Adoptive transfer of cell-mediated immunity to tuberculin using RNA from tuberculin-sensitive subjects.
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Adoptive transfer of delayed hypersensitivity skin test response to tuberculin with 'immune' RNA extracted from the sensitized lymphocytes of a healthy subject or a patient with Hodgkin's disease was successfully demonstrated in previously non-sensitive patients with neoplastic diseases including Hodgkin's disease. 'Non-immune' RNA obtained from non-sensitive man, on the other hand, failed to transfer PPD skin reactivity in non-sensitive recipients. 'Immune' RNA-mediated PPD skin test response remained positive for a considerable period of time, indicating that the effect of 'immune' RNA is systemically active. 'Immune' RNA was found to be RNase-sensitive but DNase-resistant. In vitro adoptive transfer of delayed hypersensitivity with 'immune' RNA, as assayed by lymphocyte transformation test, was unsuccessful. (+info)
Cervical tuberculous lymphadenopathy: changing clinical pattern and concepts in management.
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Tuberculosis is one of the biggest health challenges the world is facing. In this study the clinical pattern of patients with cervical lymphadenitis, who presented to the ear, nose, and throat outpatient department of the Government Medical College Hospital, Chandigarh, India between June 1997 and May 1998 is recorded. Tuberculosis accounted for 60 out of 94 cases of cervical lymph node enlargement. The commonest age group affected was 11-20 years. Constitutional symptoms were not present in most of the patients. Multiple matted nodes were seen in 23 patients but a single discrete node was seen in 18 patients. Upper deep jugular nodes were the most commonly affected lymph nodes. Discharging sinus and abscess formation were uncommon. Fine needle aspiration cytology yielded a positive diagnosis in 52 out of 56 patients. Chest lesions on radiography were evident in 16% of the patients. Mantoux test was positive and was more than 15 mm in most of the patients. This study shows that the classical picture of "scrofula" is no longer seen nowadays and can probably be explained by the earlier presentation of the disease. All the patients were treated with short course daily chemotherapy for six months. Surgery was not required in the majority of patients except in four cases where excision biopsy was performed. Patients with abscess formation were managed with wide bore needle aspiration only. With a minimum six month period of follow up, no patient was found to have a recurrence of local or systemic disease. This study emphasises the role of fine needle aspiration cytology in diagnosis and confirms the efficacy of six months short course chemotherapy. (+info)
Suppression of tuberculin skin reactivity by prior tuberculin skin testing.
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In two consecutive studies, eighteen and forty-one normal subjects were given a standard tuberculin skin test of 1 tuberculin unit (0.02 mug of PPD). Two days later another skin test was given. Readings of the skin reactions showed that subjects exhibiting strongly positive skin reactions in their primary skin tests showed a significantly smaller indurations in their primary skin tests tended to have equal or larger areas of induration after the secondary skin tests. These observations are discussed in relation to the possible existence of regulatory mechanisms of cell-mediated immune reactions. (+info)
Cell-mediated immune response to tuberculosis antigens: comparison of skin testing and measurement of in vitro gamma interferon production in whole-blood culture.
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Although delayed-type hypersensitivity skin testing with tuberculin purified protein derivative (PPD) is the standard for tuberculosis screening, its variability suggests the need for a more sensitive, noninvasive test. An in vitro whole-blood assay has been proposed as an alternative. Using health care worker volunteers, we confirmed the correlation between PPD skin test (PPD-ST) results (positive, induration of >15 mm) and a standardized gamma interferon (IFN-gamma) assay, QuantiFERON-TB (Q-IFN), manufactured by CSL Biosciences in Australia, and we evaluated Mycobacterium tuberculosis culture subfractions as potential substitutes for PPD. Twenty healthy volunteers with positive PPD-ST results and 20 PPD-ST-negative controls were enrolled. Whole blood was cultured with human PPD antigens (HuPPD), Mycobacterium avium complex (MAC) PPD, phytohemagglutinin (PHA), and four M. tuberculosis culture subfractions: low-molecular-weight culture, filtrate, culture filtrate without lipoarabinomannan, soluble cell wall proteins, and cytosolic proteins, all developed from M. tuberculosis strain H(37)RV. Secretion of IFN-gamma (expressed as international units per milliliter) was measured by an enzyme immunoassay. The PPD or subculture fraction response as a percentage of the PHA response was used to determine positivity. Sixteen of 20 PPD-ST-positive individuals were classified as M. tuberculosis positive by Q-IFN, and 1 was classified as MAC positive. Sixteen of 20 PPD-ST-negative individuals were M. tuberculosis negative by Q-IFN, 2 were MAC positive, and 2 were M. tuberculosis positive. The tuberculosis culture subfractions stimulated IFN-gamma production in PPD-ST-positive volunteers, and significant differences could be seen between the two PPD-ST groups with all subfractions except soluble cell wall protein; however, the response was variable and no better than the Q-IFN PPD. The agreement between the Q-IFN test and the PPD-ST was good (Cohen's kappa = 0.73). The Q-IFN assay can be a useful tool in further studies of immune responses to M. tuberculosis antigens. (+info)
The impact of media-based health education on tuberculosis diagnosis in Cali, Colombia.
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Tuberculosis (TB) is one of the most worrying infectious diseases facing less developed countries. Diagnosis and treatment of those who are transmitting Mycobacterium tuberculosis is considered a very effective control strategy. Within this strategy the priority is to achieve high cure rates before attempting to increase case finding. However, there is a dearth of research on how to increase case finding and diagnostic coverage in those settings where high cure rates are being achieved. This paper presents an evaluation of the impact on case finding of a mass media health education campaign for TB control in Cali, Colombia. The campaign aimed at increasing case finding and reducing levels of prejudice against people with TB. The impact assessment shows that the campaign produced an increase of 64% in the number of direct smears processed by the laboratories and an increase of 52% in the number of new cases of positive pulmonary TB, with respect to the previous period. Unfortunately, the effects of the campaign were short-lived. These findings have at least two important implications. First, passive case finding is likely to be an insufficient strategy to reach the operational targets of diagnostic coverage. Secondly, providing basic information about the earliest symptoms of TB and the procedures for diagnosis can increase diagnostic coverage, and thus strengthen the effect on infection risk of control programmes with high cure rates. Further research is required to identify other strategies that could, first, increase diagnostic coverage and, secondly, make the intervention effects sustainable. (+info)
Comparing the adrenaline-Pirquet test with international PPD tuberculin tests.
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Several tuberculins, strengths and setting methods are in everyday use. We wanted to compare the Norwegian reference adrenaline Pirquet test with the internationally recommended Mantoux PPD test and Rhoditest. In responders of a random sample of young adults, with randomization of test subjects, we intra-individually compared the adrenaline-Pirquet (aP) test with Norwegian-produced synthetic medium tuberculin (SMT) with either the Mantoux test with PPD 2 tuberculin units (TU) (M2), the Mantoux-PPD 5 TU (M5) or the PPD 2 TU-Rhoditest (Rh). The criteria for a positive reaction were > or = 4mm for the aP test, > or = 10 mm for the M2 test, > or = 6 mm for the M5 test and > or = 2 mm for the Rh test. Strongly positive reactions were defined as aP test > or = 10 mm and M2/M5 test > or = 15 mm. One of the tuberculin tests was positive while the comparison test was negative in 14% of the M2 test group (n = 236), 15% in the M5 test group (n = 162) and 20% in the Rh test group (n = 187). The three PPD tests had positive reactions 3-10 times as often, with a simultaneous negative aP test, than vice versa. Strongly positive reactions occurred in 7% of the aP tests (> or = 10 mm), 32% of the M2 tests (> or = 15 mm) and in 41% of the M5 tests (> or = 15 mm). Receiver operating characteristic (ROC) curves gave the best agreement, with aP test >3mm compared with the M2 and the Rh tests. Regression equations are presented for transformations of the Norwegian reference method of adrenaline-Pirquet results to internationally recommended PPD tests. The international recommendations, globalization in general and the skill of Norwegian public health nurses in performing intra-dermal BCG suggest a future shift to the PPD 2 TU Mantoux test in Norway. Due to the lack of sensitivity and specificity of all tuberculin tests they might be used in targeted tuberculin testing and not as a general screening procedure in a low-incidence tuberculosis area with BCG-vaccinated inhabitants. (+info)
Comparison of purified protein derivatives and effect of skin testing on results of a commercial gamma interferon assay for diagnosis of tuberculosis in cattle.
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Purified protein derivatives (PPD) prepared in the USA were compared with those prepared in Australia by a private company (CSL Veterinary) for use with a commercial gamma interferon (gamma-IFN) assay for diagnosis of bovine tuberculosis. The effect of skin testing on results of the gamma-IFN assay was determined, and results were compared when blood samples were stimulated with PPD within 2 hours and after 24 hours of sample collection. Twenty cattle that were sensitized by subcutaneous injection of heat-killed Mycobacterium bovis were randomly divided into 3 groups. Cattle in group A were tested with the caudal fold skin test (CFT) on day 0 and the comparative cervical skin test (CCT) on day 7. Cattle in group B were tested with the CFT on day 0 and the CCT on day 63, and group C cattle were not skin tested. Blood samples for the gamma-IFN assay were collected at various times throughout the study period. Optical density (OD) values for the gamma-IFN assay were not significantly different when blood samples were stimulated with US avian PPD and CSL avian PPD. However, OD values were significantly higher for US bovine PPD than for CSL bovine PPD. However, the final interpretation of the gamma-IFN assay was usually the same when using either US or CSL PPD. In addition, OD values for the gamma-IFN assay were significantly higher for blood samples collected after sensitized cattle were skin tested than for samples collected from the same cattle before skin testing or from cattle not skin tested. The OD values for blood samples stimulated within 2 hours of sample collection were significantly higher than for samples stimulated 24 hours after sample collection. However, OD values for all PPD-stimulated samples from sensitized cattle were significantly higher in samples collected 3 days after skin testing and stimulated 24 hours after collection than for samples from the same animals collected before skin testing and stimulated within 2 hours of sample collection. Results of this study indicate that PPD prepared in the USA or Australia can be used to stimulate blood samples for the gamma-IFN assay. Skin testing cattle prior to collection of blood for the gamma-IFN assay boosts production of gamma-IFN by lymphocytes from cattle that have had prior exposure to M. bovis antigens. Use of the gamma-IFN assay in conjunction with skin testing may improve detection of cattle infected with M. bovis. In addition, the increase in production of gamma-IFN after skin testing will permit greater flexibility in conducting the assay because samples can be stimulated after they have been shipped overnight rather than only on the day of sample collection. (+info)
Tuberculin skin testing of physicians at a midwestern teaching hospital: a 6-year prospective study.
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The epidemiology of tuberculin reactivity among physicians practicing in regions of moderate tuberculosis prevalence is unknown. We prospectively assessed the epidemiology of tuberculin skin test (TST) reactivity among physicians in training in St. Louis between 1992 and 1998. Of 1574 physicians who were tested, 267 (17%) had positive TST results. Older age, birth outside of the United States, prior bacille Calmette-Guerin (BCG) vaccination, and practice in the fields of medicine, anesthesiology, or psychiatry were associated with a positive TST result. Among physicians born in the United States, 63 (5.7%) had positive TST results. Among physicians with > or = 2 documented TSTs, 12 had conversion to a positive TST (1.6%; 1.03 conversions per 100 person-years). Physicians in this study had a high rate of tuberculin reactivity, despite a low conversion rate. The relationship between TST conversion and birth outside of the United States and BCG vaccination suggests a booster phenomenon rather than true new TST conversions. (+info)