Sun-Mi Kim

Nosocomial Transmission of Severe Fever With Thrombocytopenia Syndrome in Korea

Of the 27 healthcare workers (HCWs) who had contact with a fatally ill patient with severe thrombocytopenia syndrome in Korea (SFTS), 4 who were involved in cardiopulmonary resuscitation complained of fever and were diagnosed with SFTS via seroconversion. Exposure to respiratory secretions, blood, or gowns soiled by body fluids was significantly associated with infection of HCWs.

Diagnostic performance of T-SPOT.TB for extrapulmonary tuberculosis according to the site of infection

BACKGROUNDnThe clinical manifestations of extrapulmonary tuberculosis (E-TB) vary according to site of disease, so we tested the hypothesis that IFN-γ producing T-cell responses also vary in parallel. Therefore we conducted a prospective, blinded, observational study to evaluate the diagnostic performance of blood T-SPOT.TB according to the various sites of E-TB.nnnMETHODSnFrom April 2008 to August 2010, all patients with suspected E-TB were enrolled at a tertiary hospital in an intermediate TB-burden country. Final diagnosis in patients with suspected E-TB was classified by clinical category.nnnRESULTSnA total of 368 patients with suspected E-TB were enrolled; 196 (53%) were classified as having TB, including 119 (32%) with confirmed TB, 34 (9%) probable TB, and 43 (12%) possible TB; the remaining 172 (47%) were classified as not having TB. After excluding patients with possible TB, the T-SPOT.TB was more sensitive in patients with chronic forms of E-TB such as lymph node or osteoarticular TB (93%, 95% CI 83%-97%) than in patients with acute forms of E-TB such as TB meningitis or miliary TB (79%, 95% CI 66%-87%, Pxa0=xa00.03).nnnCONCLUSIONSnThe diagnostic performance of the blood T-SPOT.TB differs among patients with various clinical manifestations of E-TB.

Indeterminate T-SPOT.TB Test Results in Patients with Suspected Extrapulmonary Tuberculosis in Routine Clinical Practice

Background The two interferon-γ release assays such as QuantiFERON-TB Gold / In-Tube (QFT-TB) and T-SPOT.TB-are useful tools for the rapid diagnosis of tuberculosis (TB) but can yield indeterminate test results (ITRs). While some studies have identified risk factors for ITRs in the QFT-TB test, there have been few such studies for the T-SPOT.TB test. The aim of this study was to investigate the risk factors associated with ITRs in the T-SPOT.TB test. Materials and Methods From April 2008 to August 2010, all patients with suspected extrapulmonary tuberculosis (E-TB) were enrolled in a tertiary hospital in Korea. ITR was defined as < 20 spots in the positive control well or > 10 spots in the negative control well. Results Out of a total of 368 patients, 32 (8.7%, 95% CI, 6.0% to 11.7%) had ITRs in their T-SPOT.TB tests. The ITRs were due to a low mitogen response in 13 (40.6%) patients and to a high nil response in the other 19 (59.4%) patients. Statistical analysis revealed that old age, underlying diseases, immunosuppressive treatment, lymphopenia, and clinical manifestations of E-TB were not significantly associated with ITRs. Conclusions Indeterminate results in the T-SPOT.TB test are not affected by age, underlying disease, immunosuppressive treatment, lymphopenia, or clinical manifestations of E-TB, which are known risk factors for indeterminate results in the QFT-TB test.

Rapid diagnosis of tuberculous peritonitis by T cell-based assays on peripheral blood and peritoneal fluid mononuclear cells.

OBJECTIVESnThe utility of a newly-developed Mycobacterium tuberculosis-specific enzyme-linked immunosorbent spot (ELISPOT) assay for diagnosis of tuberculous peritonitis (TBP) has not been fully assessed.nnnMETHODSnAll patients with suspected TBP in a tertiary care hospital in an intermediate TB burden country were prospectively enrolled over a 30-month period. ELISPOT assays were performed on peripheral mononuclear cells (PBMC) and mononuclear cells from peritoneal fluid (PF-MC).nnnRESULTSnSixty-four patients with suspected TBP were enrolled. Of these, 30 (47%) were classified as having TBP (27 confirmed and 3 probable cases), and 25 (39%) were classified as not having active tuberculosis. The remaining 9 (14%) with possible TBP were excluded from the final analysis. Five (8%) of the total 64 patients gave indeterminate PBMC ELISPOT results and 7 (18%) of 39 patients who underwent PF-MC ELISPOT assay revealed indeterminate PF-MC ELISPOT results. The sensitivity and specificity, respectively, of the tested methods for diagnosing TBP were as follows: PBMC ELISPOT (≥ 6 spots), 86% and 67%; PF-MC ELISPOT (≥ 14 spots), 92% and 86%; PF-MC ELISPOT/PBMC ELISPOT ratio (≥ 2), 75% and 93%; and PF ADA levels (≥ 38 IU/L), 95% and 100%. The areas under the receiver operating characteristics curves were as follows: PF-MC ELISPOT, 0.96; PF ADA, 0.96; PBMC ELISPOT, 0.88; and PF-MC ELISPOT/PBMC ELISPOT ratio, 0.87, respectively.nnnCONCLUSIONSnAlthough the ELISPOT assay does not outperform PF ADA, the ELISPOT assay using PBMC and PF-MC is a useful adjunct for diagnosing TBP, especially for a rule-in test when PF/MC/PBMC ELISPOT ratio (≥ 2) is used. However, the relatively high proportion of indeterminate results limits test utility, so further studies are needed to develop an optimized assay prototype.

Diagnostic Usefulness of a T-Cell–Based Assay in Patients With Miliary Tuberculosis Compared With Those With Lymph Node Tuberculosis

Forty-three patients with miliary tuberculosis were evaluated for diagnostic usefulness of enzyme-linked immunospot (ELISPOT) assay. Among noninvasive rapid tests available within 3-5 days, ELISPOT had the highest sensitivity (93%), compared with acid-fast bacilli stain (sputum, 32% and bronchoalveolar lavage, 7%), Mycobacterium tuberculosis polymerase chain reaction (sputum, 53% and bronchoalveolar lavage, 36%), and tuberculin skin test (22%). In comparison with 44 patients with lymph node tuberculosis, the sensitivity of the ELISPOT assay in patients with miliary tuberculosis (93%) was as high as in those with lymph node tuberculosis (95%, P = .63), whereas the sensitivity of the tuberculin skin test was substantially lower in patients with miliary tuberculosis (22%) than in those with lymph node tuberculosis (73%, P < .001).

Isoniazid treatment to prevent TB in kidney and pancreas transplant recipients based on an interferon-γ-releasing assay: an exploratory randomized controlled trial

BACKGROUNDnWe performed a randomized trial of isoniazid treatment based on interferon-γ-releasing assay (IGRA) in kidney transplant (KT) recipients in an intermediate-TB-burden country.nnnMETHODSnAll adult patients admitted to a KT institute between June 2010 and May 2013 were enrolled. The IGRA (T-SPOT.TB assay) was performed on all patients, and isoniazid treatment was given to those with clinical risk factors for latent TB infection (LTBI). Patients with positive IGRA who had no clinical risk factors for LTBI were randomly assigned to isoniazid treatment or a control group. The development of TB after KT was monitored between June 2010 and November 2013. The primary endpoint was the development of TB.nnnRESULTSnOf the 784 patients who had no clinical risk factors for LTBI, 445 (57%) gave negative results in the IGRA, 76 (10%) indeterminate results and 263 (33%) positive results. Of the latter, 131 were allocated to isoniazid treatment and 132 to the control group. Three (2%) of the control group developed TB, whereas none of the isoniazid treatment group developed TB (rate difference 1.22 per 100 person-years, Pu200a=u200a0.09). Of the 521 patients with negative or indeterminate IGRA results, 4 [0.8%, 0.43 per 100 person-years (95% CI 0.12-1.09)] developed TB after KT.nnnCONCLUSIONSnIGRA-based isoniazid treatment has a trend towards reducing TB development in KT recipients without clinical risk factors, but careful monitoring of TB development is needed in negative-IGRA KT recipients.

Diagnostic Usefulness of Cytomegalovirus (CMV)-Specific T Cell Immunity in Predicting CMV Infection after Kidney Transplantation: A Pilot Proof-of-Concept Study

Background Cytomegalovirus (CMV) is one of the most important opportunistic infections in transplant recipients. Currently sero-positivity for CMV IgG before solid organ transplantation is the laboratory test of choice for stratifying the risk of CMV reactivation after solid organ transplantation. Theoretically, CMV-specific cell-mediated immune responses before solid organ transplantation should further categorize patients as high or low risk of CMV development. We therefore evaluated the usefulness of the CMV-specific enzyme-linked immunospot (ELISPOT) assay in kidney transplant (KT) candidates for predicting the development of CMV infections after transplantation. Materials and Methods All adult CMV IgG (+) recipients admitted to the KT institute between March 2014 and June 2014 were enrolled, and CMV infections after KT were observed between March 2014 and December 2014. All patients underwent CMV pp65 and IE1-specific ELISPOT assays before transplantation. CMV infection was defined in the presence of CMV antigenemia, CMV syndrome, or tissue-invasive CMV disease. We used the data to select optimal cut-off values for pp65 and IE1, respectively, on ROC curves. Results A total of 69 transplant recipients involving 54 (78%) living-donor KT, 9 (13%) deceased-donor KT, 3 (4%) kidney-pancreas transplants, and 3 (4%) pancreas transplants were enrolled. Of the 69 patients, 27 (39%) developed CMV infections. There was no association between the IE1-specific ELISPOT assay and CMV infection. However, only 15 (31%) of the 48 patients with positive pp65-specific ELISPOT results (>10 spots/2.0 × 105 cells) developed CMV infections, whereas 12 (57%) of the 21 patients with negative pp65-specific ELISPOT results developed CMV infection (P = 0.04). Conclusion Negative pp65-specific ELISPOT assay results before transplantation appear to predict the subsequent development of CMV infections after transplantation in CMV IgG (+) KT recipients. Therefore, risk stratification of CMV IgG (+) recipients using the CMV-specific ELISPOT, together with preventive strategies, may further reduce CMV development.

A rapid and non-invasive 2-step algorithm for diagnosing tuberculous peritonitis using a T cell-based assay on peripheral blood and peritoneal fluid mononuclear cells together with peritoneal fluid adenosine deaminase

OBJECTIVESnA recently developed RD-1 gene-based assay for diagnosing tuberculous peritonitis (TBP) has given promising results. We therefore created a clinical algorithm for differentiating TBP from other diagnoses using peripheral blood and peritoneal fluid mononuclear cells (PBMC/PF-MC) along with conventional tests.nnnMETHODSnAll adult patients with suspected TBP in whom enzyme-linked immunosorbent spot (ELISPOT) assays were performed both on PBMC and PF-MC were prospectively enrolled over a 6-year period. Confirmed TBP with positive cultures or Mycobacterium tuberculosis PCR, probable TBP with PF changes consistent with TBP, caseating granuloma, and a successful response to anti-TB therapy, as well as possible TBP without exclusion of TBP, were each defined.nnnRESULTSnA total of 74 patients were enrolled. Of these, 45 (61%) (19 confirmed, 16 probable, and 10 possible) were classified as TBP. The other 29 (39%) patients were classified as not TB. The sensitivity and specificity, respectively, of the tested methods for diagnosing TBP were as follows: PBMC ELISPOT (≥6 spots), 84% and 59%; PF-MC ELISPOT (≥6 spots), 87% and 86%; PF-MC/PBMC ratio (≥3), 69% and 97%; and PF-ADA level (≥21 U/L), 82% and 79%. The areas under the ROC curves were as follows: PF-MC ELISPOT, 0.90; PF-MC/PBMC ratio, 0.82; PBMC ELISPOT, 0.80; and PF-ADA, 0.80, respectively. When a 2-step algorithm (PBMC ELISPOT ≥6 spots or PF-ADA ≥21 U/L as a rule-out test and PF-MC/PBMC ratio ≥3 as a rule-in test) was applied, 67% (30/45) of the patients with TBP were accurately classified without undergoing invasive procedures.nnnCONCLUSIONSnA 2-step algorithm using the PBMC/PF-MC ELISPOT assays and PF-ADA appears to be a promising rapid and non-invasive approach for diagnosing TBP.

Living donor and recipient screening for latent tuberculosis infection by tuberculin skin test and interferon-gamma releasing assay in a country with an intermediate burden of tuberculosis

There are few data on donor screening for latent tuberculosis infection (LTBI) using the tuberculin skin test (TST) and interferon-gamma releasing assay (IGRA). In South Korea, most renal allografts involve living donors (average, 80xa0%). Hence, we have an opportunity to evaluate donor and recipient screening for LTBI by TST and IGRA. All donors and recipients admitted for kidney transplantation during a 20-month period were evaluated prospectively by using TST and Mycobacterium tuberculosis-specific enzyme-linked immunosorbent spot (ELISPOT) assay. The study population consisted of 205 living donor–recipient pairs (≥16xa0years) including 15 (7xa0%) who yielded indeterminate donor or recipient ELISPOT results. Of the 205 donors, 63 (31xa0%) gave a positive TST ≥5xa0mm, 33 (16xa0%) a positive TST ≥10xa0mm, and 96 (47xa0%) a positive ELISPOT. Of the 205 recipients, 9 (5xa0%) gave a positive TST ≥5xa0mm, 3 (2xa0%) a positive TST ≥10xa0mm, and 79 (39xa0%) had a positive ELISPOT. Of the 205 donor–recipient pairs, only 59 (29xa0%) gave negative donor and recipient ELISPOT results and 139 (68xa0%) negative donor and recipient TSTs (<5xa0mm) (Pxa0<xa00.001). One third of donor–recipient pairs tends to be positive in the TST, and two thirds of the donor–recipient pairs tends to be positive in the ELISPOT. Given the high positive rate of LTBI obtained by screening donors, further studies on the clinical value of solid organ transplant donors with positive TST or ELISPOT and health economics analysis in countries with intermediate burden of TB are needed for policy decisions on isoniazid (INH) prophylaxis.

Diagnostic usefulness of T-cell based assays for tuberculous meningitis in HIV-uninfected patients.

OBJECTIVESnEarly diagnosis and treatment of tuberculous meningitis (TBM) is essential for a positive outcome, but sensitive, specific, and rapid diagnostic tests for TBM are lacking. We evaluated the diagnostic utility of enzyme-linked immunosorbent spot (ELISPOT) assays in HIV-uninfected patients with suspected TBM.nnnMETHODSnAll HIV-uninfected patients with suspected TBM were prospectively enrolled at a tertiary care hospital in an intermediate TB-burden country, during a 6-year period. ELISPOT assays were performed on peripheral blood mononuclear cells (PBMC) and cerebrospinal fluid-mononuclear cells (CSF-MC).nnnRESULTSnOf the 276 evaluable patients, 90 (33%) were classified as having TBM (30 definite cases, 19 probable, and 41 possible), and 186 (67%) as having non-TBM. When comparing definite TBM versus non-TBM, the sensitivity and specificity of the PBMC ELISPOT assay (≥6 spots; manufacturers recommended cut-off) for diagnosing TBM were 96% (95% CI, 82-100) and 58% (95% CI, 50-66), respectively. The CSF-MC ELISPOT assay (≥38 spots; receiver operating characteristic [ROC]-derived cut-off) was a useful rule-in test with specificity of 95% (96% CI, 90-98). Its sensitivity was 68% (95% CI, 45-86), which was superior those of AFB smear microscopy (14%; P < 0.001) and CSF Mycobacterium tuberculosis PCR (41%; P = 0.07). Combining this assay with M. tuberculosis PCR, clinical score, and both together increased sensitivity to 86%, 91%, and 95%, respectively, while retaining about 95% specificity.nnnCONCLUSIONSnThe CSF-MC ELISPOT assay appears to be a rapid and accurate rule-in test for the diagnosis of TBM and a useful adjunct for diagnosing TBM in HIV-uninfected patients.