Dinitrofluorobenzene skin test

Skin tests are the most commonly used in vivo test methods for measuring cellular immune function. Its essence belongs to delayed type hypersensitivity (type IV). When the body is infected by some bacteria (such as Mycobacterium tuberculosis, Brucella), viruses, or fungi, or contact with some small molecules, hapten substances, when combined with tissue proteins in the body to become a complete antigen. The body produces specific sensitized lymphocytes against these antigenic substances. When the corresponding antigen re-enters the body, the local lymphocytes release a variety of lymphokines. After 24 to 72 hours, the inflammation caused by mononuclear cell infiltration is manifested as redness and induration of the skin. This reaction is called delayed type metamorphosis. reaction. This reaction can be used as one of the indicators for judging the cellular immune function of the body. Basic Information Specialist classification: skin examination classification: immune examination Applicable gender: whether men and women apply fasting: not fasting Tips: Actively cooperate with the doctor during the examination. Normal value The degree of skin reaction was measured 48 to 72 hours after the challenge. Judging the results according to the following criteria 0 no response. + Partially reddish or scattered in red small papules less than half of the area. ++ redness is more than half of the area of ​​the ring, which is a positive reaction. +++ Red pimples almost cover the surface of the ring skin. ++++ has blisters or ulcers. 90% to 100% of normal people are positive for 100μg DNCB. Clinical significance The cellular immune function status is often parallel with the delayed hypersensitivity reaction. In patients with normal cellular immune function, more than 95% of delayed hypersensitivity reactions are positive; those with low cellular immune function have weak or no response. For example, 50% to 70% of patients with lepromatous tumors are negative, and malignant tumors develop rapidly or late, and the response often changes from positive to weakly positive or negative. Therefore, a delayed-type hypersensitivity skin test can be used to determine whether a patient has a cellular immune deficiency. It can be used for the observation of efficacy and prognosis of patients with leprosy and malignant tumors. Precautions Both DNCB and DNFB are small molecule chemicals with hapten properties, which are easy to bind to skin tissue proteins without significantly changing the internal structure of tissue proteins, and can cause delayed type hypersensitivity in most normal people. The cell immune function was detected by DNCB or DNFB skin test. It was more prevalent in early years. After the observation time of this test, it has a lifelong sensitization risk, and it can cause burns in young children, so it is less used. In recent years, this law has received attention and extensive research has been carried out. Newborns 2 to 3 weeks after birth can respond to DNCB or DNFB. Inspection process The test was carried out in two steps. First, the subject was sensitized, and 0.1 ml of acetone solution (containing DNFB 1 to 10 mg) was applied to the skin surface of the forearm flexor. After sensitization for 2 weeks, the acetone solution containing 50-100 μg of DNFB was applied to the ipsilateral skin, and the results were observed after 48 and 72 hours, respectively. A positive person develops contact dermatitis, which is characterized by redness, induration, blisters, and the like. Not suitable for the crowd There are no taboos. Adverse reactions and risks There are no related complications and hazards.

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