Serological tests for visceral leishmaniasis.
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Biomedical subjects
Publications and source records attributed to Diana N J Lockwood.
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OBJECTIVES: To implement a policy of systematic screening for viral haemorrhagic fever (VHF) among travellers returning from African countries with fever, commencing at initial clinical contact. METHODS: A protocol based on UK Advisory Committee on Dangerous Pathogens guidance was developed collaboratively by medical, nursing and laboratory staff. Audit was carried out to quantify resource demands and effects on time to diagnose malaria, the main differential diagnosis. RESULTS: A protocol is now implemented for all patients presenting to HTD with fever, with clear guidelines for interaction with clinical and laboratory staff at each stage. The protocol required moderate amounts of clinical and laboratory staff time and resulted in some additional hospital admissions. The time to a diagnosis of malaria increased from a median of 90 (range 50-125) min in patients without VHF risk to a median of 140 (range 101-225) min (p=0.0025) in those assessed as at risk. CONCLUSIONS: Although all acute medical services need to have robust procedures for early detection of patients with serious transmissible conditions, few implement such a policy. Our protocol requires increased human and other resources but has no important impact on the rapidity of diagnosis of malaria, and is now embedded in local practice.
Early in the HIV epidemic it was feared that the disease would undermine leprosy control, as has occurred with tuberculosis. It was predicted that patients with leprosy and HIV coinfection would have an increased risk of lepromatous disease and a faster clinical evolution, and that the leprosy would be more difficult to treat. None of these concerns have materialised and the interaction between HIV and Mycobacterium leprae seems to be far more subtle than that between HIV and tuberculosis. We review the epidemiological, clinical, and pathological data relating to leprosy/HIV coinfection. The published epidemiological data are limited in quality but show neither an increased HIV prevalence among leprosy cases nor an alteration in clinical spectrum of leprosy among coinfected patients. Some data suggest that immune-mediated reactions that complicate leprosy occur at a higher frequency in coinfected patients. Leprosy has now been reported presenting as immune reconstitution disease among patients commencing highly active antiretroviral treatment. Histopathological observations reveal a normal spectrum of appearances in biopsies of leprosy lesions from coinfected patients, even among those with advanced immunodeficiency. These observations suggest that cell-mediated immune responses to M leprae are preserved at the site of disease despite evidence that these responses are abrogated systemically, by contrast with tuberculosis, in which the host granulomatous response is impaired by HIV coinfection. We speculate that this paradox may relate to differences between the activation state and rates of cell turnover within leprosy and tuberculosis granulomas that differentially affect the susceptibility of the granulomas to HIV. The interactions between leprosy and HIV have been little studied and further research on the clinical, pathological, and management aspects of this coinfection is warranted.
A 20-year (1985-2004) retrospective review of 39 patients with imported visceral leishmaniasis found that tourism to Mediterranean countries and HIV infection were associated with visceral leishmaniasis. Diagnosis was often delayed. Treatment with liposomal amphotericin B has improved prognosis. Visceral leishmaniasis should be made a reportable disease.
Erythema nodosum leprosum (ENL) or type 2 lepra reactions complicate lepromatous leprosy and borderline lepromatous leprosy. We report an 11-year retrospective case record analysis of 481 outpatients with borderline lepromatous and lepromatous leprosy at the Dhoolpet Leprosy Research Center in Hyderabad, India.. The overall prevalence of ENL was 24%, 49.4% among cases of lepromatous leprosy (LL) and 9% among cases of borderline lepromatous (BL) leprosy. Logistic regression analysis identified LL (odds ratio [OR] = 8.4, 95% confidence interval [CI] = 4.6-15.4, P < 0.001) and BL with a bacterial index > or = 4+ (OR = 5.2, 95% CI = 2.1-12.9, P = 0.001) as major risk factors. The average patient with ENL was male, 34.7 years of age, and had multiple episodes of ENL (mean = 3.1) over an 18.5-month period. Three types of ENL were identified: single acute ENL, multiple acute ENL (repeated discrete episodes), and chronic ENL (continuous episodes). Acute single ENL is rare, accounting for only 8% of cases. Chronic ENL accounted for 62.5% of the cohort. Chronic ENL was of longer duration and more severe. An age > or = 35 years was a risk factor for developing chronic ENL. Patients with chronic ENL were more compliant with multi-drug therapy, especially during the first six doses of multi-drug therapy. Distinguishing these different types of ENL would be useful for patient management and developing improved treatment of these debilitating reactions. Improved strategies for treatment and management of these reactions need to be developed.
Can leprosy be eliminated? This paper considers the question against the background of the WHO programme to eliminate leprosy. In 1991 the World Health Assembly set a target of eliminating leprosy as a public health problem by 2000. Elimination was defined as reaching a prevalence of < 1 case per 10 000 people. The elimination programme has been successful in delivering highly effective antibiotic therapy worldwide. However, despite this advance, new-case detection rates remain stable in countries with the highest rates of endemic leprosy, such as Brazil and India. This suggests that infection has not been adequately controlled by antibiotics alone. Leprosy is perhaps more appropriately classed as a chronic stable disease than as an acute infectious disease responsive to elimination strategies. In many countries activities to control and treat leprosy are being integrated into the general health-care system. This reduces the stigma associated with leprosy. However, leprosy causes long-term immunological complications, disability and deformity. The health-care activities of treating and preventing disabilities need to be provided in an integrated setting. Detecting new cases and monitoring disability caused by leprosy will be a challenge. One solution is to implement long-term surveillance in selected countries with the highest rates of endemic disease so that an accurate estimate of the burden of leprosy can be determined. It is also critical that broad-based research into this challenging disease continues until the problems are truly solved.
Type 1 (reversal or upgrading) reactions occur during or after chemotherapy in around 10% leprosy patients [Int J Lepr Other Mycobact Dis 61 (1993) 8-15]. The cause of this immunological upgrading is incompletely defined, although the approximately 2-fold increased risk of reaction in patients vaccinated with Mycobacterium w suggests that infection by mycobacteria other than Mycobacterium leprae may trigger this phenomenon [Vaccine 13 (1995) 1102-1110]. We report a case of borderline lepromatous leprosy in which we studied the antigenic specificity of peripheral blood mononuclear cells immediately before, and then during, a Type 1 reaction which provides more direct evidence in favor of this hypothesis.
Leprosy type 1 reactions (T1R) are due to increased cell-mediated immunity and result in localized tissue damage. The anti-inflammatory drug prednisolone is used for treatment, but there is little good in vivo data on the molecular actions of prednisolone. We investigated the effect of prednisolone treatment on tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-10, and transforming growth factor beta1 (TGF-beta1) mRNA and protein expression in blood and skin biopsies from 30 patients with T1R in India. After 1 month of prednisolone treatment the sizes of the skin granulomas were reduced, as were the grades of cells positive for TNF-alpha and IL-10 in skin lesions. Increased production of TGF-beta1 was seen in skin lesions after 6 months of prednisolone treatment. Expression of mRNA for TNF-alpha, IL-1beta, and TGF-beta1 was reduced, whereas no change in IL-10 mRNA expression was detected during treatment. The circulating cytokine profiles were similar in patients with and without T1R, and prednisolone treatment had no detectable effects on cytokine expression in the blood. The data emphasize the compartmentalization of pathology in T1R and the importance of the immune response in the skin. Clinical improvement and cytokine expression were compared. Surprisingly, patients with improved skin and nerve function and patients with nonimproved skin and nerve function had similar cytokine profiles, suggesting that clinical improvement is not directly mediated by the cytokines studied here. This in vivo well-controlled study of the immunosuppressive effects of prednisolone showed that the drug does not switch off cytokine responses effectively.
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The aim of this study was to find predictors of neuropathy and reactions, determine the most sensitive methods for detecting peripheral neuropathy, study the pathogenesis of neuropathy and reactions and create a bank of specimen, backed up by detailed clinical documentation. A multi-centre cohort study of 303 multibacillary leprosy patients in Northern India was followed for 2 years. All newly registered MB patients requiring a full course of MDT, who were smear positive and/or had six or more skin lesions and/or had two or more nerve trunks involved, were eligible. A detailed history was taken and physical and neurological examinations were performed. Nerve function was assessed at each visit with nerve conduction testing, warm and cold detection thresholds, vibrometry, dynamometry, monofilaments and voluntary muscle testing. Because the latter two are widely used in leprosy clinics, they were used as 'gold standard' for sensory and motor impairment. Other outcome events were type 1 and 2 reactions and neuritis. All subjects had a skin biopsy at registration, repeated at the time of an outcome event, along with a nerve biopsy. These were examined using a variety of immunohistological techniques. Blood sampling for serological testing was done at every 4-weekly clinic visit. At diagnosis, 115 patients had an outcome event of recent onset. Many people had skin lesions overlying a major nerve trunk, which were shown to be significantly associated with an increased of sensory or motor impairment. The most important adjusted odds ratios for motor impairment were, facial 4.5 (1.3-16) and ulnar 3.5 (1.0-8.5); for sensory impairment they were, ulnar 2.9 (1.3-6.5), median 3.6 (1.1-12) and posterior tibial 4.0 (1.8-8.7). Nerve enlargement was found in 94% of patients, while only 24% and 3% had paraesthesia and nerve tenderness on palpation, respectively. These increased the risk of reactions only marginally. Seven subjects had abnormal tendon reflexes and seven abnormal joint position sense. In all but one case, these impairments were accompanied by abnormalities in two or more other nerve function tests and thus seemed to indicate more severe neuropathy. At diagnosis, 38% of a cohort of newly diagnosed MB leprosy patients had recent or new reactions or nerve damage at the time of intake into the study. The main risk factor for neuropathy found in this baseline analysis was the presence of skin lesions overlying nerve trunks. They increased the risk of sensory or motor impairment in the concerned nerve by 3-4 times. For some nerves, reactional signs in the lesions further increased this risk to 6-8 times the risk of those without such lesions. Patients with skin lesions overlying peripheral nerve trunks should be carefully monitored for development of sensory or motor impairment.
AIM: To compare different method(s) to detect peripheral neuropathy in leprosy and to study the validity of the monofilament test (MF) and the voluntary muscle test (VMT) as standard tests of nerve function. DESIGN: A multi-centre cohort study of 303 multibacillary (MB) leprosy patients. METHODS: Newly registered MB patients requiring a full course of MDT were recruited in two leprosy outpatient clinics in North India. Controls were people without leprosy or neurological conditions, attending the dermatological outpatient departments of the same clinics. Nerve function was evaluated electrophysiologically using standard parameters for sensory and motor nerve conduction (NC) testing, warm and cold detection thresholds (W/CDT), vibration perception thresholds, dynamometry, MF and VMT. The latter two defined the outcomes of sensory and motor impairment. RESULTS: 115 patients had nerve damage or a reaction of recent onset at diagnosis. Sensory and motor amplitudes and WDTs were the most frequently abnormal. Among the nerves tested, the sural and posterior tibial were the most frequently impaired. In the ulnar nerve, sensory latencies were abnormal in 25% of subjects; amplitudes in 40%. Ulnar above-elbow motor conduction velocities were abnormal in 39% and amplitudes 32%. WDTs were much more frequently affected than CDTs in all nerves tested. The thresholds of all test parameters differed significantly between controls and patients, while only some differed between patients with and without reaction. Good concordance was observed between MF results and sensory latencies and velocities (direct concordance 80% for the ulnar). However, a proportion of nerves with abnormal MF results tested normal on one or more of the other tests or vice versa. Concordance between VMT and motor conduction velocities was good for the ulnar nerve, but for the median and peroneal nerves, the proportion impaired by VMT out of those with abnormal motor conduction was very low. CONCLUSIONS: Concordance between monofilaments and other sensory function test results was good, supporting the validity of the monofilaments as standard screening test of sensory function. Concordance between VMT results and motor nerve conduction was good for the ulnar nerve, but very few median and peroneal nerves with abnormal conduction had an abnormal VMT. A more sensitive manual motor test may be needed for these nerves. Of the nerve assessment tests conducted, NC amplitudes and warm sensation were the most frequently affected. Therefore, nerve conduction studies and WDT measurements appear to be most promising tests for early detection of leprous neuropathy. The pattern of concordance between tactile and thermal sensory impairment failed to support the hypothesis that small fibre neuropathy always precedes large fibre damage. Warm sensation was more frequently affected than cold sensation. This could indicate that unmyelinated C fibres are more frequently affected than small myelinated Asigma fibres.
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Leprosy remains an important health problem worldwide. The disease is caused by a chronic granulomatous infection of the skin and peripheral nerves with Mycobacterium leprae. The clinical range from tuberculoid to lepromatous leprosy is a result of variation in the cellular immune response to the mycobacterium. The resulting impairment of nerve function causes the disabilities associated with leprosy. This review summarises recent advances in understanding of the biology of leprosy, clinical features of the disease, the current diagnostic criteria, and the new approaches to treatment of the infection and the immune-mediated complications. Supervised multi-drug therapy (MDT) for fixed durations is highly effective for all forms of the disease. The widespread implementation of MDT has been associated with a fall in the prevalence of the leprosy but as yet no reduction in the case-detection rate globally. Thus, leprosy control activities must be maintained for decades to interrupt transmission of infection.
The ILEP nerve function impairment and reaction research programme (INFIR 2) was a group of clinical trials conducted to identify second-line treatments for severe leprosy type 1 reactions (T1R). This paper presents the clinical results of one of these trials in which azathioprine was used in combination with short-course prednisolone to ascertain if the combination was effective in controlling the symptoms and signs of reaction. Forty patients were alternately assigned to a 12-week treatment with either AP (12 weeks azathioprine at 3mg/kg/d plus 8 week reducing course prednisolone starting at 40mg/d) or P (12-week reducing course prednisolone starting at 40mg/d). Evaluation included serial quantitative clinical assessments. The overall frequency of side effects was similar in both groups. Results show that there was no difference in clinical outcome in the AP and P groups and a similar number of patients in each group required extra prednisolone for worsening clinical features. We conclude that a 12-week course of azathioprine at 3mg/kg/day plus an 8 week reducing course of prednisolone starting at 40mg/d is as effective as a 12 week reducing course of prednisolone starting at 40mg/d and that the combination therapy is well-tolerated in severe leprosy T1R patients.
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To investigate genetic diversity in a bacterial population, we measured the copy numbers of simple sequence repeats, or microsatellites, in Mycobacterium leprae from patients living in and around Hyderabad, India. Three microsatellite loci containing trinucleotide or dinucleotide repeats were amplified from infected tissues, and the copy numbers were established by sequence analysis. Extensive diversity was observed in a cross-sectional survey of 33 patients, but closely related profiles were found for members of a multicase family likely to share a common transmission source. Sampling of multiple tissues from single individuals demonstrated identical microsatellite profiles in the skin, nasal cavity, and bloodstream but revealed differences at one or more loci for M. leprae present in nerves. Microsatellite mapping of M. leprae represents a useful tool for tracking short transmission chains. Comparison of skin and nerve lesions suggests that the evolution of disease within an individual involves the expansion of multiple distinct subpopulations of M. leprae.
This study demonstrates the presence of IL-10 and IL-6, by immunohistochemistry, in the skin lesions of patients with Type 1 reactions. Fifteen patients with Type 1 reaction from Hyderabad, India were included in this study. They were all receiving standardized treatment for Type 1 reactions: a reducing course of daily oral prednisolone for 6 months. Biopsies were taken before treatment and during treatment at weeks 1, 4, and 6 months. IL-13 was observed in the lesions of most patients. By week 4 of treatment, the presence of IL-13, IL-10, and IL-6 in the lesions had decreased significantly. Although some patients showed significant clinical skin sign improvement within one week of therapy, no concomitant decrease or increase in any of the cytokines was observed at this time point. Interestingly, some cytokine activity within the lesions was observed after 6 months of treatment.