Mycobacterium tuberculosis infection in allogeneic bone marrow transplantation patients

Latent tuberculosis in adult hematopoietic stem cell transplantation recipients: Clinical experience from a previously endemic population

Hematopoietic stem cell transplantation (HSCT) recipients may be at an elevated risk of developing active tuberculosis infection due to suppression in the cellular immune system. Herein, we aimed to evaluate the prevalence of latent tuberculosis and active tuberculosis in patients with allogeneic and autologous HSCT. In this cohort, data were obtained retrospectively from patients' records. The patients who were followed up in the bone marrow transplantation unit of the University of Health Sciences Dr Abdurrahman Yurtaslan Ankara Oncology Education and Research Hospital between January 2016 and December 2019 were screened for the study. And the HSCT recipients who had tuberculin skin test and/or QuantiFERON-TB gold (QFT-GIT) test results were included in the study. A total of 361 patients were included in the study, 227 patients had autologous HSCT, and 134 patients had allogeneic HSCT. QFT-GIT was performed in 10 patients with allogeneic HSCT, and it was found positive in only 1 patient. Tuberculin skin test ≥5 mm was accepted as positive and was accepted to have latent tuberculosis, and it was positive in 18.2% (41) of the patients with autologous HSCT and was positive in 21.6% (29) of the patients with allogeneic HSCT. There was no significant difference between the 2 groups (P = .429). Isoniazid (INH) prophylaxis was started in 16.7% of patients with autologous HSCT and 22.4% of patients with allogeneic HSCT. During follow-up, active tuberculosis did not develop in any patients in both groups. There was no statistically significant difference found between allogeneic and autologous HSCT recipients regarding the prevalence of latent tuberculosis. Active tuberculosis infection did not develop in any of the patients who started INH prophylaxis. INH prophylaxis seems to be very efficient in preventing the reactivation of latent tuberculosis in patients going through allogeneic HSCT and/or autologous HSCT.

Tuberculosis in Pediatric Solid Organ and Hematopoietic Stem Cell Recipients

Children undergoing solid organ and hematopoietic stem cell transplantation are at high risk of morbidity and mortality from tuberculosis (TB) disease in the post-transplant period. Treatment of TB infection and disease in the post-transplant setting is complicated by immunosuppression and drug interactions. There are limited data that address the unique challenges for the management of TB in the pediatric transplant population. This review presents the current understanding of the epidemiology, clinical presentation, diagnosis, management, and prevention for pediatric transplant recipients with TB infection and disease. Further studies are needed to improve diagnosis of TB and optimize treatment outcomes for these patients.

An update on Mycobacterium tuberculosis infection after hematopoietic stem cell transplantation in adults

BACKGROUND

Mycobacterium tuberculosis (TB) is common worldwide, but is rarely reported after hematopoietic transplantation (HSCT). We reviewed all TB cases among HSCT since 2010 to provide an update on its epidemiology, clinical presentation, management and outcome.

METHODS

Several databases were reviewed from January 1, 2010 to June 30, 2018 using key words tuberculosis and hematopoietic transplantation.

RESULTS

The 47 cases of TB were reported during the study period. The highest TB frequency was reported from India (2.9%), with a median frequency of 2% (range, 0.18%-2.9%). The majority were recipients of allogeneic transplants (45/47, 95.7%). Pulmonary TB was the most common clinical presentation (20/47, 42.6%). The median time to clinical presentation was 4.6 (range, 3-12.9) and 2.4 (range, 0.6-5) months, based on cohort data and case reports, respectively. Fever was reported in 87.5% (14/16) of patients. First-line quadruple drug therapy was frequently used (29/35, 82.9%), with a median length of 12 and 9 months for cohorts and case reports, respectively. All-cause and attributable mortality was 27.6% (13/47), and 8.5% (4/47), respectively.

CONCLUSIONS

Mycobacterium tuberculosis presents early after HSCT, most commonly as fever. A high index of suspicion is needed for early diagnosis and treatment, to prevent TB-attributable mortality.

Tuberculosis and Transplantation

Mycobacterium tuberculosis is a major opportunistic pathogen in transplant recipients. Compared to that in the general population, the frequency of tuberculosis (TB) is 10 to 40 times higher in hematopoietic stem cell transplant (HSCT) recipients and 20 to 74 times higher in solid-organ transplant (SOT) recipients. Transplant recipients with TB are also more likely to develop disseminated disease, have longer time to definitive diagnosis, require more invasive diagnostic procedures, and experience greater anti-TB treatment-related toxicity than the general population. Specific risk factors for TB in SOT recipients include previous exposure to M. tuberculosis (positive tuberculin skin tests and/or residual TB lesions in pretransplant chest X ray) and the intensity of immunosuppression (use of antilymphocyte antibodies, type of basal immunosuppression, and intensification of immunosuppressive therapy for allograft rejection). Risk factors in HSCT recipients are allogeneic transplantation from an unrelated donor; chronic graft-versus-host disease treated with corticosteroids; unrelated or mismatched allograft; pretransplant conditioning using total body irradiation, busulfan, or cyclophosphamide; and type and stage of primary hematological disorder. Transplant recipients with evidence of prior exposure to M. tuberculosis should receive treatment appropriate for latent TB infection. Optimal management of active TB disease is particularly challenging due to significant drug interactions between the anti-TB agents and the immunosuppressive therapy. In this chapter, we address the epidemiology, clinical presentation, diagnostic considerations, and management strategies for TB in SOT and HSCT recipients.

The demanding attention of tuberculosis in allogeneic hematopoietic stem cell transplantation recipients: High incidence compared with general population

BACKGROUND

The risk of developing tuberculosis (TB) in allogeneic hematopoietic stem cell transplantation (HSCT) recipients is expected to be relatively high in an intermediate TB burden country. This single-center retrospective study was conducted to investigate risk factors and the incidence of TB after allogeneic HSCT.

METHODS

From January 2004 to March 2011, 845 adult patients were enrolled. Starting April 2009, patients were given isoniazid (INH) prophylaxis based on interferon-γ release assay results. The incidence of TB was analyzed before and after April 2009, and compared it with that of the general population in Korea.

RESULTS

TB was diagnosed in 21 (2.49%) of the 845 allogeneic HSCT patients. The median time to the development of TB was 386 days after transplantation (range, 49-886). Compared with the general population, the standardized incidence ratio of TB was 9.10 (95% CI; 5.59-14.79). Extensive chronic graft-versus-host disease (GVHD) was associated with the development of TB (P = 0.003). Acute GVHD, conditioning regimen with total body irradiation and conditioning intensity were not significantly related. INH prophylaxis did not reduce the incidence of TB (P = 0.548). Among 21 TB patients, one patient had INH prophylaxis.

CONCLUSION

Allogeneic HSCT recipients especially those who suffer from extensive chronic GVHD are at a high risk of developing TB. INH prophylaxis did not statistically change the incidence of TB, however, further well-designed prospective studies are needed.

Human and Mouse Hematopoietic Stem Cells Are a Depot for Dormant Mycobacterium tuberculosis

An estimated third of the world's population is latently infected with Mycobacterium tuberculosis (Mtb), with no clinical signs of tuberculosis (TB), but lifelong risk of reactivation to active disease. The niches of persisting bacteria during latent TB infection remain unclear. We detect Mtb DNA in peripheral blood selectively in long-term repopulating pluripotent hematopoietic stem cells (LT-pHSCs) as well as in mesenchymal stem cells from latently infected human donors. In mice infected with low numbers of Mtb, that do not develop active disease we, again, find LT-pHSCs selectively infected with Mtb. In human and mouse LT-pHSCs Mtb are stressed or dormant, non-replicating bacteria. Intratracheal injection of Mtb-infected human and mouse LT-pHSCs into immune-deficient mice resuscitates Mtb to replicating bacteria within the lung, accompanied by signs of active infection. We conclude that LT-pHSCs, together with MSCs of Mtb-infected humans and mice serve as a hitherto unappreciated quiescent cellular depot for Mtb during latent TB infection.

Infections Caused by Mycobacterium tuberculosis in Recipients of Hematopoietic Stem Cell Transplantation

Mycobacterium tuberculosis (M. tuberculosis) infections are uncommon in recipients of hematopoietic stem cell transplantation. These infections are 10-40 times commoner in recipients of stem cell transplantation than in the general population but they are 10 times less in stem cell transplantation recipients compared to solid organ transplant recipients. The incidence of M. tuberculosis infections in recipients of allogeneic stem cell transplantation ranges between <1 and 16% and varies considerably according to the type of transplant and the geographical location. Approximately 80% of M. tuberculosis infections in stem cell transplant recipients have been reported in patients receiving allografts. Several risk factors predispose to M. tuberculosis infections in recipients of hematopoietic stem cell transplantation and these are related to the underlying medical condition and its treatment, the pre-transplant conditioning therapies in addition to the transplant procedure and its own complications. These infections can develop as early as day 11 and as late as day 3337 post-transplant. The course may become rapidly progressive and the patient may develop life-threatening complications. The diagnosis of M. tuberculosis infections in stem cell transplant recipients is usually made on clinical grounds, cultures obtained from clinical specimens, tissues biopsies in addition to serology and molecular tests. Unfortunately, a definitive diagnosis of M. tuberculosis infections in these patients may occasionally be difficult to be established. However, M. tuberculosis infections in transplant recipients usually respond well to treatment with anti-tuberculosis agents provided the diagnosis is made early. A high index of suspicion should be maintained in recipients of stem cell transplantation living in endemic areas and presenting with compatible clinical and radiological manifestations. High mortality rates are associated with infections caused by multidrug-resistant strains, miliary or disseminated infections, and delayed initiation of therapy. In recipients of hematopoietic stem cell transplantation, isoniazid prophylaxis has specific indications and bacillus Calmette-Guerin vaccination is contraindicated as it may lead to disseminated infection. The finding that M. tuberculosis may maintain long-term intracellular viability in human bone marrow-derived mesenchymal stem cells complicates the development of effective vaccines and strategies to eliminate tuberculosis. However, the introduction of linezolid, cellular immunotherapy, and immunomodulation in addition to autologous mesenchymal stem cell transplantation will ultimately have a positive impact on the overall management of infections caused by M. tuberculosis.

Tuberculosis in hematopoietic stem cell transplant recipients

Literature on tuberculosis (TB) occurring in recipients of Hematopoietic Stem Cell Transplant (HSCT) is scanty even in countries where TB is common. Most reports of TB in HSCT patients were from ASIA, in fact the TB incidence ranging from 0.0014 (USA) to 16% (Pakistan). There are few reports of TB diagnosis during the first two weeks after HSCT; most of cases described in the literature occurred after 90 days of HSCT, and the lung was the organ most involved. The mortality ranged from 0 to 50% and is higher in allogeneic HSCT than in autologous. There is no consensus regarding the screening with tuberculin skin test or QuantiFERON-TB gold, primary prophylaxis for latent TB, and whether the epidemiologic query should be emphasized in developing countries with high prevalence of TB.

Tuberculosis in hematopoietic stem cell transplant patients: case report and review of the literature

The literature describing tuberculosis (TB) in hematopoietic stem cell transplant (HSCT) recipients is scant, even in countries where TB is common. We describe a case of pulmonary TB in a patient who underwent HSCT and review the English language literature on this subject. An extensive PubMed and Ovid search was undertaken for the period January 1980 to March 2009; the search terms used were 'Mycobacterium tuberculosis' or 'tuberculosis', in combination with 'hematopoietic stem cell transplantation' or 'bone marrow transplantation'. The patient in the present case report underwent allogeneic transplantation and developed TB 8 days after his HSCT. The patient had received vaccination against TB in childhood. During the year prior to the HSCT he had had contact with a relative who had pulmonary TB. On day 3 of anti-TB treatment he developed pericarditis. The patient received anti-TB treatment for 6 months without major problems. From the literature review, we found 34 related studies, 25 on the clinical manifestations of TB. Most of the reports were from Asia (48%), and the incidence of TB varied from 0.0014% in the USA to 16% in Pakistan. TB occurred at between +21 and +1410 days post-HSCT (257.2 days the median), and the lung was the organ most frequently involved. Mortality varied from 0% to 50% and was higher in allogeneic HSCT. There is no consensus regarding screening with the tuberculin skin test or primary prophylaxis for latent TB, and further research into this is necessary in developing countries with a high prevalence of TB.

Special issues related to hematopoietic SCT in the Eastern Mediterranean region and the first regional activity report

Although several centers are now performing allogeneic hematopoietic SCT (HSCT) in the Eastern Mediterranean (EM) region, the availability is still limited. Special issues including compatible donor availability and potential for alternative donor programs are discussed. In comparison to Europe and North America, differences in patterns of diseases and pre-HSCT general status, particularly for patients with BM failure, are described. Other differences including high sero-positivity for CMV, hepatitis B and C infection, and specific observations about GVHD and its relation to genetically homogeneous communities are also discussed. We report that a total of 17 HSCT programs (performing five or more HSCTs annually) exist in 9 countries of the EM region. Only six programs are currently reporting to European Group for Blood and Marrow Transplantation or Center for International Blood and Marrow Transplantation Research. A total of 7617 HSCTs have been performed by these programs including 5701 allogeneic HSCTs. The area has low-HSCT team density (1.56 teams per 10 million inhabitants vs 14.43 in Europe) and very low-HSCT team distribution (0.27 teams per 10 000 sq km area vs <1-6 teams in Europe). Gross national income per capita had no clear association with low-HSCT activity. Much improvement in infrastructure and formation of an EM regional HSCT registry are needed.

Multi-organ failure due to Mycobacterium tuberculosis and Aspergillus flavus infection after allogeneic bone marrow transplantation

Mycobacterium tuberculosis (MT) is a serious, but rare infectious complication after allogeneic bone marrow transplantation (BMT). We describe a case of fatal sepsis due to MT and Aspergillus flavus after allogeneic BMT for Aplastic Anemia. The diagnosis was made on bone marrow biopsy and asitic fluid culture. Broadspectrum antituberculous and Amphotericin B therapy was started immediately after diagnosis. The patient developed severe hypoxia and finally died of multi-organ failure. Rapid progression of mycobacterial infection as well as fungal infection should be considered in patients post BMT with unexplained fever, particularly in patients from endemic areas.

Infections caused by mycobacterium tuberculosis in patients with hematological disorders and in recipients of hematopoietic stem cell transplant, a twelve year retrospective study

BACKGROUND

Tuberculous infections in patients with hematological disorders and hematopoietic stem cell transplant vary in incidence, complications and response to treatment.

METHODS AND MATERIALS

A retrospective study of patients with various benign and malignant hematological disorders and recipients of hematopoietic stem cell transplant who were treated at Riyadh Armed Forces Hospital, Saudi Arabia between January 1991 and December 2002 and who developed tuberculous infections was conducted.

RESULTS

Tuberculous infections occurred in eighteen patients with hematological disorders and hematopoietic stem cell transplant. The main associated factors were: reduced immunity due to the primary hematological disorder, age more than 50 years and the administration of cytotoxic chemotherapy, steroids or radiotherapy. These infections frequently involved the lungs and predominantly occurred in males and in patients with chronic myeloproliferative disorders, myelodysplastic syndrome and acute myeloid leukemia. In patients treated with intravenous cytotoxic chemotherapy, tuberculous infections tended to occur earlier and also tended to be more disseminated compared to infections occurring in patients treated with oral chemotherapy. Anti-tuberculous treatment was given to 16 patients and it was successful in 15 of these patients.

CONCLUSION

Tuberculous infections cause significant morbidity and mortality in patients with various hematological disorders and in recipients of hematopoietic stem cell transplant. The early administration of anti-tuberculous therapy and compliance with drug treatment are associated with successful outcomes while delayed management, drug resistance and the presence of miliary infections are associated with poor prognosis and high mortality rates.

[Infections in stem cell transplantation]

The morbidity and mortality associated with infections in stem cell transplantation (SCT) has decreased considerably in recent years because of increasing knowledge of related risk factors, immune recovery, and the pattern of infection according to the phase of evolution of SCT, and the introduction of new and more effective antimicrobial agents. These advances, together with the use of peripheral blood stem cells, T-lymphoid cell depletion, stimulating factors, and more potent immunosuppressors has reduced SCT mortality and broadened the indications for this treatment. Nevertheless, infection continues to a prominent complication in these patients.

Tuberculosis in stem cell transplant patients

Tuberculosis (TB) is an increasing health problem, and patients undergoing stem cell transplantation (SCT) are at high risk of acquiring TB. Following a review of the medical literature, this article reports the current situation of TB in SCT patients. A PubMed search was undertaken using the keywords 'tuberculosis', 'stem cell transplantation' and 'bone marrow transplantation', and cases with meaningful data for analysis were included. The medical literature contains relatively few data on TB and SCT. Although there is a risk of TB in allogeneic SCT patients, this is less than in solid organ transplant patients, and the risk in autologous SCT patients is similar to the risk in the general population. The incidence of TB in SCT patients is proportional to the incidence of TB in the general population. Evidence favouring TB prophylaxis is not well established. While allogeneic transplantation carries a risk of TB, this is not true for autologous transplantation. Prophylaxis can only be an option for selected patients or countries with high rates of TB.

GI complications in pediatric patients post-BMT

This retrospective study comprehensively examined hepatic and gastrointestinal complications post-bone marrow transplant (BMT) in a heterogeneous group of 132 pediatric patients that underwent 142 transplants. Hyperbilirubinemia occurred in 28% of this population with clinically evident jaundice in 16%. Acute graft-versus-host disease (GVHD) occurred in 46% of the population, with liver involvement in 39% and intestinal involvement in 60% of those with acute GVHD. Veno-occlusive disease (VOD) occurred in 18% of the population. A greater increase in hepatic transaminases was noted in GVHD and VOD than nonspecific liver injury. Serum bilirubin may help to differentiate between VOD and hepatic GVHD. Biliary sludging occurred in 20% of patients and was associated with increased morbidity. Common post transplant gastrointestinal complications included mucositis in 90%, vomiting in 85% and abdominal pain in 71%. TPN support post transplant was required in 91%. Diarrhea occurred in 67% with the most common identified etiologies reported as GVHD (27%), viral (6%), Clostridium difficile (8%) infections and unknown (28%). Typhilitis developed in 3.5%. Melena or hematochezia occurred in 11 patients (8%). However, gastrointestinal bleeding was disproportionately represented in intensive care unit admissions (5/27) and 100 day mortality (5/21). Gastrointestinal and hepatic complications represent a major cause of morbidity and mortality in pediatric BMT recipients.

[Factors of immunodepression in patients with tuberculosis]

OBJECTIVES

To study the frequency of a factor of immunodepression in patients with tuberculosis, the differences in presentation, and the diagnosis and therapeutic management according to the immune status.

METHODS

Retrospective study of the files of patients hospitalised in the University Hospital Centre of Rennes in 1998 for a Mycobacterium tuberculosis infection. Comparison of two populations, immunodepressed versus non immunodepressed.

RESULTS

75 patients aged 20 to 91 were included, 41 patients were considered immunodepressed and 34 non immunodepressed. The causes of immunodepression were: HIV infection (n = 2), diabetes (n = 4), chronic alcoholism (n = 12), chronic respiratory diseases treated with corticosteroids (n = 6), neoplasia (n = 9), and inflammatory diseases (n = 7). Comparison between the 2 populations revealed more a frequent history of tuberculosis in the immunodepressed (p = 0.04), shorter delay before diagnosis (p = 0.04), greater frequency of disseminated forms (p = 0.02) and enhanced mortality (p = 0.01). There was no difference in the 2 groups with regard to the clinical signs having evoked tuberculosis, the diagnostic method, the bacteriological results or the modalities of treatment.

CONCLUSION

The frequent reactivation of tuberculosis in immunodepressed patients and the severity of the infection in these patients should evoke tuberculosis and the rapid initiation of an efficient treatment in such patients. In the case of alteration in immune defences, prophylactic treatment should help to reduce the number of such reactivations.

Multidrug-resistant tuberculosis in bone marrow transplant recipient

Multidrug-resistant tuberculosis (TB) is an increasing problem worldwide, however only three cases have been previously described in transplant recipients, especially involving lung and heart transplant. We describe a case of multidrug-resistant TB in an allogenic bone marrow transplant recipient with good response to second-line therapy.

Tuberculosis in allogeneic stem cell transplant recipients: still a problem in the 21st century

Allogeneic stem cell transplant (ASCT) recipients have severely impaired cell-mediated immunity as a result of their conditioning regimen, immunosuppressive therapy, and graft-versus-host disease (GVHD). Accordingly, they are susceptible to bacterial, viral, and fungal infections. Mycobacterial infections can also occur in these patients, although the incidence is not high, even in countries where tuberculosis (TB) is common. We describe four patients from our hospital who developed pulmonary T tuberculous infection in the post-transplant period over a 3-year period. During that time a total of 127 patients have undergone an ASCT, representing an incidence of TB of 2.3%. The pretransplant diagnosis was acute myeloid leukemia in three patients and chronic myeloid leukemia in one case. All four patients were treated with a combination of cyclosporine and corticosteroids for acute and/or chronic GVHD. Three of the four patients were born outside Australia, each from an area where TB is endemic. Two patients died within 2 weeks of the commencement of antituberculous therapy, the third is alive and well, and the fourth died of multi-organ failure and sepsis after 4 months in hospital. A higher index of suspicion of previous TB exposure and infection is required in the assessment of ASCT recipients, particularly in those born in areas where TB is common or endemic.

Mycobacterium tuberculosis at a comprehensive cancer centre: active disease in patients with underlying malignancy during 1990-2000

Thirty HIV-seronegative cancer patients with active tuberculosis were evaluated. Eighteen (60%) were immigrants, 19 (63%) had haematological malignancy, and fever was the most common presentation (97%). Of 19 (63%) patients with pulmonary tuberculosis, 11 (58%) were misdiagnosed initially as suffering from cancer following radiography. Death was attributed to tuberculosis for six (21%) of 29 patients who received anti-mycobacterial therapy. All four patients who had received high-dose systemic corticosteroids within 4 weeks of diagnosis of infection died, whereas two (8%) deaths occurred in 25 individuals without corticosteroid exposure (p < 0.001; OR 8.67). At this institution, active tuberculosis was rare, and was seen mostly in immigrants. Recent high-dose corticosteroid therapy is a significant predictor of mortality in cancer patients with tuberculosis.

Infectious complications and outcomes after allogeneic hematopoietic stem cell transplantation in Korea

We reviewed 242 allogeneic hematopoietic stem cell transplantation (HSCT) recipients retrospectively over a 2-year period (January 1998-December 1999) in order to analyze the characteristics and assess the outcomes of infectious complications in patients after HSCT in Korea. Bacteria were the major pathogens before engraftment, and viral and fungal infections predominated during the post-engraftment period. Varicella zoster virus was the most common viral pathogen after engraftment. Cytomegalovirus disease occurred mainly in the late-recovery phase. The frequency of mold infection was higher than that of yeast. There was a relatively high incidence of tuberculosis (3.0%) and Pneumocystis carinii pneumonia (6.5%). One case of death by measles confirmed by autopsy was also noted. Overall, cumulative mortality was 43% (104/242), and 59.6% of these deaths (62/104) were infection-related. Allogeneic HSCT recipients from unrelated donors were prone to infectious complication and higher mortality than those from matched sibling (17/39 (43.6%) vs 45/203 (22.2%), respectively; P<0.01; odd ratio 2.5; 95% confidence interval 1.2-5.1). As infection was the main post-HSCT complication in our data, more attention should be given to the management of infections in HSCT recipients.

Tuberculosis in Hematopoietic Stem Cell Transplant Recipients in Korea

Hematopoietic stem cell transplantation (HSCT) results in impaired cell-mediated immunity, which subsequently increases the risk of infection from bacterial, fungal, and viral pathogens. Mycobacterial infections are commonly seen in immunodeficient patients, especially in endemic areas. Several series that have reviewed mycobacterial infections in HSCT patients reported incidences varying from less than 0.1% to 5.5%. From February 1996 to July 2003, we retrospectively reviewed records of 295 adult patients who underwent HSCT at Samsung Medical Center, Korea. Mycobacterial infections were diagnosed in 9 (3.1%) of the 295 transplant recipients. The time from HSCT to tuberculosis (TB) infection ranged from 45 days to 165 days posttransplantation. Analysis at the univariate level indicated that a conditioning regimen with total body irradiation (TBI), chronic graft-versus-host disease, and a previous history of TB infection were significant risk factors for the development of TB infection after HSCT. Multivariate analysis revealed that only a previous history of TB infection and TBI increased the risk of TB infection in HSCT patients (relative risk, 4.8 and 12.5, respectively). Isoniazid prophylaxis in HSCT recipients with only radiologic findings suggestive of past inactive TB infection did not significantly alter the incidence of TB infections (P = .236). In conclusion, a previous history of active TB infection and TBI were significant risk factors of TB infection following HSCT, and isoniazid prophylaxis may benefit HSCT recipients with a previous history of active TB infection.

Pulmonary tuberculosis in a child receiving intensive chemotherapy for acute myeloblastic leukemia

The authors describe a 6-year-old boy who developed pulmonary tuberculosis during intensive chemotherapy for acute myeloblastic leukemia (AML). The diagnosis of tuberculosis was made by PCR from an open lung biopsy, while a bacterial culture was negative. The patient was treated with triple tuberculostatic drug therapy, followed by two-drug therapy, while receiving maintenance chemotherapy for AML, including thioguanine and cytarabine. Pulmonary infiltrates resolved within 2 months of treatment. However, possibly due to the bone marrow toxicity of the tuberculostatic drugs, the patient tolerated only low doses of cytostatic therapy. The boy is now 14 months off tuberculostatic treatment and 8 months off AML therapy. He is in remission of AML and tuberculosis.

Nontuberculous mycobacterial infections in Chinese hematopoietic stem cell transplantation recipients

Between 1995 and 2002, nine cases of nontuberculous mycobacterium (NTM) were isolated from 462 allogeneic stem cell transplant (SCT) recipients (1.9%), and none from 139 autologous cases. They included three cases each of Mycobacterium fortuitum and M. chelonae, and single cases of M. scrofalaceum, M. gordonnae and M. avium complex. Seven cases were respiratory, including five cases requiring treatment, and two involved infected catheters and vascular conduits. Compared with nine cases of mycobacterium tuberculosis (MTB) isolated in the same period, NTM isolation occurred later after HSCT and involved more unrelated donors. Important risk factors for NTM infection included significant aGVHD (P=0.043), leukemia relapse (P=0.022), MUD and mismatch SCT (P<0.001) and existence of BO (P<0.001). Coinfection with aspergillus was common. Invasive NTM disease required prolonged antimicrobial treatment in five cases due to M. fortuitum and M. chelonae. With better MTB prophylaxis, intensive immunosuppression and better awareness, NTM has become an emerging threat in oriental allogeneic HSCT recipients. The cutoff between colonization and infection, and the threshold for starting treatment is unclear. NTM isolation is a marker for severe immunosuppression and poor prognosis. When there is doubt over species identity or extent of infection, broad-spectrum cover may be prudent.

High rates of infection and colonization by nontuberculous mycobacteria after allogeneic hematopoietic stem cell transplantation

Nontuberculous mycobacteria (NTM) are essentially ubiquitous and can infect both immunocompetent and immunocompromised hosts. However, NTM infection is surprisingly uncommon in reports from allogeneic hematopoietic stem cell transplant (alloSCT) centers that do not routinely perform allograft T-cell depletion. We reviewed medical records for all adult patients who underwent alloSCT at our center between January 1993 and December 2001. American Thoracic Society and Centers for Disease Control and Prevention guidelines Were used to define definite, probable, and possible NTM infection. Of 571 patients, 36 of 372 (9.7%) T-cell depleted and 14 of 199 (7.0%) conventional alloSCT recipients (P=0.26) had a positive culture for NTM after alloSCT. Of the 50 patients with NTM infection, 16 had definite infection and 34 had probable or possible infection. Rates of NTM infection were 5 to 20-fold higher than rates reported by other centers. Of the 16 definite infections, nine were caused by Mycobacterium haemophilum. Two patients had disseminated M. avium complex (MAC) infection and one had a vascular catheter infected by MAC. Three patients died from complications of NTM infection. Patients with probable or possible NTM infection had markedly different epidemiology, risk factors, site and species of NTM infection, and prognosis than patients with definite NTM infection.

Neurologic complications of bone marrow transplantation

The various forms of HSCT are or will soon be accepted treatments for an ever-increasing number of hematologic and solid cancers. Attempts to reduce the mortality and morbidity of HSCT and at the same time preserve or increase its efficacy in tumor control include development of nonmyeloablative allogeneic stem-cell transplant strategies [208] and allogeneic laboratory research-enhancing graft acceptance [209,210]. Eventually, these efforts will reduce complication rates of HSCT, including neurologic complications. In the interim, the consultant neuro-oncologist or neurologist with a specific inteest in this field is faced with complex clinical syndromes, neuroradiologic imaging studies and neurophysiologic tests, and generally poorly understood pathophysiologic mechanisms. Prospective studies of HSCT patients in large transplantation centers using clinical registries are needed.

Tuberculosis in blood and marrow transplant recipients

Although one third of the world's population is infected with tuberculosis (TB), TB in blood and marrow transplant (BMT) recipients is relatively less well studied, as the incidence of TB is relatively low in developed countries with BMT units. Since the report of the first two cases in 1983, 52 cases of TB complicating BMT have been reported in the English literature from BMT centers in ten different countries. Not unexpectedly, the two largest series were reported from areas with a high incidence of TB in the general population, with about 45 cases per 10(5) inhabitants per year in Spain and about 100 cases per 10(5) inhabitants per year in Hong Kong respectively. The overall frequency of occurrence of TB in BMT recipients was 0.4% (52 cases among 13 881 BMT recipients), with a male:female ratio of 11:9 and median age of 33 (range 7-57). The incidence of TB in the general population is a major predictor of a higher frequency of occurrence in BMT recipients. Moreover, allogeneic transplantation, graft-versus-host disease, and total body irradiation were found to be risk factors associated with TB. Among the 48 cases in whom the time of manifestation were reported, only one case manifested during the neutropenic period (day 11). On the other hand, 11 cases (23%) manifest after engraftment but before day 100, and 36 (75%) manifest after day 100. The most important aspect towards making the diagnosis is a high index of suspicion, as TB occurred in relatively low frequencies especially in developed countries, and the clinical patterns usually mimic other more common infectious and non-infectious complications after BMT. As the incidence of drug resistant TB is increasing, we prefer to treat our patients for at least one year (as compared with six months in immunocompetent hosts) with four drugs in the first six months and two or three drugs for another six months. In those patients who could not tolerate oral medication, we used an intravenous regimen of rifampicin, ciprofloxacin, and amikacin until oral therapy could be instituted. The absence of relapse after termination of treatment in our patients suggested that secondary prophylaxis would not be necessary as long as immune function has been restored. With the rising incidence of TB in countries that previously enjoyed a very low prevalence of TB, attributed to the growing population of HIV-infected subjects with TB, and the changing patterns of population migration, it is important to bear a high index of suspicion of Mycobacterium tuberculosis as a pathogen in BMT recipients.

Pulmonary tuberculosis in allogeneic hematopoietic stem cell transplantation

Pulmonary tuberculosis (TB) is an endemic infectious disease in Taiwan. A retrospective study was conducted to define clinical manifestations and outcomes of patients with pulmonary TB among hematopoietic stem cell transplantation (HSCT) recipients. We identified eight out of 350 HSCT recipients as having pulmonary TB over a 6-year period. The relative risk of having pulmonary TB after HSCT was 13.1-fold higher than in the general population. There was a trend toward increased risk of having pulmonary TB in allogeneic HSCT as compared to autologous HSCT (4.8 +/- 1.8% vs 0, P = 0.067). All the eight patients with pulmonary TB received allogeneic HSCT and most (seven of eight patients) developed the infection during treatment for GVHD. Computed tomography of the chest was normal in one patient, with the rest showing either interstitial (two patients) or alveolar infiltrates (five patients) at the onset of pulmonary TB. The four fatal cases had an obviously shorter duration between HSCT and onset of infection. Our data suggest that pulmonary TB in HSCT recipients is not uncommon in this endemic area. Therefore, an effective strategy of prophylactic treatment for candidates and recipients of allogeneic HSCT, who may have latent pulmonary TB infection, must be developed.

Tuberculosis among allogeneic bone marrow transplant recipients in India

Allogeneic bone marrow transplant recipients have severe impairment of cell-mediated immunity and hence a higher incidence of mycobacterial infections might be expected in regions where tuberculosis is common. We reviewed the case records of 217 patients who underwent allogeneic bone marrow transplantation during the period 1986-1999 at our center in India. Mycobacterial infections were diagnosed in three patients (1.38%). All patients presented with extrapulmonary disease. Two patients had disseminated tuberculosis with one of these being diagnosed on autopsy studies. The third patient had tuberculosis involving the cervical lymph node and dorsal spine. Two patients treated with antituberculous therapy are well. Infection with Mycobacterium tuberculosis is not a common problem in allogeneic bone marrow recipients even in an endemic area, but when it occurs, it is usually disseminated with predominantly extrapulmonary involvement.

Fatal sepsis due to mycobacterium tuberculosis after allogeneic bone marrow transplantation

Mycobacterium tuberculosis is a serious, but rare infectious complication after allogeneic bone marrow transplantation. We describe a case of fatal sepsis due to Mycobacterium tuberculosis after allogeneic bone marrow transplantation for Philadelphia chromosome-positive ALL. The diagnosis was made after BAL. Although broad-spectrum antituberculous therapy was started immediately after diagnosis, blood cultures became positive for Mycobacterium tuberculosis. The patient developed severe pyrexias and finally died of multi-organ failure. Rapid progression of mycobacterial infection should be considered in patients post BMT with unexplained fever, particularly in patients from endemic areas.

Reconstitution of gammadelta T cell repertoire diversity after human allogeneic hematopoietic cell transplantation and the role of peripheral expansion of mature T cell population in the graft

We have examined the reconstitution of gammadelta T cell repertoire diversity after human allogeneic hematopoietic cell transplantation using a polymerase chain reaction (PCR)-based complementarity-determining region (CDR) 3 size spectratyping and DNA sequencing. The CDR3 complexity in the variable region of the T cell receptor (TCR)-delta chain was different amongst the individuals studied. Furthermore, CDR3 size distribution patterns of allogeneic hematopoietic cell transplant recipients were almost completely recovered by a few months after transplantation. In some patients, clonal predominance of the TCRDV1+ T cells became evident during the period after transplantation. In one particular donor/recipient pair, clonal predominance of TCRDV1+ T cells was already present in blood lymphocytes of the donor, and was also observed in the recipient after transplantation. Using this donor/recipient pair, we have questioned whether gammadelta T cell regeneration occurs via the peripheral expansion of mature T cells in the graft. In the donor lymphocytes, two expanding gammadelta T cell clones, which were demonstrated by CDR3 sequences of the TCR-delta chain, were recognized. These two clones were identified in the T cells from the recipient post transplant, but not before transplantation. One of the two clones was still detectable 1(1/2) years after the transplant procedure. These results strongly suggest that peripheral expansion of mature T cells in the graft is the principal pathway of gammadelta T cell regeneration after allogeneic hematopoietic cell transplantation in adults.