Kamal R, Natrajan M, Katoch K, Katoch V M
National JALMA Institute for Leprosy and Other Mycobacterial Diseases, Agra-282 001, India.
Indian J Lepr. 2010 Oct-Dec;82(4):195-200.
A large proportion of early cases of leprosy in children remain AFB negative in skin smears. Such cases required additional techniques to confirm the diagnosis. In situ PCR on slit- skin smears is minimally invasive and less cumbersome as compared to skin biopsies. This study was initiated in our institute with the objective to evaluate the diagnostic value of in situ PCR on slit- skin smears in pediatric leprosy. A total of 25 cases of leprosy below 16 years of age were included in the study. After detailed history and thorough clinical examination, informed consent was obtained from the parents of children for slit- skin smears from lesion sites for AFB staining and for in situ PCR technique. Cases were clinically categorized according to IAL classification into indeterminate (I), tuberculoid tuberculoid (TT), borderline tuberculoid (BT), borderline borderline (BB), borderline lepromatous (BL) and lepromatous (LL). Most of the patients (76%) were between 9-16 years of age and 64% of the cases had history of contact with leprosy patients within the family. Skin smears were positive for AFB in only 20% of the cases. On applying in situ PCR, it was observed that 62.5% cases of I/TT/BT/BB category and 88.8% of BL/LL category gave positive signals. Overall in situ PCR confirmed the diagnosis in 72% cases while by slit smears diagnosis was confirmed in only 20% of cases. Further, out of 20 skin smear negative cases, 13 were positive by in situ PCR. Specificity of the signals of in situ PCR was established by demonstrating the absence of signals in nonleprosy dermatological conditions of vitiligo and P.alba. This study supports the potential usefulness of in situ PCR on slit- skin smears of early pediatric leprosy cases. This strategy will be especially useful in cases where skin smears are negative and in those cases where skin biopsy can not be done either because of unusual locations of lesions or because of sensitive age of the patients.
儿童早期麻风病例中有很大一部分皮肤涂片抗酸杆菌（AFB）检测呈阴性。此类病例需要借助其他技术来确诊。与皮肤活检相比，对皮肤涂片进行原位聚合酶链反应（PCR）的侵入性最小且操作更简便。本研究在我们研究所开展，目的是评估对儿童麻风病患者的皮肤涂片进行原位PCR的诊断价值。该研究共纳入了25例16岁以下的麻风病患者。在详细询问病史并进行全面临床检查后，获得了患儿家长对从皮损部位采集皮肤涂片进行AFB染色及原位PCR技术检测的知情同意。根据国际麻风病防治协会（IAL）分类法，将病例临床分类为未定类（I）、结核样型（TT）、界线结核样型（BT）、中间界线类（BB）、界线类偏瘤型（BL）和瘤型（LL）。大多数患者（76%）年龄在9至16岁之间，64%的病例有家族内与麻风病患者接触史。仅20%的病例皮肤涂片AFB检测呈阳性。应用原位PCR后发现，I/TT/BT/BB类病例中有62.5%呈阳性信号，BL/LL类病例中有88.8%呈阳性信号。总体而言，原位PCR确诊了72%的病例，而通过皮肤涂片仅确诊了20%的病例。此外，在20例皮肤涂片阴性的病例中，有13例通过原位PCR呈阳性。通过在白癜风和白色糠疹等非麻风性皮肤病中未检测到信号，确定了原位PCR信号的特异性。本研究支持对儿童早期麻风病病例的皮肤涂片进行原位PCR具有潜在的实用价值。该策略在皮肤涂片阴性的病例以及因皮损位置特殊或患者年龄敏感而无法进行皮肤活检的病例中尤其有用。
