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Background & objectives: Leprosy type 1 reactions (T1R) are acute episodes of immune exacerbation that are a major cause of inflammation and nerve damage. T1R are diagnosed clinically and supported by histopathology. No laboratory marker is currently available that can accurately predict a T1R. Increased plasma and tissue expression of inducible nitric oxide synthase (i-NOS) and chemokine CXCL10 have been demonstrated in T1R. We studied the gene expression and immunoexpression of i-NOS, CXCL10 and its receptor CXCR3 in clinically and histopathologically confirmed patients with T1R and compared with non-reactional leprosy patients to understand which biomarker has better potential in distinguishing reaction from non-reaction. Methods: Gene expression of i-NOS, CXCL10 and CXCR3 was studied in 30 skin biopsies obtained from patients with borderline tuberculoid (BT), mid-borderline (BB) and borderline lepromatous (BL) leprosy with and without T1R by real-time PCR. Further validation was done by immunhistochemical expression on 60 borderline leprosy biopsies with and without T1R. Results: Of the 120 patients histopathological evaluation confirmed T1R in 65 (54.2%) patients. CXCR3 gene expression was significantly (P<0.05) higher in BT- and BB-T1R patients compared to those without T1R. The CXCL10 gene expression was significantly higher (P<0.05) in BB leprosy with T1R but the difference was not significant in patients with BT with or without T1R. Immunoexpression for CXCR3 was significant in both BB-T1R and BB (P<0.001) and BT and BT-T1R (P<0.001). Immunoexpression of CXL10 was significant only in differentiating BB from BB-T1R leprosy (P<0.01) and not the BT cases. i-NOS immunoexpression was not useful in differentiating reactional from non-reactional leprosy. Interpretation & conclusions: Both CXCL10 and CXCR3 appeared to be useful in differentiating T1R reaction in borderline leprosy while CXCR3 alone differentiated BT from BT-T1R. CXCR3 may be a potentially useful immunohistochemical marker to predict an impending T1R.
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Introduction Identifying risk factors for leprosy reactions can preempt clinicians to initiate prompt treatment to prevent associated morbidities. Thus, a retrospective study was done to elucidate the risk factors among 44 newly diagnosed leprosy patients in Sarawak General Hospital from 1993 to 2007. Materials and methods Case folders were searched for demographic data, clinical characteristics, slit skin smear results, and the presence of type 1 leprosy reactions, its treatment and outcome. Analysis was done to determine the relative risks for development of this reaction. Student t test was used for comparison of means. The level of significance was set at 0.05. Results Type 1 reaction was seen in 25% (n=11) of patients. It occurred in 44.4% (n=4) of borderline lepromatous (BL), 33.3% (n=1) of mid borderline (BB), 37.5% (n=3) of borderline tuberculoid (BT) and 30% (n=3) of tuberculoid (TT) patients. Borderline spectrum of disease gave a relative risk of 2 (95% CI 0.3-0.9) and age of 40 gave a relative risk of 1.8 (95% CI 0.3-0.9) for the development of type 1 reaction. Older mean age (mean 53.7 years cf. 37.0 years, p = 0.01) and earlier presentation to health care workers (mean 5.8 months cf. 11.9 months, p = 0.02) was also significant risk factors Extent of disease and gender were not identified as risk factors. Conclusion Risk factors for type 1 leprosy reaction were borderline leprosy, older patients and shorter duration of illness on presentation.