Comparison and Evaluation of Several Dermatophagoides Pteronyssinus Allergen Extracts for Skin Prick Test

Objective To evaluate the significance of several Dermatophagoides pteronyssinus allergen extracts for skin prick test(SPT) in patients allergic to Dermatophagoides pteronyssinus.Methods Two hundred and nineteen patients enrolled in Peking Union Medical College Hospital underwent SPT and serum specific IgE assay to detect the Dermatophagoides pteronyssinus allergen.Three kinds of house dust mite allergen extracts were used for SPT,including the Dermatophagoides pteronyssinus extract prepared by our laboratory(group A),standardized Dermatophagoides pteronyssinus extract(group B),and mixed extracts of Dermatophagoides pteronyssinus and Dermatophagoides farinae(group C).Human serum specific IgE result was regarded as the reference standard for diagnosis of Dermatophagoides pteronyssinus allergy.The receiver operating characteristic(ROC) curve was used to evaluate the diagnostic performance of SPT with the extracts of three groups.Results SPT results showed that the median wheal diameter of group A,group B,and group C was 0.43,0.35,and 0.28 cm,respectively,with significant difference among three groups(P<0.05).The difference was significant between group A and B(P<0.01) as well as group A and C(P<0.01),but not between group B and C(P>0.05).There was no local urticaria or systemic allergic reactions following the procedure of SPT.Local reaction was observed in 5 patients and delayed reaction was in 2 patients of group A.As for group B and C,local reaction occurred in 3 cases and delayed reaction in 2 cases in each group.The area under ROC curve of SPT with extract in group A,group B,and group C was 0.765,0.801,and 0.782,respectively.Based on the detection results of serum specific IgE,the sensitivity of SPT in diagnosis of Dermato-phagoides pteronyssinus allergy with extract of group A,group B,and group C was 92.4%,87.0%,and 81.5%,and the specificity was 60.6%,73.2%,and 74.8%,respectively.Conclusion The Dermatophagoides pteronyssinus extract for SPT prepared by our laboratory offers good sensitivity and specificity comparable to commercially available allergen extracts,and it may be an appropriate candidate for clinical screening and diagnosis of Dermatophagoides pteronyssinus allergy.

Leprosy without typical skin involvement but with concurrent tuberculosis: a case report

Leprosy is characterized by skin lesions and peripheral nerve damage. It may take a long time before the diagnosis can be confirmed if the patients have no typical skin involvements. Here we report an unusual case. A 40-year-old male with lepromatous leprosy showed a gradual onset of bilateral symmetrical neuropathies without characteristic skin manifestations seven years after onset and with pulmonary tuberculosis simultaneously. He was misdiagnosed as having Guillani-Barr6 syndrome and systemic necrotizing vasculitis for 10 years until the skin biopsy was performed. This case indicates that the risk of leprosy exists, though new cases being detected have significantly declined over the last 50 years; neurologists need to pay more attention to leprosy with various manifestations .