79K / 206 New Skin Test DIASKINTEST (Recombinant Protein CFP10-ESAT6) for TB Infection

79K / 206 – New skin test DIASKINTEST® (recombinant protein CFP10-ESAT6) for TB infection diagnosis in children.

LVSlogotskaya1, VLitvinov1, P Seltsovsky1, AShuster2, VMartyanov2, ADemin2, YA Kochetkov1, AFilippov1, MMatveeva1.

1Scientific and Clinical Anti-tuberculosis Center Clinical Research – Moscow, Russia

2JSC "Masterklon" - Moscow (Russia)

The Russian company “Masterklon” has developed DIASKINTEST® (DST) for skin testing, which represents recombinant protein CFP10-ESAT6, produced by Echerichia coli BL21(DE3)/pCFP-ESAT.

We evaluated comparative positive reactions to DST and Mantoux in different groups of children and adolescents at high risk for TB and vaccinated with BCG (300 cases). The aim of the study was to evaluate identification of latent TB infection using DST.

The following groups of patients were studied: children and adolescents with pulmonary TB; children and adolescents with converted TB reactions; children and adolescents with hyperergic Mantoux; children and adolescents with increasing tuberculin sensitivity; children and adolescents with continuous positive tuberculin reactions; children and adolescents followed-up due to sputum negative TB contacts; children and adolescents vaccinated with BCG; children and adolescents with non-tuberculous diseases.

Results. DSTdemonstrated high sensitivity for both active TB and LTBI. A large proportion of patients treated for local TB, who did not complete chemotherapy, had positive DST reactions. Negative reactions were observed in patients with small TB processes. 78.3% of children, who completed treatment, had positive reactions. The highest sensitivity of DST was registered in children with converted tuberculin reactions and household sputum positive TB contacts – 91.7%. We could reliably suggest latent TB infection with active M. tuberculosis populations in these children. A high percentage of positive DST reactions were observed in children with hyperergic tuberculin reactions (76.2%). 33.3% of children followed-up due to sputum negative TB contacts had positive DST reactions. Only 3.0% of children and adolescents with continuous positive Mantoux reactions had positive DST reactions.

Such results confirm the ability of DST to serve as TB infection marker. In the early stage of infection the DST reaction is positive; however, 3 years later it becomes negative. DST does not induce delayed-type hypersensitivity in BCG-vaccinated patients. No positive reaction was observed in patients with non-specific diseases, which witnessed high specificity of the test – all the children had negative reactions. Non-specific allergy to DST was notobserved during the study. Children, which received preventive chemotherapy during 3 months, had fewer positive reactions to DST than those, which did not receive preventive chemotherapy.