Tuberculosis screening in dialysis patients--is the tuberculin test effective?

AIM: Patients with end-stage renal disease are at increased risk for tuberculosis (TB). The Centers for Disease Control and Prevention (CDC) has recommended annual skin testing for TB, with tuberculin-purified protein derivative (PPD), in patients with chronic renal failure. The aim of this study was to identify the incidence and prevalence oftuberculin positivity and assess the utility of the tuberculin test in an inner city dialysis population. METHODS: All patients on chronic hemodialysis at a center affiliated to the University of Chicago, who were tuberculin-tested between 1997 and 2000 or had previously documented PPD positivity precluding retesting, were included. Demographics, comorbidity, and tuberculin and anergy reactivity were recorded. A positive PPD was an induration of > 10 mm in response to 5 tuberculin units of PPD, and anergy an induration of < 2 mm in response to the anergy antigens (Candida and Mumps), at 48 h. PPD-positive patients were compared with PPD-negative patients; Fisher's exact test and t-test were used, p < 0.05 was considered significant. RESULTS: Of 131 patients at the dialysis center, 118 were studied. The remaining 13 refused consent to PPD testing. 41 (35%) were PPD-positive, 77 (65%) were negative. Of the 77 PPD-negative patients, 62 (81%) were anergic. None of the PPD-positive patients had clinical or radiographic signs of active TB. Only 20 patients received INH prophylaxis, the others refused or had contraindications to therapy. The conversion rate ranged from 3 - 8% per year. Demographics, nutritional parameters, comorbidity and adequacy of dialysis did not help predict PPD positivity. CONCLUSION: There is a high prevalence of PPD positivity and anergy among dialysis patients. As the diagnostic utility of the time-tested PPD test is unclear in an anergic dialysis population, the need for a high index of suspicion for active tuberculosis and timely diagnostic work up should be reinforced and not replaced by total dependence on the tuberculin test.     

Tuberculin skin test results and the booster phenomenon in two-step tuberculin skin testing in hemodialysis patients

Patients with chronic renal failure are at increased risk for tuberculosis (TB). Centers for Disease Control and Prevention (CDC) have recommended annual skin testing for TB, with tuberculin-purified protein derivative (PPD), in patients with chronic renal failure. Uremia alters the macrophage function, which can lead to anergy for skin tests. The aim of this prospective study was to determine the prevalence of positive tuberculin skin test (TST) and the booster effect of TST in hemodialysis patients living in a relatively underdeveloped portion of the country. Material and Methods. Patients were recruited from Van (Yuzuncu Yil University Hospital, Yuksek Ihtisas Hospital) and the Mus State Hospital). At the time of this study, a total of 143 patients were under hemodialysis treatment in these hemodialysis centers, and among them, 124 were included in the study. Informed consent was obtained before inclusion in the study. A positive PPD was an induration of >10 mm in response to five tuberculin units of PPD (RT23-Tween 80), at 72 h. TST-negative patients received a booster TST 10 days later, approximately 10 cm away from the previous intracutaneous injection. The test dose could not be increased due to unavailability of this kind of preparation. The test was performed and interpreted in the same way. Skin testing was performed in June and December 2003. Patients with known active TB are not included in the study. Testing was not done in hospitalized patients to rule out effects of other disease states. Results. Mean age of the patients was 45.3 +/- 16 (range 13-82) years. All patients were on HD treatment twice (n: 14) or three times (n: 110) weekly. Duration of dialysis before TST was 30 +/- 17 (12-84) months. With the first test (n: 14), 11.3% of the patients showed a positive reaction; the second test added (n: 15) 12.1% more TST-positive patients, reaching a total of (n: 29) 23.4% of the patients with a positive TST. The     

Tuberculosis in renal transplants in Rio de Janeiro

Retrospective analysis of 982 renal transplants over 21 years (1981 to 2002) sought to evaluate the prevalence of tuberculosis (TB). This analysis included 74 patients: 30 with a past TB history, who had INH prophylaxis since the beginning of immunosuppression, and 44 who only became TB infected after receiving transplants. The diagnosis of TB was made by a compatible medical situation with bacteriological/histological confirmation, which when not possible, underwent a therapeutic test occur. The average time for the illness to surge was 3 years. The mortality rate was 34.9% (15/44). Patients with hepatitis C were more affected. Among those who used INH prophylaxis only one contracted TB, showing that the drug displayed a protection rate of 96.6% (29/30).     

A Prospective Longitudinal Study Evaluating the Usefulness of a T‐Cell‐Based Assay for Latent Tuberculosis Infection in Kidney Transplant Recipients

We evaluated whether ELISPOT assay can predict tuberculosis (TB) development in kidney‐transplantation (KT) recipients with a negative tuberculin skin test (TST). All adult patients admitted to a KT institute between June 2008 and December 2009 were enrolled; TB development after KT was observed between June 2008 and December 2010. Isoniazid (INH) was given to those patients with positive TST or clinical risk factors for latent TB infection (LTBI). ELISPOT assay was performed on all patients, and TB development after KT was observed by a researcher blinded to the results of ELISPOT. A total of 312 KT recipients including 242 (78%) living‐donor KT were enrolled. Of the 312 patients, 40 (13%) had positive TST or clinical risk factors for LTBI and received INH; none developed TB after KT. Of the remaining 272 patients, 4 (6%) of 71 with positive ELISPOT assay developed TB after KT, whereas none of the 201 patients with negative (n = 171) or indeterminate ELISPOTs (n = 30) developed TB after KT (rate difference between positive and negative/indeterminate ELISPOT, 3.3 per 100 person‐years [95% CI 1.4–5.1, p<0.001]). Positive ELISPOT results predict subsequent development of TB in KT recipients in whom LTBI cannot be detected by TST or who lack clinical risk factors for LTBI.     

The affecting factors and comparison of tuberculin skin test in peritoneal dialysis and hemodialysis patients

Compared with the general population, patients with chronic renal failure have increased tuberculosis (TB) prevalence and mortality rates. In this study, we aimed to investigate tuberculin skin test (TST) positivity rates in hemodialysis (HD) and peritoneal dialysis (PD) patients and the factors influencing TST positivity. Ninety-two HD patients and 44 PD patients who had been on HD and PD treatment for at least 3 months were recruited into the study. TST was administered in all patients. Positivity was defined as an induration diameter >10 mm. At least 5 mm of induration following skin testing together with a chest radiography indicating previous infection was defined as latent TB infection. TST positivity rates, diameter of TST indurations, and serum albumin levels in HD patients were higher than the PD patients. TST induration size was not correlated with any other parameters in both HD and PD groups. TST-positive patients had higher albumin levels and lower leukocyte count than the TST-negative patients. In TST-positive patients, albumin level was correlated with the duration of dialysis but TST induration size was not correlated with the lymphocyte count and albumin level. In our study, TST positivity of patients was found in 30.4% of HD patients, 9% of PD patients, and 23.5% of total patients. It is still recommended to use TST for the screening test of TB. We found a significant relationship between TST and albumin level. It should be remembered that TST response may be lower in PD patients, especially in cases in which TB is suspected.     

The Affecting Factors and Comparison of Tuberculin Skin Test in Peritoneal Dialysis and Hemodialysis Patients

Compared with the general population, patients with chronic renal failure have increased tuberculosis (TB) prevalence and mortality rates. In this study, we aimed to investigate tuberculin skin test (TST) positivity rates in hemodialysis (HD) and peritoneal dialysis (PD) patients and the factors influencing TST positivity. Ninety-two HD patients and 44 PD patients who had been on HD and PD treatment for at least 3 months were recruited into the study. TST was administered in all patients. Positivity was defined as an induration diameter >10 mm. At least 5 mm of induration following skin testing together with a chest radiography indicating previous infection was defined as latent TB infection. TST positivity rates, diameter of TST indurations, and serum albumin levels in HD patients were higher than the PD patients. TST induration size was not correlated with any other parameters in both HD and PD groups. TST-positive patients had higher albumin levels and lower leukocyte count than the TST-negative patients. In TST-positive patients, albumin level was correlated with the duration of dialysis but TST induration size was not correlated with the lymphocyte count and albumin level. In our study, TST positivity of patients was found in 30.4% of HD patients, 9% of PD patients, and 23.5% of total patients. It is still recommended to use TST for the screening test of TB. We found a significant relationship between TST and albumin level. It should be remembered that TST response may be lower in PD patients, especially in cases in which TB is suspected.     

Comparison of QuantiFERON-TB Gold With Tuberculin Skin Test for Detection of Latent Tuberculosis Infection Before Kidney Transplantation

Introduction

Screening for latent tuberculosis infection (LTBI) before kidney transplantation (KT) is an indispensable process, purposes of this study were to compare the QuantiFERON-TB Gold In-Tube test (QFT-GIT) with the tuberculin skin test (TST) for screening of LTBI in kidney transplant recipients (KTRs).

Methods

We compared prospectively the results of QFT-GIT with TST in 97 KTRs screened for LTBI between July 2008 and July 2012. Isoniazid (INH) prophylaxis was applied to KTRs with a positive TST or positive QFT-GIT or clinical risk factors for LTBI. Post-transplant tuberculosis (TB) was diagnosed by clinical evidence.

Results

The mean patients follow-up was 24.6 ± 14.4 months. Positive results on QFT-GIT and TST was obtained among 19 (20.4%) and 12 (12.9%) subjects, respectively, an overall agreement of 79.3% (κ = 0.27, 95% confidence interval [CI] −0.03–0.50; P < .014). The incidence of TB was 0.52 per 100 person-years (95% CI 0.02–3.68). None of the patients in the INH prophylaxis group developed TB, whereas 1 in the no prophylaxis group developed disease at 14 months after KT. Sensitivity of the 2 tests could not be compared because patients who showed positive results on QFT-GIT or TST did not develop TB. The difference of specificity between QFT-GIT (79.3%) and TST (86.9%) was not significant (P = .l67). Abnormal chest radiographs (odds ratio [OR] 27.94, 95% CI 1.22–636.61, P = .037) and positive TST (OR 7.65, 95% CI 1.75–33.30, P = .007) showed significant associations with positive QFT-GIT results. Only positive QFT-GIT (OR 6.03, 95% CI 1.51–24.01, P = .011) showed an association with positive TST results.

Conclusions

QFT-GIT and TST for diagnosis of LTBI in KTRs showed reasonable concordance but no superiority of either test.     

Prospective randomised trial of isoniazid prophylaxis in renal transplant recipient

Renal transplantation (RT) recipients are at a high risk of developing tuberculosis (TB) following transplantation. Effectiveness of isoniazid (INH) in preventing TB is well documented in immunocompetent as well as immunocompromised persons. There is paucity of data on role of INH prophylaxis in RT recipients. Thus, a prospective randomised trial of INH in RT recipients was carried out to determine the efficacy of daily INH monotherapy in the prevention of TB in these patients. Patients of end stage renal disease (ESRD) taken for RT formed the subjects of study. Patients with active TB and active hepatitis at the time of RT were excluded from the study. Patients were randomised to receive INH 300 mg with pyridoxine 20 mg daily from the day of RT. The duration of the treatment was planned for 1 year or till the development of TB, which ever was earlier. Between October 1998 and September 2000, 114 RT were done at our hospital. Of these, 24 (21%) patients had active TB at the time of RT and thus were excluded. Patients included were randomised with 1:2 ratio of treatment and control group. Of the 90 patients thus enrolled, 30 were randomised in treatment group and 60 in control group. Of the included patients five patients had very early graft loss (three in treatment and two in control group) within days and thus excluded from the analysis. Three of the 27 (11.1%) patients in treatment group and 15 (25.8%) in control group developed TB (P = 0.10). The risk ratio of (RR) of INH versus control group of TB was 0.36 (95% CI, 0.10–1.32) but the difference was not statistically significant (P = 0.12). Only one patient developed INH induced hepatitis. In conclusion, with INH prophylaxis, there was a trend towards protection from TB, though it was not statistically significant. Further, all patients tolerated INH and hepatotoxicity was not a major problem in this group of patients.     

Efficacy of isoniazid prophylaxis in renal allograft recipients

The efficacy of isoniazid (INH) prophylaxis in renal allograft recipients who are on long-term immunosuppression in a region highly prevalent for tuberculosis (TB) was studied. INH (300 mg/d in patients weighing more than 35 kg and 5 mg/kg/d in patients with <35 kg body weight) together with Pyridoxine 50 mg/d for 1 year was started in randomly assigned renal allograft recipients. Occurrence of clinical tuberculosis during the initial 2 years posttransplantation was observed in the risk group and patients at no risk. Risks were defined as acute rejection episodes and exposure to antirejection therapy, past history of TB completely or incompletely treated, radiological evidence of past tuberculosis, history of tuberculosis in close contacts. Among 480 patients registered in the study, INH prophylaxis was given to 219 randomly assigned renal allograft recipients. Results were compared among patients developing TB during the initial 2 years posttransplantation in both the groups. Risk factors were analyzed for comparison in both groups. No significant difference was observed in terms of past history of TB, TB in close contacts, episodes of acute rejection during the initial 3 months, and comorbidities such as cytomegalovirus infection, hepatitis C virus infection, and posttransplant diabetes. One patient from the INH group and 10 patients from the non-INH group developed TB during the initial 2 years posttransplantation (P < .0001). None of patients required discontinuation of INH. INH was observed to be safe and effective as a chemoprophylactic agent in renal allograft recipients.     

慢性肾功能衰竭患者结核感染预防治疗的指征探讨

观察了８３０例慢性肾功能衰竭患者长期随访过程中结核感染的发生情况，以探讨这类患者预防性抗结核治疗的指征。由此提示，具有前三项中一项或一项以上因素的慢性肾衰患者应视为结核感染的高危人群而给予预防性抗结核治疗。     

Comparison of the 2-step tuberculin skin test and the quantiFERON-TB Gold In-Tube Test for the screening of tuberculosis infection before liver transplantation

The ability of interferon-gamma release assays (IGRAs) to detect latent tuberculosis (TB) infection before liver transplantation (LT)is not well established. The aims of this study were (1) to compare the ability of the tuberculin skin test (TST) and the QuantiFERON-TB Gold In-Tube (QFT-IT) test (a whole-blood IGRA) to diagnose latent TB infections in patients awaiting LT and (2) to correlate the results with the severity of liver disease. We conducted a prospective, cross-sectional study of patients who were evaluated for LT between July 2008 and July 2010. The 95 patients who were included underwent the 2-step TST and the QFT-IT test. The mean Model for End-Stage Liver Disease (MELD) score was 13.8. Forty-four patients (46.3%) had positive TST results, 42 (44.2%) had positive QFT-IT results, and 2 (2.1%) had indeterminate QFT-IT results. Simultaneous TST and QFT-IT testing yielded a positivity rate of 55.8% [95% confidence interval (CI) = 45.3-65.9] with either test, and the 2-step TST yielded a positivity rate of 46.3% (95% CI = 36.1-56.8); the difference was 9.5% (P = 0.004). In an adjusted analysis, the rates for positive TST results were lower in patients with MELD scores > or = 18 [odds ratio (OR) = 0.2, 95% CI = 0.04-0.7], lower in Child-Pugh-Turcotte (CPT) class C patients versus CPT class A patients (OR = 0.1, 95% CI = 0.02-0.6), and higher in males (OR = 6.4, 95% CI = 1.9-22.0). In contrast, only being male (OR = 3.5, 95% CI = 1.1-11.0) was associated with positive QFT-IT results; no association was found with the MELD score (OR = 0.8, 95% CI = 0.2-2.8) or the CPT class (OR = 0.3; 0.05-1.4). In conclusion, the QFT-IT test is better than the TST for detecting latent TB infection in patients with more advanced liver disease. Our results support the regular use of the QFT-IT test for screening patients with end-stage liver disease for latent TB infection before LT.     

Value of the tuberculin skin test in screening for tuberculosis in dialysis patients

BACKGROUND: Hemodialysis patients are at high risk for tuberculosis, and a tuberculin skin test (TST) is not usually helpful in detecting tuberculosis infection because of anergic reactions. Prophylactic therapy against tuberculosis in dialysis patients is important to enhance transplantation success. Herein we evaluated the value of TST in screening for tuberculosis and analyzed any compounding factors that might affect the results of the test in hemodialysis patients in an endemic area of Turkey. METHODS: A total of 187 (96 female, 91 male) patients were screened using a 2-step TST. Test results were compared with clinical, radiologic, and laboratory data. RESULTS: None of the patients had active tuberculosis during the study and 55% had been vaccinated against tuberculosis. After the first purified protein derivative (PPD) test, 55.1% of the patients showed a positive reaction, ultimately reaching a total of 68.4% following the second test. Cumulative positive TST results were significantly correlated with male gender (P=.001, r=.352), previous tuberculosis history (P=.013, r=.183) positively, whereas with the ferritin level (P=.001, r=-.233) negatively; but there were no significant relationships between TST results and other data. CONCLUSIONS: Impairment of delayed-type hypersensitivity reaction is frequent in dialysis patients, but we observed high rates of positivity with the two-step TST which could be attributed to tuberculosis being endemic in Turkey. Further comparative studies with more specific diagnostic methods will be helpful to evaluate the importance of TST positivity in identifying tuberculosis-infected HD patients.     

The value of tuberculin skin testing in haemodialysis patients.

BACKGROUND: Chronic haemodialysis patients are at increased risk for developing tuberculosis (TB). Appropriate screening methods to detect latent Mycobacterium tuberculosis infection are required. The aim of this prospective multi-centre study was to evaluate the tuberculin skin test (TST) as a screening method for detection of M.tuberculosis infection in haemodialysis patients. METHODS: A total of 224 patients in two haemodialysis centres were prospectively tested, using 2 units of tuberculin PPD RT23. Up to three booster injections were given with a 7 day interval to patients not responding to the previous test. The results were compared with clinical and radiological data. RESULTS: The cumulative prevalence of a positive TST was 14.7% for the first test, 27.8% for the second test and 32.6% for the fourth test. There was no influence of age, gender, haemodialysis centre, dialysis efficiency, nutritional state, levels of zinc, vitamin D therapy, primary renal disease, (previous or active) immunosuppressive therapy or response to hepatitis B vaccination. There was a significant, but weak, correlation between TST positivity and a history of positive TST or TB. Chest radiography and positive TST were not correlated, yet a positive chest X-ray increased the detection of patients with latent M.tuberculosis infection up to 47.8%. CONCLUSIONS: In haemodialysis patients, a positive response of >30% to repeated TST was obtained. Two consecutive TSTs were sufficient to recruit most of the booster reactions. Since only a weak correlation was found with anamnestic data, regular TST evaluation in combination with a chest X-ray, is a useful tool to detect infection with M.tuberculosis in haemodialysis patients.     

Tuberculin skin test and anergy in dialysis patients of a tuberculosis-endemic area

BACKGROUND/AIM: Uremic patients are at an increased risk of being affected by tuberculosis (TB). Periodical tuberculin skin tests were suggested to detect TB-infected patients. These were replaced by chest radiographs in endemic areas like Taiwan. However, almost 50% of the TB incidence in dialysis patients was extrapulmonary. In this study, we tried to investigate the value of tuberculin tests in dialysis patients in endemic areas. METHODS: The patients were recruited from our dialysis unit. Purified protein derivative (PPD) and control tests with antigens for Candida and toxoid were performed using the Mantoux method. PPD with >10-mm induration will be considered positive. Skin anergy meant that the indurations of all antigens were less than 5 mm. A follow-up was done 12 months after the tests. RESULTS: A total of 177 patients were evaluated. Anergy was found in 40 patients (22.6%). A positive predictor of anergy was age >45 years (p = 0.03), while a negative predictor was prealbumin >20 mg/dl (p = 0.04). Fifty-three patients (30%) had positive PPD tests. Seven of the positive PPD patients (13.2%) developed active TB during the following years. Among the 40 patients with skin anergy, 6 (15%) were found to have active TB. Of the 48 patients (21.1%) with indurations of the PPD tests between 5 and 10 mm, none was found to have active TB. CONCLUSION: Although anergy will influence the sensitivity of PPD tests, these tests in combination with anergy tests could help to establish the diagnosis of TB in uremic patients, even in TB-endemic areas.     

Diagnosis and treatment of latent tuberculosis infection in liver transplant recipients in an endemic area

BACKGROUND: Treatment of latent tuberculosis infection (LTBI) with isoniazid is recommended for transplant recipients with positive tuberculin skin test (TST). However, TST could be an imperfect identifier of LTBI in this population. In addition, the risk of isoniazid hepatotoxicity could be high in liver transplant recipients (LTR). A retrospective cohort study was performed to evaluate the diagnosis and treatment of LTBI in LTR. METHODS: Charts of all 547 patients who received primary liver transplantation at a University Hospital in Spain between 1988 and 1998 were reviewed. RESULTS: TST was performed in 373 patients (71%) before transplantation. The result was positive in 89 (24%). The median follow-up after transplantation was 49 months. None of the TST-positive patients developed tuberculosis (TB), but 5 out of 284 patients with negative TST (1.76%) had active TB (P=0.6). Twenty-three patients received isoniazid as treatment of LTBI according to the decision of the attending physician. None of these patients developed TB, but 4 of them (17%) presented isoniazid hepatotoxicity. Among patients who did not receive isoniazid, 2 out of 21 (9.52%) with radiologic previous TB developed active TB versus 0.44% (2/452) among the remaining patients (relative risk [RR], 27.8, 95% CI, 3.2-147). CONCLUSIONS: Treatment of LTBI with isoniazid can not be recommended to LTR on the basis of a positive TST because it is an imperfect identifier of patients at risk of TB. LTR with radiologic features of previous TB are at higher risk of posttransplant active TB. Isoniazid-related hepatotoxicity is more frequent among LTR than in the general population.     

Tuberculin positivity: A serious problem before transplantation in Turkey

Chronic renal failure (CRF) patients are at increased risk of tuberculosis. Detecting latent tuberculosis infection is essential before transplantation. The tuberculin skin test is the only validated method for the diagnosis of latent tuberculosis infection and for screening for hypersensitivity. The aim of this study was to assess the tuberculin test status (5 Todd units tuberculin) of 164 asymptomatic transplant candidates and correlate it with anamnestic data and laboratory values of patients awaiting transplantation. Skin test positivity was higher among older age subjects (r = .294, P = .0001). The cumulative prevalence rates of tuberculin positivity and anergy were 42.1% (69 patients) and 43.3% (71 patients), respectively. Only 14.5% of the positive patients had a previous tbc history; 15.9% had a family history of tbc. Among peritoneal dialysis (PD) patients, the rate of anergic skin tests was higher, while positivity was higher among patients who were preparing for preemptive renal transplantation (P = .009). In conclusion, there was a high prevalence of tuberculin positivity and anergy among asymptomatic pretransplant CRF patients. CRF patients who are awaiting transplantation especially should meet evaluations for previous tbc anamnesis and family history. Elderly subjects showed a higher risk for purified protein derivate positivity.     

Tuberculosis in Egyptian kidney transplant recipients: study of clinical course and outcome

BACKGROUND: Tuberculosis (TB) is an important infection encountered post-transplantation especially in developing countries, with high incidences of morbidity and mortality. In this report, we study the risk factors and impact of TB on the outcome of kidney transplantation. METHODS: Of 1200 live-donor Egyptian kidney transplantations, 45 (3.8%) patients developed post-transplant TB. Of these, five had had TB pre-transplantation and 40 were male. The mean age was 32.6 +/- 10.5 years. Primary immunosuppression treatment for 39 (86.7%) patients was cyclosporine (CsA). RESULTS: The mean time interval between transplantation and TB diagnosis was 49.8 +/- 41.5 (range 2-180) months. In 86.7% of patients, TB was diagnosed one year post-transplantation. Urinary TB was the most common form (53%), while pleuropulmonary TB accounted for 38%. All post-transplant TB patients received a triple anti-tuberculous therapy (rifampicin, ethambutol and INH) with a favorable response in all but two patients who needed another 24-month course. Hepatotoxicity was seen in 11 patients, eight were mild with normalization after temporary withdrawal of rifampicin, and three cases were severe, but mortality was not attributable to hepatocellular failure. Twelve patients died, 11 of them due to unrelated causes. Chronic rejection occurred in more than half of the patients (55.6%), of whom 24 (96%) were CsA-treated, which can be attributed to rifampicin/CsA interaction. More than 35% of TB patients lost their graft as a result. Pre-transplant tuberculosis patients had a comparable post-transplant course. CONCLUSIONS: TB is a common infection in renal transplant recipients with a peak incidence occurring one year post-transplant. Chronic rejection is a serious complication that had a negative impact on the graft survival, especially in CsA-treated recipients. INH prophylaxis is safe in pre-transplant TB. The post-transplantation outcome in the pre-transplant tuberculosis patients is no different from non-TB patients.     

Antibody to hepatitis C virus increases with time on hemodialysis.

We studied whether chronic hemodialysis is associated with an increased risk of exposure to hepatitis C virus. Utilizing a first generation Elisa assay (C-100 Elisa, Ortho Diagnostic Systems, Raritan, NJ) and the Chiron RIBA HCV second generation assay (RIBA, Chiron, Emeryville, CA and Ortho Diagnostic Systems, Raritan, NJ), antibody to HCV was found in 31 of 87 hemodialysis patients (36%). Patients on hemodialysis less than 2 years had an antibody incidence of 15% (n = 46), as contrasted with a 59% incidence for patients on dialysis greater than or equal to 2 years (n = 41). We were unable to demonstrate a correlation of HCV-antibody positivity with history of blood transfusion. The overall incidence is higher than previously reported for hemodialysis patients in the United States. The very high incidence found in patients on dialysis greater than or equal to 2 years suggests that factors in the hemodialysis unit might contribute to the spread of virus.     

Performance of a whole blood interferon gamma assay for detecting latent infection with Mycobacterium tuberculosis in children

BACKGROUND: The diagnosis of latent Mycobacterium tuberculosis (MTB) infection with a tuberculin skin test (TST) in children is complicated by the potential influence of prior exposure to Bacille Calmette Geurin (BCG) vaccination or environmental mycobacteria. A whole blood assay has recently been developed to quantitatively measure interferon gamma (IFN-gamma) production by lymphocytes specific to the MTB antigens ESAT-6 and CFP-10, but its use and assessment in children has been limited. A study was undertaken to compare the performance of the whole blood IFN-gamma assay with the TST in diagnosing latent tuberculosis (TB) infection or TB disease in children in routine clinical practice. METHODS: One hundred and six children with a high risk of latent TB infection or TB disease were enrolled in the study. High risk was defined as contact with TB disease, clinical suspicion of TB disease, or recent arrival from an area of high TB prevalence. The whole blood IFN-gamma assay was undertaken in 101 children. RESULTS: Seventeen (17%) of the 101 assays yielded inconclusive results due to failure of positive or negative control assays. There was poor correlation between the whole blood IFN-gamma assay and the TST (kappa statistic 0.3) with 26 (70%) of the 37 children defined as latent TB infection by TST having a negative whole blood IFN-gamma assay. There were no instances of a positive whole blood IFN-gamma assay with a negative TST. Mitogen (positive) control IFN-gamma responses were significantly correlated with age (Spearman's coefficient = 0.53, p<0.001) and, in children with latent TB infection identified by TST, those with a positive IFN-gamma assay were older (median 12.9 v 6.92 years, respectively, p = 0.007). The whole blood IFN-gamma assay was positive in all nine children with TB disease. CONCLUSION: There was poor agreement between the whole blood IFN-gamma assay and TST for the diagnosis of latent TB. The whole blood IFN-gamma assay may have lower sensitivity than the TST in diagnosing TB infection in children. A significant proportion of whole blood IFN-gamma assays fail when used as a screening assay in routine practice.     

Clinical Characteristics and Risk Factors of Early-Onset Tuberculosis After Liver Transplantation

BackgroundWe encountered some cases of early-onset tuberculosis (TB) after liver transplant (LT), leading to further transmission to other immunocompromised patients. Therefore, we investigated the clinical characteristics and risk factors of early-onset TB after LT.MethodsAll adult patients with TB after LT from 1996 to 2019 were retrospectively enrolled. Our hospital did not screen for latent TB infection (LTBI) in LT recipients because of concerns regarding the potential hepatotoxicity of anti-TB medication. Patients were categorized into 2 groups based on the TB onset time after LT: early-onset TB (≤2 months) and late-onset TB (>2 months).ResultsOf 4301 LT recipients, 91 patients developed TB after LT (2.1%). The median time from LT to TB development was 9.4 months. Of these 91 patients, 11 were classified as having early-onset TB (12.1%). Patients with early-onset TB had a greater pretransplant TB history than patients with late-onset TB (36.4% vs 11.3%, P = .048).ConclusionThis unusual early-onset TB was more common in patients with a pretransplant TB history, suggesting the possibility of missed TB or full manifestation of the indolent course of TB after LT. Therefore, LT recipients with a pretransplant TB history should undergo thorough screening for active TB and consider prophylaxis.