Arora S K, Kumar B, Sehgal S
Departments of Immunopathology and *Dermatology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India.
Br J Dermatol. 2000 Jan;142(1):72-6. doi: 10.1046/j.1365-2133.2000.03244.x.
For a definitive diagnosis of cutaneous tuberculosis the demonstration of mycobacteria is essential, but this is generally not possible in skin lesions. Routinely available techniques have poor sensitivity and are time consuming, therefore, delaying the institution of timely therapy. The high sensitivity and speed of polymerase chain reaction (PCR) for the detection of infectious agents has prompted investigators to use this technique for the detection of Mycobacterium tuberculosis in body fluids such as cerebrospinal fluid or pleural fluid. In the present study, PCR was used to examine punch biopsy specimens from the affected skin of 10 patients with clinical diagnoses of tuberculosis verrucosa cutis, lupus vulgaris, scrofuloderma, papulonecrotic tuberculide and erythema induratum. A control group of 20 patients included individuals having skin manifestations with definite clinical diagnoses other than cutaneous tuberculosis, such as leprosy, fungal mycetoma, chronic bullous disease of childhood and pemphigus vulgaris. The PCR amplified products were dot hybridized with a probe which was random prime labelled with 32P. The results were compared with routine microbiological and histological findings. Among the test group, six of 10 (60%) were positive for M. tuberculosis by PCR, although their histopathology showed non-specific chronic inflammation with no definite diagnosis. Microbiological investigations, including acid-fast bacillus smear and culture, were positive in a single case of scrofuloderma. All patients in the control group were negative by PCR for M. tuberculosis. The data indicate that the combination of dot hybridization with PCR markedly increased the sensitivity and specificity of PCR. This may be a useful tool in the diagnosis of tuberculosis when conventional methods fail.
对于皮肤结核的确诊，分枝杆菌的鉴定至关重要，但在皮肤病变中通常无法做到这一点。常规可用技术敏感性差且耗时，因此会延误及时治疗的开展。聚合酶链反应（PCR）检测感染因子的高敏感性和速度促使研究人员将该技术用于检测脑脊液或胸腔积液等体液中的结核分枝杆菌。在本研究中，PCR用于检测10例临床诊断为疣状皮肤结核、寻常狼疮、瘰疬性皮肤结核、丘疹坏死性结核疹和硬结性红斑患者患部皮肤的钻孔活检标本。20例患者的对照组包括有明确临床诊断但非皮肤结核的皮肤表现患者，如麻风、真菌性足菌肿、儿童慢性大疱性疾病和寻常型天疱疮。PCR扩增产物与用32P随机引物标记的探针进行斑点杂交。将结果与常规微生物学和组织学检查结果进行比较。在试验组中，10例中有6例（60%）PCR检测结核分枝杆菌呈阳性，尽管其组织病理学显示为非特异性慢性炎症，无明确诊断。微生物学检查，包括抗酸杆菌涂片和培养，仅1例瘰疬性皮肤结核呈阳性。对照组所有患者PCR检测结核分枝杆菌均为阴性。数据表明，斑点杂交与PCR相结合显著提高了PCR的敏感性和特异性。当传统方法失败时，这可能是诊断结核病的有用工具。
