Diagnosis of gnathostomiasis by skin testing using partially purified specific antigen and total IgE levels.
BACKGROUND
A finding of antibodies to Gnathostoma spinigerum 24-kDa antigen by immunoblot analysis is currently used to confirm a diagnosis of gnathostomiasis. A simple skin test for the diagnosis of gnathostomiasis was developed, and the results were evaluated and compared with the standard Western blot (WB) test.


METHODS
This cross-sectional study was conducted at the Hospital for Tropical Diseases, Bangkok, Thailand, in 2008-2011. All eligible patients were tested with partially purified proteins of mAb-detected fractions pooled and sterilized by 0.2 μm diameter syringe filter, with a phenol saline solution of 1:10 w/v.


RESULTS
A total of 69 cases, 39 gnathostomiasis cases and 30 controls, were enrolled into the study; the median age (IQR) was 40 (30.5-52.5) years. The most common presenting symptom was edema (56/69, 81%). Gnathostomiasis cases having strong cutaneous reactions to the intradermal test (81%) were also positive by immunoblot. A significant correlation between skin and immunoblot tests was detected (p<0.001). The difference in total IgE levels between cases and controls was not statistically significant (p=0.51). Logistic regression models showed that positive WB and skin-test results were significantly associated with gnathostomiasis (p=0.001 and p=0.007, respectively).


CONCLUSIONS
Gnathostoma skin testing, using prepared fractionated antigen solution of Gnathostoma spinigerum, yields good reactivity and significantly correlates with the results of immunoblot testing.
Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, 420/6 Rajvithi Road, Ratchathewi, Bangkok 10400, Thailand.
Wirach
W
Maek-A-Nantawat
Valai
V
Bussaratid
Benjaluck
B
Phonrat
Wallop
W
Pakdee
Supaporn
S
Nuamtanong
Paron
P
Dekumyoy
D000328:Adult; D000918:Antibody Specificity; D000942:Antigens, Bacterial / Q000276:immunology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D058429:Gnathostomiasis / Q000175:diagnosis* / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000032:analysis*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D012882:Skin Tests / Q000379:methods*; D013785:Thailand
D000942:Antigens, Bacterial; D007073:Immunoglobulin E
Eosinophilia; Gnathostomiasis; IgE; Immunoblot; Skin test