Acute exacerbation of Toxoplasma gondii infection after hematopoietic stem cell transplantation: five case reports among 279 recipients

Guidelines for the management of Toxoplasma gondii infection and disease in patients with haematological malignancies and after haematopoietic stem-cell transplantation: guidelines from the 9th European Conference on Infections in Leukaemia, 2022

Patients with haematological malignancies might develop life-threatening toxoplasmosis, especially after allogeneic haematopoietic stem-cell transplantation (HSCT). Reactivation of latent cysts is the primary mechanism of toxoplasmosis following HSCT; hence, patients at high risk are those who were seropositive before transplantation. The lack of trimethoprim-sulfamethoxazole prophylaxis and various immune status parameters of the patient are other associated risk factors. The mortality of toxoplasma disease-eg, with organ involvement-can be particularly high in this setting. We have developed guidelines for managing toxoplasmosis in haematology patients, through a literature review and consultation with experts. In allogeneic HSCT recipients seropositive for Toxoplasma gondii before transplant, because T gondii infection mostly precedes toxoplasma disease, we propose weekly blood screening by use of quantitative PCR (qPCR) to identify infection early as a pre-emptive strategy. As trimethoprim-sulfamethoxazole prophylaxis might fail, prophylaxis and qPCR screening should be combined. However, PCR in blood can be negative even in toxoplasma disease. The duration of prophylaxis should be a least 6 months and extended during treatment-induced immunosuppression or severe CD4 lymphopenia. If a positive qPCR test occurs, treatment with trimethoprim-sulfamethoxazole, pyrimethamine-sulfadiazine, or pyrimethamine-clindamycin should be started, and a new sample taken. If the second qPCR test is negative, clinical judgement is recommended to either continue or stop therapy and restart prophylaxis. Therapy must be continued until a minimum of two negative PCRs for infection, or for at least 6 weeks for disease. The pre-emptive approach is not indicated in seronegative HSCT recipients, after autologous transplantation, or in non-transplant haematology patients, but PCR should be performed with a high level of clinical suspicion.

Pre-Transplant Seroprevalence, Associated Factors, and Post-Transplant Incidence of Toxoplasma gondii Infection Among Heart Transplant Recipients in Japan

BACKGROUND

Among solid organ transplant (SOT) recipients, heart transplant (HT) recipients are at a higher risk of Toxoplasma gondii infection. As Toxoplasma seroprevalence varies by geographic location, updated local epidemiology is essential to guide preventive and therapeutic strategies. However, the Toxoplasma seroprevalence and incidence of post-transplant toxoplasmosis among SOT recipients in Japan are unknown.

METHODS

We performed a single-center retrospective observational study at an HT center in Tokyo, Japan. All HT recipients aged ≥18 years between 2006 and April 2019 were included. We reviewed patient charts and conducted a questionnaire survey to investigate the risk factors for infection.

RESULTS

Among 105 recipients included in the study, 11 (10.5%) were seropositive before transplant. Ninety-five recipients (90.5%), including all pre-transplant seropositive recipients, answered the questionnaire. The recipients who had lived in Okinawa (odds ratio [OR] 7.5 [95% CI 1.42-39.61]; P = .032) and who reported raw-meat eating habits (OR 4.64 [95% CI 1.04-23.3]; P = .021) were more likely to be seropositive. None of the patients developed symptoms of toxoplasmosis. The post-transplant incidence of other major adverse outcomes was not significantly different according to the pre-transplant serostatus.

CONCLUSIONS

About 10% of HT recipients at an HT center in Tokyo were seropositive for Toxoplasma pre-transplant, and none developed symptomatic toxoplasmosis post-transplant on trimethoprim-sulfamethoxazole. The history of raw meat consumption was associated with seropositivity; therefore, avoiding it might be recommended for HT recipient candidates.

Utility of plasma cell-free DNA next-generation sequencing for diagnosis of infectious diseases in patients with hematological disorders

BACKGROUND

Plasma cell-free DNA Next-Generation Sequencing has been used as a non-invasive and comprehensive method for the etiological diagnosis of infectious diseases. However, only a handful of studies have described the real-world utility of this technique in patients with hematological disorders, a cohort of patients that are distinctive due to neutropenia and weakened immune functions.

METHODS

We retrospectively analyzed the results of plasma cell-free DNA sequencing performed on 184 and 163 specimens collected from hematological patients suspected of infections with (Group I) or without (Group II) neutropenia, respectively. The diagnostic performance and the clinical impact of plasma sequencing were comparatively evaluated to conventional microbiological tests and a composite reference standard (conventional tests combined with the clinical assessment).

RESULTS

The overall positive detection rate of plasma cell-free DNA sequencing was significantly higher than that of conventional microbiological tests (72.6% vs.31.4%, P < 0.001). The positive rate of conventional microbiological tests in Group I was lower than that in Group II (25.5% vs. 38.0%, P = 0.012). Combining plasma sequencing with conventional tests yielded a positive detection rate of 75.0% and 74.8% for these two groups, respectively. Using the composite reference standard, the sensitivity and specificity of plasma sequencing were 89.1% and 65.1%, respectively. The proportions of the positive impact of cell-free DNA sequencing results in the Group I were higher than in the Group II in terms of both diagnosis and treatment (diagnosis: 54.3% vs. 40.5%, P = 0.013; treatment: 45.7% vs.30.7%, P = 0.004). A total of 73 patients (21.0%) benefited from plasma sequencing through adjustment of the antibiotic regimen.

CONCLUSIONS

The diagnostic yield of conventional microbiological tests was low in patients with neutropenia. Combining conventional tests with plasma cell-free DNA sequencing significantly improved the detection rate for pathogens and optimized antibiotic treatment. Our findings on the clinical impact warrant confirmation through larger, multicenter, randomized controlled trials. Moreover, the cost-effectiveness of this testing strategy remains unknown and requires further exploration.

Toxoplasma gondii in humans and animals in Japan: An epidemiological overview

Toxoplasmosis is a cosmopolitan protozoan zoonosis caused by Toxoplasma gondii infamous for inducing severe clinical manifestations in humans. Although the disease affects at least one billion people worldwide, it is neglected in many countries including developed ones. In literature, the epidemiological data documenting the actual incidence of the disease in humans and domestic animals from Japan are limited and importantly many earlier papers on T. gondii infections were published in Japanese and a considerable part is not available online. Herein, we review the current summary about the epidemiological situation of T. gondii infection in Japan and the potential associated risk factors in humans and animals as well as the different T. gondii genotypes isolated in Japan. Several T. gondii isolates have been identified among cats (TgCatJpTy1/k-3, TgCatJpGi1/TaJ, TgCatJpObi1 and TgCatJpOk1-4) and goats (TgGoatJpOk1-13). This literature review underscores the need for a nationwide investigation of T. gondii infection in Japanese people and assessment of the socioeconomic impact of the disease burden. Furthermore, epidemiological studies in domestic and wild animals and estimation of degree of contamination of soil or water with T. gondii oocysts are needed, for a better understanding of the scope of this public health concern.

Clinical characteristics and incidence of toxoplasmosis after autologous hematopoietic stem cell transplantation: A retrospective study and literature review

BACKGROUND

Toxoplasmosis is a rare but life-threatening infection occurring in immunocompromised hosts, including allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. However, thus far, the clinical features and incidence of toxoplasmosis in autologous HSCT (auto-HSCT) recipients remain unknown. This retrospective survey aimed to analyze 152 patients who received auto-HSCT between 1998 and 2017.

METHODS

Serological tests for Toxoplasma gondii-specific IgG were performed on 109 (71.7%) recipients, and 12 pre-HSCT recipients (11%) were Toxoplasma seropositive. Among the 12 recipients, three who did not receive trimethoprim-sulfamethoxazole (TMP/SMX) prophylaxis developed cerebral, pulmonary or disseminated toxoplasmosis due to reactivation after auto-HSCT and died despite treatment.

RESULTS

The incidences of toxoplasmosis were 2% and 25% among 152 auto-HSCT recipients (five recipients received auto-HSCT two times) and 12 pre-HSCT Toxoplasma seropositive recipients, respectively. Further, we conducted a literature review and identified 21 cases of toxoplasmosis following auto-HSCT. In these previous cases, the mortality rate was high, especially for pulmonary and disseminated toxoplasmosis. Our findings suggest that, similar to toxoplasmosis after allo-HSCT, toxoplasmosis after auto-HSCT is a fatal complication.

CONCLUSIONS

Serial screening of T. gondii-specific IgG before HSCT could contribute to the detection of Toxoplasma reactivation and allow for prompt diagnosis and treatment. The present study is the first to reveal the incidence of toxoplasmosis after auto-HSCT among seropositive patients in Japan.

Toxoplasmosis after allogeneic hematopoietic stem cell transplantation: Impact of serostatus-based management

Toxoplasmosis caused by Toxoplasma gondii (T. gondii) is a serious infectious complication after allogeneic hematopoietic stem cell transplantation (HSCT). The incidence of toxoplasmosis varies widely because of the variabilities of seroprevalence among patient populations. The incidence and the optimal management of toxoplasmosis after allogeneic HSCT in a patient population with a low seroprevalence have not been fully evaluated. We conducted a single-center retrospective study evaluating toxoplasmosis in Japanese patients who underwent allogeneic HSCT. Of the 728 evaluable patients, only 5 developed toxoplasmosis with a median onset of day 60 post-transplant (range, day 55-393). The cumulative incidence was 0.7% (95% CI: 0.3%-1.5%) at day 500 post-transplant. Four of the five patients succumbed due to toxoplasmosis. The more recently treated 220 patients (not the earlier 508 patients) were screened for the T. gondii serostatus, and prophylactic treatment with trimethoprim/sulfamethoxazole was applied. All five patients with toxoplasmosis were in the unscreened group, and there was no case of toxoplasmosis after the introduction of the screening and prophylactic treatment. Our results suggest that toxoplasmosis after allogeneic HST is rare but can develop as a life-threatening complication even in the populations with low seroprevalence, and that prophylactic treatment for seropositive patients could effectively prevent toxoplasmosis.

Toxoplasmosis after allogeneic haematopoietic cell transplantation-disease burden and approaches to diagnosis, prevention and management in adults and children

BACKGROUND

Toxoplasmosis is a rare but highly lethal opportunistic infection after allogeneic haematopoietic cell transplantation (HCT). Successful management depends on screening, early recognition and effective treatment.

OBJECTIVES

To review the current epidemiology and approaches to diagnosis, prevention and treatment of toxoplasmosis in adult and paediatric allogeneic HCT recipients.

SOURCE

Search of the English literature published in MEDLINE up to 30 June 2020 using combinations of broad search terms including toxoplasmosis, transplantation, diagnosis, epidemiology, prevention and treatment. Selection of articles for review and synthesis on the basis of perceived quality and relevance of content.

CONTENT

Toxoplasmosis continues to be a major challenge in the management of allogeneic HCT recipients. Here we provide a summary of published case series of toxoplasmosis in adult and paediatric patients post allogeneic HCT. We review and discuss the pathogenesis, epidemiology, clinical presentation, diagnosis and current recommendations for prevention and treatment. We also discuss impacts of toxoplasmosis in this setting and factors affecting outcome, emphasizing attention to neurological, neuropsychological and neurocognitive late effects in survivors.

IMPLICATIONS

Apart from careful adherence to established strategies of disease prevention through avoidance of primary infection, identification of seropositive patients and implementation of molecular monitoring, future perspectives to improve the control of toxoplasmosis in allogeneic HCT recipients may include the systematic investigation of pre-emptive treatment, development of immunomodulatory approaches, antimicrobial agents with activity against the cyst form and vaccines to prevent chronic infection.

Toxoplasmosis in Transplant Recipients, Europe, 2010-2014

Transplantation activity is increasing, leading to a growing number of patients at risk for toxoplasmosis. We reviewed toxoplasmosis prevention practices, prevalence, and outcomes for hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT; heart, kidney, or liver) patients in Europe. We collected electronic data on the transplant population and prevention guidelines/regulations and clinical data on toxoplasmosis cases diagnosed during 2010–2014. Serologic pretransplant screening of allo-hematopoietic stem cell donors was performed in 80% of countries, screening of organ donors in 100%. SOT recipients were systematically screened in 6 countries. Targeted anti-Toxoplasma chemoprophylaxis was heterogeneous. A total of 87 toxoplasmosis cases were recorded (58 allo-HSCTs, 29 SOTs). The 6-month survival rate was lower among Toxoplasma-seropositive recipients and among allo-hematopoietic stem cell and liver recipients. Chemoprophylaxis improved outcomes for SOT recipients. Toxoplasmosis remains associated with high mortality rates among transplant recipients. Guidelines are urgently needed to standardize prophylactic regimens and optimize patient management.

Non-GVHD ocular complications after hematopoietic cell transplantation: expert review from the Late Effects and Quality of Life Working Committee of the CIBMTR and Transplant Complications Working Party of the EBMT

Non-graft-versus-host disease (non-GVHD) ocular complications are generally uncommon after hematopoietic cell transplantation (HCT), but can cause prolonged morbidity affecting activities of daily living and quality of life. Here we provide an expert review of non-GVHD ocular complications in a collaboration between transplant physicians and ophthalmologists through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. Complications discussed in this review include cataracts, glaucoma, ocular infections, ocular involvement with malignancy, ischemic microvascular retinopathy, central retinal vein occlusion, retinal hemorrhage, retinal detachment and ocular toxicities associated with medications. We have summarized incidence, risk factors, screening, prevention and treatment of individual complications and generated evidence-based recommendations. Baseline ocular evaluation before HCT should be considered in all patients who undergo HCT. Follow-up evaluations should be considered according to clinical symptoms, signs and risk factors. Better preventive strategies and treatments remain to be investigated for individual ocular complications after HCT. Both transplant physicians and ophthalmologists should be knowledgeable of non-GVHD ocular complications and provide comprehensive collaborative team care.

Toxoplasma Encephalitis following Tandem Autologous Hematopoietic Stem Cell Transplantation: A Case Report and Review of the Literature

Infection with Toxoplasma gondii is a rare but often fatal complication in hematopoietic stem cell transplantation (HSCT) recipients. Most cases have been reported in allogeneic (allo-) HSCT recipients, with only narrative reports following autologous HSCT (ASCT). We report the case of a 58-year-old Caucasian male presenting with toxoplasma encephalitis following tandem ASCT for myeloma and successfully treated with diagnosis by polymerase chain reaction analysis of cerebrospinal fluid. He was treated with sulfadiazine and pyrimethamine (with leucovorin) followed by pyrimethamine and atovaquone as secondary prophylaxis while receiving subsequent therapy for progressive multiple myeloma. Toxoplasmosis is a potential complication in allo-HSCT as well as ASCT recipients and should be considered in any post-HSCT patient with neurological dysfunction. Rapid diagnosis and immediate antimicrobial treatment are essential to avoid morbidity and mortality.

Non-Graft-versus-Host Disease Ocular Complications after Hematopoietic Cell Transplantation: Expert Review from the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society for Blood and Marrow Transplantation

Non-graft-versus-host disease (GVHD) ocular complications are generally uncommon after hematopoietic cell transplantation (HCT) but can cause prolonged morbidity affecting activities of daily living and quality of life. Here we provide an expert review of non-GVHD ocular complications in a collaboration between transplantation physicians and ophthalmologists through the Late Effects and Quality of Life Working Committee of the Center for International Blood and Marrow Transplant Research and the Transplant Complications Working Party of the European Society of Blood and Marrow Transplantation. Complications discussed in this review include cataracts, glaucoma, ocular infections, ocular involvement with malignancy, ischemic microvascular retinopathy, central retinal vein occlusion, retinal hemorrhage, retinal detachment and ocular toxicities associated with medications. We summarize the incidence, risk factors, screening, prevention, and treatment of individual complications and generate evidence-based recommendations. Baseline ocular evaluation before HCT should be considered in all patients who undergo HCT. Follow-up evaluations should be considered according to clinical signs and symptoms and risk factors. Better preventive strategies and treatments remain to be investigated for individual ocular complications after HCT. Both transplantation physicians and ophthalmologists should be knowledgeable about non-GVHD ocular complications and provide comprehensive collaborative team care.

Treatment of Toxoplasmosis: Historical Perspective, Animal Models, and Current Clinical Practice

Primary Toxoplasma gondii infection is usually subclinical, but cervical lymphadenopathy or ocular disease can be present in some patients. Active infection is characterized by tachyzoites, while tissue cysts characterize latent disease. Infection in the fetus and in immunocompromised patients can cause devastating disease. The combination of pyrimethamine and sulfadiazine (pyr-sulf), targeting the active stage of the infection, is the current gold standard for treating toxoplasmosis, but failure rates remain significant. Although other regimens are available, including pyrimethamine in combination with clindamycin, atovaquone, clarithromycin, or azithromycin or monotherapy with trimethoprim-sulfamethoxazole (TMP-SMX) or atovaquone, none have been found to be superior to pyr-sulf, and no regimen is active against the latent stage of the infection. Furthermore, the efficacy of these regimens against ocular disease remains uncertain. In multiple studies, systematic screening for Toxoplasma infection during gestation, followed by treatment with spiramycin for acute maternal infections and with pyr-sulf for those with established fetal infection, has been shown to be effective at preventing vertical transmission and minimizing the severity of congenital toxoplasmosis (CT). Despite significant progress in treating human disease, there is a strong impetus to develop novel therapeutics for both the acute and latent forms of the infection. Here we present an overview of toxoplasmosis treatment in humans and in animal models. Additional research is needed to identify novel drugs by use of innovative high-throughput screening technologies and to improve experimental models to reflect human disease. Such advances will pave the way for lead candidates to be tested in thoroughly designed clinical trials in defined patient populations.

Parasitic Infections Associated with Unfavourable Outcomes in Transplant Recipients

Introduction. The immunosuppression used after transplantation (Tx) is associated with an increased risk of opportunistic infections. In Europe, parasitic infections after Tx are much less common than viral, bacterial and fungal ones. However, diseases caused by parasites are very common in tropical countries. In the last years the number of travellers with immunosuppression visiting tropical countries has increased. Methods. We performed a literature review to evaluate a risk of parasitic infections after Tx in Europe. Results. There is a real risk of parasitic infection in patients after Tx travelling to tropical countries. Malaria, leishmaniasis, strongyloidiasis and schistosomiasis are the most dangerous and relatively common. Although the incidence of these tropical infections after Tx has not increased, the course of disease could be fatal. There are also some cosmopolitan parasitic infections dangerous for patients after Tx. The greatest threat in Europe is toxoplasmosis, especially in heart and bone marrow recipients. The most severe manifestations of toxoplasmosis are myocarditis, encephalitis and disseminated disease. Diarrhoea is one of the most common symptoms of parasitic infection. In Europe the most prevalent pathogens causing diarrhoea are Giardia duodenalis and Cryptosporidium. Conclusions. Solid organ and bone marrow transplantations, blood transfusions and immunosuppressive treatment are associated with a small but real risk of parasitic infections in European citizens. In patients with severe parasitic infection, i.e., those with lung or brain involvement or a disseminated disease, the progression is very rapid and the prognosis is bad. Establishing a diagnosis before the patient's death is challenging.

Diagnostic Value of Positive Findings of Toxoplasma gondii-Specific Immunoglobulin M Serum Antibody in Uveitis Patients to Confirm Ocular Toxoplasmosis

Purpose: To assess the value of positive immunoglobulin (Ig) M serum antibody (Ab) findings in uveitis patients. Methods: We reviewed medical records of patients who had a positive serological test for Toxoplasma gondii-specific IgM Ab. Their clinical data, including history, demographic characteristics, laboratory findings, clinical findings, treatment outcomes, and recurrences, were reviewed retrospectively. Results: Of 2919 uveitis patients who underwent a serological test for suspected ocular toxoplasmosis (OT), 18 presented with positive Ig M results. All 18 patients (100.0% specificity) were clinically diagnosed with OT. None had any retinochoroidal scar at the initial visit, indicating the OT was a recent and primary infection. However, 15 patients (83.3%) had no history suspected to account for the Toxoplasma transmission. Conclusions: The T. gondii IgM serum Ab is a specific biomarker for diagnosis of primary OT. Epidemiological studies are warranted to investigate the non-classic transmission routes of T. gondii in OT.

An unexpected but underestimated case of disseminated toxoplasmosis

Toxoplasma gondii is a ubiquitous intracellular parasite that can cause disseminated infection following reactivation in immunocompromised hosts. We describe a 58-year-old man who died of refractory shock because of disseminated toxoplasmosis. The diagnosis was only made postmortem on autopsy. We discuss the importance of considering toxoplasmosis on the differential diagnosis in high-risk patients, and review the role of screening and chemoprophylaxis in preventing infection.

Allogeneic hematopoietic stem cell transplant recipients and parasitic diseases: A review of the literature of clinical cases and perspectives to screen and follow-up active and latent chronic infections

BACKGROUND

Allogeneic hematopoietic stem cell transplant (HSCT) recipients are at substantial risk for a variety of infections depending upon numerous factors, such as degree of immunosuppression, host factors, and period after transplantation. Bacterial, fungal, viral, as well as parasitic infections can occur with high morbidity and mortality.

OBJECTIVES

The aim of this study was to evaluate the magnitude of the occurrence of parasitic infections in allogeneic HSCT recipients. Modalities of transmission, methods of diagnosis, treatment, donor and recipient pre-transplant screening and prevention measures of the most serious parasitic infections have also been discussed.

MATERIALS AND METHODS

We systematically reviewed literature records on post-transplant (allogeneic HSCT) parasitic infections, identified through PubMed database searching, using no language or time restrictions. Search was concluded on December 31, 2015. In the present review, we only discussed post-transplant parasitic infections in allogeneic HSCT. Only exclusion criteria were absence of sufficient information on the transmission of parasitic infection to the recipient. Autologous HSCT recipients have not been included because of the absence of a proper allogeneic transplantation even in presence of blood or blood product transfusions. The methods and findings of the present review have been reported based on the preferred reporting items for systematic reviews and meta-analysis checklist (PRISMA).

RESULTS

Regarding allogeneic HSCT recipients, from data published in the literature the real burden of parasitic infections cannot be really estimated. Nevertheless, a positive trend on publication number exists, probably because of more than one reason: (i) the increasing number of patients transplanted and then treated with immunosuppressive agents, (ii) the "population shift" resulting from immigration and travels to endemic areas, and (iii) the increasing of attention for diagnosis/notification/publication of cases.

CONCLUSIONS

Considering parasitic infections as emerging and potentially serious in their evolution, additional strategies for the prevention, careful screening and follow-up, with a high level of suspicion, identification, and preemptive therapy are necessary in transplant recipients.

PERSPECTIVES

The Authors' viewpoint in the perspective to screen and follow-up active and latent chronic parasitosis in stem cells donors and recipients: a proposal for a flow chart.

Clinical characteristics and computed tomography findings of pulmonary toxoplasmosis after hematopoietic stem cell transplantation

The prognosis of pulmonary toxoplasmosis, including disseminated toxoplasmosis involving the lungs, following hematopoietic stem cell transplantation (HSCT) is extremely poor due to the difficulties associated with early diagnosis and the rapidly progressive deterioration of multiorgan function. In our institution, we identified nine cases of toxoplasmosis, representing incidences of 2.2 and 19.6 % among all HSCT recipients and seropositive HSCT recipients, respectively. Of the patients with toxoplasmosis, six had pulmonary toxoplasmosis. Chest computed tomography (CT) findings revealed centrilobular, patchy ground-glass opacities (n = 3), diffuse ground-glass opacities (n = 2), ground-glass opacities with septal thickening (n = 1), and marked pleural effusion (n = 1). All cases died, except for one with suspected pulmonary toxoplasmosis who was diagnosed by a polymerase chain reaction assay 2 days after the onset of symptoms. In pulmonary toxoplasmosis, CT findings are non-specific and may mimic pulmonary congestion, atypical pneumonia, viral pneumonitis, and bronchopneumonia. Early diagnosis and treatment is crucial for overcoming this serious infectious complication. Pulmonary toxoplasmosis should be considered during differential diagnosis in a recipient with otherwise unexplained signs of infection and CT findings with ground-glass opacities, regardless of the distribution.

Toxoplasma prophylaxis in haematopoietic cell transplant recipients: a review of the literature and recommendations

PURPOSE OF REVIEW

Toxoplasmosis in haematopoietic cell transplant (HCT) recipients is associated with high morbidity and mortality rates. Prophylaxis following HCT is recommended for high-risk pre-HCT toxoplasma-seropositive (pre-HCTSP) recipients. However, there is no agreement or consistency among programmes on whether to adopt prophylaxis or not, or if used, on the chosen antitoxoplasma prophylactic regimen. This review discusses the role of prophylaxis, and preemptive treatment, for toxoplasmosis in the setting of HCT.

RECENT FINDINGS

Approximately two-thirds of toxoplasmosis cases following HCT are reported in allogeneic pre-HCTSP (allo pre-HCTSP) patients. This finding confirms a major role of reactivation of latent infection in the pathogenesis of toxoplasmosis in this patient population. Toxoplasma disease-related mortality in allo pre-HCTSP patients was reported at 62%, but it can be significantly decreased with early detection and treatment of toxoplasma infection. There are no randomized trials comparing the efficacy of different prophylactic agents to prevent toxoplasmosis after HCT. Several observational studies have demonstrated the efficacy of trimethoprim-sulfamethoxazole (TMP/SMX) in decreasing the incidence of toxoplasmosis following HCT. There is limited information regarding efficacy of other prophylactic agents. Preemptive treatment using routine blood PCR monitoring seems to be beneficial in detecting infection early and preventing disease in several observational studies and has been adopted for allo pre-HCTSP HCT patients when universal prophylaxis is not possible.

SUMMARY

Universal prophylaxis with TMP/SMX in allo pre-HCTSP patients should be implemented by all transplant programmes. Preemptive treatment with routine blood PCR monitoring is an option if prophylaxis cannot be used.

Pulmonary toxoplasmosis in immunocompromised patients with interstitial pneumonia: a single-centre prospective study assessing PCR-based diagnosis

AIMS

Pulmonary toxoplasmosis has become a very rare parasitic infection since the advent of highly active antiretroviral therapies. It is generally diagnosed by the direct microscopic observation of Toxoplasma gondii tachyzoites in bronchoalveolar lavage fluid (BALF). The aim of this study was to assess possible improvements in diagnostic performance associated with the use of real-time PCR.

METHODS

This prospective study was carried out on BALFs obtained from immunocompromised patients over a 2-year period. We systematically compared the results of conventional staining with those of molecular detection.

RESULTS

Two cases of pulmonary toxoplasmosis were diagnosed for a total of 336 samples. PCR did not detect any additional cases and was more time-consuming than conventional staining.

CONCLUSIONS

Conventional staining is a reliable technique and is probably the most appropriate method for experienced microbiology laboratories, whereas T. gondii-specific PCR may be useful for laboratories with less experience in parasitology.

TRIAL REGISTRATION NUMBER

2015_030, May 27th 2015.

Toxoplasmic Encephalitis with Untreated Hairy Cell Leukemia Variant

Toxoplasmic encephalitis is a rare infectious complication in patients with hematological malignancy except for allogeneic hematopoietic stem cell transplantation (HSCT). We herein report a case of possible toxoplasmic encephalitis with untreated hairy cell leukemia variant. Magnetic resonance imaging showed multiple nodules with surrounding edema in the entire cerebrum. A polymerase chain reaction analysis for Toxoplasma gondii was negative. Her signs and symptoms fully recovered by empirical therapy with sulfadiazine and pyrimethamine. Toxoplasmic encephalitis may occur in patients who undergo non-allogeneic HSCT for hematological malignancies, even in those who have not been treated.

Role of bronchoalveolar lavage in the diagnosis of pulmonary infiltrates in immunocompromised patients

PURPOSE OF REVIEW

To describe the role of bronchoalveolar lavage (BAL) in the evaluation of pulmonary disease in immunocompromised patients.

RECENT FINDINGS

Recent discoveries in this field are largely in two areas: the array of diagnostic testing performed on BAL fluid and technical details that can enhance the yield from this procedure. Regarding diagnostic testing, the addition of new assays, including Aspergillus galactomannan antigen assay, respiratory viral panels, and Pneumocystis jirovecii PCR, has improved the diagnostic yield of BAL over conventional cultures and stains. To improve the diagnostic yield of the procedure itself, it should be done early in the clinical course, with the BAL in the anatomic area most affected, and with a preprocedural computed tomography of the chest to properly plan the procedure.

SUMMARY

Bronchoscopic evaluation with BAL can provide important diagnostic information in immunocompromised patients with pulmonary diseases and should be routinely performed when clinically indicated and able to be completed safely.

Successful treatment of toxoplasmic encephalitis diagnosed early by polymerase chain reaction after allogeneic hematopoietic stem cell transplantation: two case reports and review of the literature

Toxoplasmic encephalitis represents a rare, but often fatal infection after allogeneic hematopoietic stem cell transplantation. Polymerase chain reaction (PCR)-based preemptive therapy is considered promising for this disease, but is not routinely applied, especially in low seroprevalence countries including Japan. We encountered 2 cases of toxoplasmic encephalitis after transplantation that were successfully treated. The diagnosis of toxoplasmic encephalitis in these cases was confirmed by PCR testing when neurological symptoms were observed. Both patients received pyrimethamine and sulfadiazine treatments within 2 weeks of the development of neurological symptoms, and remained free of recurrence for 32 and 12 months. These results emphasized the importance of the PCR test and immediate treatment after diagnosis for the management of toxoplasmic encephalitis.