Capsaicin cough sensitivity decreases with successful treatment of chronic cough.

To assess the role of enhanced cough sensitivity in the pathogenesis of cough, we measured cough severity on a visual analogue scale (VAS) and capsaicin cough sensitivity (the concentration required to elicit two [C2] and five [C5] coughs) in 87 consecutive patients referred with chronic cough. Measurements were repeated after complete investigation and treatment, when patients were entered into one of four study groups: (1) treatment success (primary cause of cough successfully treated with elimination of the cough, n = 48); (2) primary treatment failure (treatment of potential primary cause of cough unsuccessful, n = 12); (3) cough treatment failure subgroup A (potential primary cause of cough identified and successfully treated but no improvement in cough, n = 8); and (4) cough treatment failure subgroup B (no potential primary cause of cough identified, n = 19). All patients in groups 3 and 4 were nonsmokers, had normal chest radiography and negative histamine challenge test, and failed to respond to intensive empirical treatment for rhinitis and gastroesophageal reflux. The VAS cough severity was lower and log C2 and C5 higher after treatment compared with initial values in the treatment success group but not in the other three groups. Enhanced sensitivity of airway nerves that mediate cough is important in the pathogenesis of nonproductive cough, and successful treatment is associated with a reduction in cough sensitivity. While enhanced sensitivity of airway nerves is usually present in patients with identifiable causes of chronic nonproductive cough, it is also found in other patients in whom the cause of cough is unknown.

Occupational asthma due to maleic anhydride.

Few reported cases of asthma due to maleic anhydride have been reported,12 although there have been several cases due to other acid anhydrides. Our case is unique in that the patient was exposed to both maleic anhydride (MA) and phthalic anhydride (PA). He had a negative challenge test to PA but reacted positively to MA showing the absence of cross reactivity between the two anhydrides in his case.

Immediate hypersensitivity to ovalbumin in children with hen's egg white allergy

Serum concentrations of IgE, IgG1 and IgG4 antibodies to ovalbumin and basophil sensitivity to ovalbumin were compared with the results of a titrated oral provocation test with ovalbumin in 27 children sensitive to hen's egg white, of whom 17 responded with an immediate hypersensitivity reaction. Neither the serum level of IgE, IgG1 and IgG4 antibodies to ovalbumin nor a positive histamine release test predicted the clinical relevance of ovalbumin sensitivity. The children with a positive challenge test had a significantly higher IgE/IgE4 ratio and tended to be younger and to have higher serum IgE levels and a higher IgG1/IgG4 ratio than those with a negative challenge test. We conclude that an oral provocation test is necessary to confirm the diagnosis of food allergy.

The value of the DNCB test in bladder cancer. Pretreatment evaluation of immune function and 5-year follow-up of patients with urinary bladder cancer.

In 68 patients with histologically verified tumors of the urinary bladder, cell-mediated and humoral immune parameters were investigated before therapy and the results were re-evaluated after a 5-year observation period in order to correlate them with relapse rate and survival time. Skin test reactivity, as measured with recall antigens (tuberculin, streptokinase-streptodornase, mumps, toxoplasmin and candidin), and serum levels of immunoglobulins do not differentiate between levels of invasion and grade of malignancy. However, it was found that patients with tumors of high grades of invasiveness and malignancy were anergic to the primary skin test antigen dinitrochlorobenzene (DNCB). Furthermore, a correlation between anergic reactivity to the DNCB test and absence of local inflammatory reactions at the tumor site was detected, showing that patients with a negative DNCB challenge test were those in whom no immunocytes could be detected in the intra- and peritumoral area. Survival time and incidence of relapse were also correlated with initial skin test reactivity to DNCB, i.e. all patients with tumor stage pT3 and skin test anergy developed recurrences and died within the 5-year observation period. The correlation between morphological inflammatory criteria and immunological parameters detected in patients with advanced tumor stages should therefore be taken into consideration when taking therapeutic decisions at the time of diagnosis.

New in vitro method for detecting asthma allergen

Changes in the morphology and number of basophils were examined after the addition in vitro of house dust extract in cells from seventy-seven patients with bronchial asthma. Morphological changes (reactive basophils) showed a close relation to the end-point titrations of antigen in skin tests, RAST score and bronchial provocation tests, but changes in number of basophils did not. With a RAST score of 2 or greater the change in reactive basophils varied from 40 to 80% (mean 58.1%), which was much greater than seen in persons with no RAST, score 0. Patients with positive bronchial inhalation tests, showed 40 to 80% (mean 57.8%) reactive basophils, whereas persons with a negative bronchial challenge test showed a range of reactive basophils from 0 to 50% (mean 28.9%). The difference in percentage of reactive basophils between the positive and negative groups of persons tested by bronchial inhalation was statistically significant.

False negative oxytocin challenge test: Report of three cases

False negative oxytocin challenge test: Report of three cases

False negative oxytocin challenge test associated with abdominal pregnancy

False negative oxytocin challenge test associated with abdominal pregnancy

Clinical and neurobehavioral effects of repeated intrauterine exposure to oxytocin: A prospective study

A prospective investigation of 114 pregnant women compared 54 with consistently negative oxytocin challenge tests to 60 women who did not have oxytocin challenge tests but did have fetal monitoring during labor. Despite more high-risk factors in the OCT group, there were no significant differences noted in the offspring. Specifically, extensive behavioral testing during the first 12 hours of life and at 3 days of age did not show any abnormalities. Furthermore, jaundice and respiratory distress were not seen more often after oxytocin exposure. These data argue that the OCT itself is without demonstrable adverse effects on the otherwise healthy fetus.

Relationship between the results of bronchial, nasal and conjunctival provocation tests in patients with asthma.

Skin tests and bronchial, nasal and conjunctival provocation tests with pollen and animal dander allergens were performed in thirty patients with atopic asthma. In vivo test results were compared only when the same batch of allergen had been used. A nasal reaction was mostly elicied at a lower concentration of allergen than was needed to elicit a bronchial reaction (P less than 0.01). Positive nasal reactions were often obtained when the corresponding bronchial tests were negative. The conjunctiva reacted to lower concentrations than the bronchi in a third of the instances of testing, with most of these being tests with mugwort allergen (P less than 0.05). A positive skin test in cases with a negative bronchial challenge test was often accompained by a positive nasal test and in some cases by a positive conjunctival test. It is concluded that nasal or conjunctival provocation tests do not replace bronchial challenge tests. In an asthmatic patient who gives no reaction to bronchial challenge with a particular allergen, a positive skin test may reflect a nasal allergy.

The Oxytocin Challenge Test

In a group of 152 high-risk pregnancies, 266 oxytocin challenge tests were reviewed. There were 137 patients with persistently negative oxytocin challenge tests with only one false-negative test being recorded. Fifteen patients who displayed a positive test at some time in their antepartum course are discussed along with other aspects of the oxytocin challenge test.