Immune Dysfunction and Infection - Interaction between CLL and Treatment: A Reflection on Current Treatment Paradigms and Unmet Needs.

BACKGROUND: Chronic lymphocytic leukemia (CLL) is a hematological malignancy characterized by immune dysfunction, which significantly contributes to increased morbidity and mortality due to infections. SUMMARY: Advancement in therapeutic strategies based on combination chemoimmunotherapy and targeted treatment have increased life expectancy for patients affected by CLL. However, mortality and morbidity due to infection showed no improvement over the last decades. Although therapy options are highly efficient in targeting leukemic cells, several studies highlighted the interactions of different treatments with the tumor microenvironment immune components, significantly impacting their clinical efficacy and fostering increased risk of infections. KEY MESSAGES: Given the profound immune dysfunction caused by CLL itself, treatment can thus represent a double-edged sword. Thus, it is essential to increase our understanding and awareness on how conventional therapies affect the disease-microenvironment-infection axis to ensure the best personalized strategy for each patient. This requires careful consideration of the advantages and disadvantages of efficient treatments, whether chemoimmunotherapy or targeted combinations, leading to risk of infectious complications. To this regard, our machine learning-based algorithm CLL Treatment-Infection Model, currently implemented into the local electronic health record system for Eastern Denmark, aims at early identification of patients at high risk of serious infections (PreVent-ACaLL; NCT03868722). We here review strategies for management of immune dysfunction and infections in CLL.

Preemptive high-flow nasal cannula treatment in severe bronchiolitis: Results from a high-volume, resource-limited pediatric emergency department.

BACKGROUND: The aims of this study were to evaluate the outcomes of patients with severe bronchiolitis who received preemptive high-flow nasal cannula (HFNC) treatment according to the authors' protocol, and to identify potential baseline characteristics that might predict patients who will not benefit from HFNC. METHODS: This was a retrospective chart review of patients with severe bronchiolitis, who received preemptive HFNC treatment according to the authors' protocol and who were admitted to the pediatric emergency department between January 1, 2015, and December 31, 2016. RESULTS: Eighty-four patients in total were enrolled over the 2 year period. Twenty-three patients (27.3%) failed HFNC. Of these, four responded to non-invasive mechanical ventilation and 19 required subsequent invasive ventilation. According to logistic regression analysis, existence of a chronic condition, significant tachycardia, existence of dehydration, and a venous pH <7.30 at admission were found to be predictors of HFNC failure. There were no cases of pneumothorax or any other reported adverse effects related to HFNC therapy. CONCLUSIONS: Preemptive HFNC treatment, complying with a preestablished protocol, might be a safe way to support patients with severe bronchiolitis in high-volume, resource-limited pediatric emergency departments. The existence of a chronic condition, significant tachycardia, dehydration, and a venous pH <7.30 at admission could be risk factors for preemptive HFNC treatment failure in severe bronchiolitis.

Preemptive immunosuppressive treatment for asymptomatic serological reactivation may reduce renal flares in patients with lupus nephritis: a cohort study.

BACKGROUND: Serological activity may precede clinical flares of lupus nephritis (LN) but the management of asymptomatic serological reactivation (ASR) remains undefined. METHODS: We conducted a retrospective analysis of 138 episodes of ASR, which included 53 episodes in which immunosuppression was increased preemptively and 85 episodes in which treatment was unaltered. Preemptive immunosuppressive treatment comprised increasing the dose of prednisolone to ∼0.5 mg/kg/day, and in patients already on mycophenolate mofetil (MMF) or azathioprine (AZA), increasing the dose to 1.5 g/day and 100 mg/day, respectively. RESULTS: Thirty-four episodes of renal flare occurred during follow-up (88.8 ± 77.3 and 82.8 ± 89.7 months in the preemptive group and controls, respectively), following 5 (9.4%) of preemptively treated ASR and 27 (31.8%) of untreated ASR [hazard ratio 0.3 (confidence interval 0.1-0.7), P = 0.012]. Preemptive treatment was associated with superior survival free of renal relapse (99, 92 and 90% at 6, 12 and 24 month, respectively, compared with 94, 69 and 64% in controls; P = 0.011), whereas survival rate free of extrarenal relapse was similar in the two groups. Preemptively treated patients who did not develop renal flares showed better renal function preservation (estimated glomerular filtration rate slope +0.54 ± 0.43 mL/min/1.73 m2/year, compared with -2.11 ± 0.50 and -1.00 ± 0.33 mL/min/1.73 m2/year, respectively, in controls who did and did not develop subsequent renal flares; P = 0.001 and 0.012, respectively). Preemptive treatment was associated with an increased incidence of gastrointestinal side effects attributed to MMF (P = 0.031), whereas infection rate did not differ between the two groups. CONCLUSION: A preemptive moderate increase of immunosuppression for ASR in LN patients may reduce renal flares and confer benefit to long-term renal function.

Failure of primary atovaquone prophylaxis for prevention of toxoplasmosis in hematopoietic cell transplant recipients.

The efficacy of primary prophylaxis with atovaquone in preventing Toxoplasma reactivation and disease in hematopoietic cell transplant (HCT) recipients is unknown. We describe 2 cases of atovaquone prophylaxis failure in pre-HCT Toxoplasma-seropositive (pre-HCTSP) recipients who underwent allogeneic HCT (allo-HCT) and review the literature on atovaquone prophylaxis in HCT recipients.

The kinetics of relapse in DEK-NUP214-positive acute myeloid leukemia patients.

Preemptive treatment of relapse of acute myeloid leukemia (AML) holds the promise to improve the prognosis of this currently highly lethal condition. Proposed treatment modalities applicable in preemptive cytoreduction (e.g., demethylating agents or standard chemotherapy) differ substantially in interval from administration to antileukemic effect. The t(6;9) balanced translocation, producing the DEK-NUP214 fusion protein, is seen in only 1% of patients with AML. We hypothesized that in these patients, who relapse with a very high frequency, a more detailed knowledge of leukemic relapse growth kinetics would improve the personalized decision-making regarding re-administration of chemotherapy. Based on standardized quantitative PCR data, we therefore delineated the relapse kinetics in a cohort of 27 relapsing DEK-NUP214-positive patients treated in four different European countries. The prerelapse leukemic burden increased with a median doubling time of 13 d (range: 5-51 d, median: 0.71 logs/month, range: 0.18-1.91 logs/month), with FLT3-ITD-positive patients relapsing significantly faster than FLT3-ITD-negative ones (median: 0.9 vs. 0.6 logs/month, Wilcoxon rank sum test, P = 0.041). Peripheral blood and bone marrow were equally useful for minimal residual disease (MRD) detection, and thus, we found that with sampling intervals of 2 months, 94% of relapses would be detected with a median time from MRD detection to hematological relapse of 64 d. In conclusion, this data provide algorithms for handling the rare patients with DEK-NUP214-positive AML allowing for planning of both MRD follow-up and, upon molecular relapse, the timing of cytoreduction or possibly transplant procedures.

Assessing the impact of positive cultures in preservation fluid on renal transplant outcomes: a scoping review.

BACKGROUND: Infection following kidney transplantation is a significant risk factor for adverse outcomes. While the donor may be a source of infection, microbiological assessment of the preservation fluid (PF) can mitigate potential recipient contamination and help curb unnecessary antibiotic use. This scoping review aimed to describe the available literature on the association between culture-positive preservation fluid, its clinically relevant outcomes, and management. METHODS: Following the Joanna Briggs Institute's scoping review recommendations, a comprehensive search in databases (EMBASE, MEDLINE, and gray literature) was conducted, with data independently extracted by two researchers from selected studies. RESULTS: We analysed 24 articles involving 12,052 samples, predominantly published post-2000, 91% of which retrospective. The prevalence of culture-positive preservation fluid varied from 0.86 to 77.8%. Coagulase-negative staphylococci emerged as the most frequently isolated pathogen in 14 studies. The presence of ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species), observed in two studies involving 1074 donors, was significantly associated with an increased risk of probable donor-derived infections (p-DDI). Of the reviewed articles, 14 reported on probable donor-derived infections, while 19 addressed the topic of preemptive antibiotic therapy. CONCLUSIONS: Routine culturing of preservation fluid is crucial for the identification of pathogenic organisms, facilitates targeted treatment and prevents probable donor-derived infections. Furthermore, this approach helps avoid the treatment of low-virulence contaminants, thereby reducing unnecessary antimicrobial use and the risk of antibiotic resistance. In cases where ESKAPE or Candida species are detected, preemptive therapy appears to be an important strategy. Given that the current evidence primarily stems from retrospective studies, there is a pressing need for large-scale, prospective trials to corroborate these recommendations. This scoping review currently represents the most thorough compilation of evidence on how contamination of preservation fluids affects kidney transplant management.

A new era in the management of spinal metastasis.

Despite the recent advances in cancer treatment, the incidence of patients with spinal metastases continues to grow along with the total number of cancer patients. Spinal metastases can significantly impair activities of daily living (ADL) and quality of life (QOL), compared with other types of bone metastases, as they are characterized with severe pain and paralysis caused by skeletal-related events. Reduced ADL can also lead to treatment limitations as certain anticancer agents and radiation therapy are not compatible treatments; thus, leading to a shorter life expectancy. Consequently, maintaining ADLs in patients with spinal metastases is paramount, and spine surgeons have an integral role to play in this regard. However, neurosurgeon, orthopedic and spinal surgeons in Japan do not have a proactive treatment approach to spinal metastases, which may prevent them from providing appropriate treatment when needed (clinical inertia). To overcome such endemic inertia, it is essential for 1) spine surgeons to understand and be more actively involved with patients with musculoskeletal disorders (cancer locomo) and cancer patients; 2) the adoption of a multidisciplinary approach (coordination and meetings not only with the attending oncologist but also with spine surgeons, radiologists, rehabilitation specialists, and other professionals) to preemptive treatment such as medication, radiotherapy, and surgical treatment; and 3) the integration of the latest findings associated with minimally invasive spinal treatments that have expanded the indications for treatment of spinal metastases and improved treatment outcomes. This heralds a new era in the management of spinal metastases.

SOHO State of the Art Updates and Next Questions | Infections in Chronic Lymphocytic Leukemia Patients: Risks and Management.

Although chronic lymphocytic leukemia (CLL) is a malignancy characterized by accumulation of tumor cells in the blood, bone marrow, lymph nodes and secondary lymphoid tissues, the hallmark of the disease and the major cause of death for patients with CLL is actually immune dysfunction and associated infections. Despite improvement in treatment based on combination chemoimmunotherapy and targeted treatment with BTK and BCL-2 inhibitors leading to longer overall survival for patients with CLL, the mortality due to infections have not improved over the last 4 decades. Thus, infections are now the main cause of death for patients with CLL, posing threats to the patient whether during the premalignant state of monoclonal B lymphocytosis (MBL), during the watch & wait phase for treatment naïve patients, or upon treatment in terms of chemoimmunotherapy or targeted treatment. To test whether the natural history of immune dysfunction and infections in CLL can be changed, we have developed the machine learning based algorithm CLL-TIM.org to identify these patients. The CLL-TIM algorithm is currently being used for selection of patients for the clinical trial PreVent-ACaLL (NCT03868722), testing whether short-term treatment with the BTK inhibitor acalabrutinib and the BCL-2 inhibitor venetoclax can improve immune function and decrease the risk of infections for this high-risk patient population. We here review the background for and management of infectious risks in CLL.

Once-Daily Foscarnet Is Effective for Human Herpesvirus 6 Reactivation after Hematopoietic Stem Cell Transplantation.

Human herpesvirus 6 (HHV-6) reactivation is common after allogeneic hematopoietic stem cell transplantation (allo-HSCT) and is associated with higher mortality and increased transplantation-related complications. We hypothesized that preemptive treatment with a short course of foscarnet at a lower cutpoint of plasma HHV-6 viral load would be effective in treating early HHV-6 reactivation, preventing complications and precluding hospitalization of these patients. We reviewed outcomes of adult patients (age ≥18 years) who received preemptive treatment with once-daily foscarnet 60 to 90 mg/kg for 7 days for HHV-6 reactivation after allo-HSCT at our institution between May 2020 and November 2022. Plasma HHV-6 viral load was monitored by quantitative PCR twice monthly in the first 100 days post-transplantation and twice weekly after reactivation until resolution. Eleven patients with a median age of 46 years (range, 23 to 73 years) were included in the analysis. HSCT was performed with a haploidentical donor in 10 patients and with an HLA-matched related donor in 1 patient. The most common diagnosis was acute leukemia (9 patients). Myeloablative and reduced-intensity conditioning regimens were used in 4 and 7 patients, respectively. Ten of the 11 patients received post-transplantation cyclophosphamide-based graft-versus-host disease prophylaxis. The median follow-up was 440 days (range, 174 to 831 days), and the median time to HHV-6 reactivation was 22 days post-transplantation (range, 15 to 89 days). The median viral load at first reactivation was 3,100 copies/mL (range, 210 to 118,000 copies/mL), and the median peak viral load was 11,300 copies/mL (range, 600 to 983,000 copies/mL). All patients received a short course of foscarnet at either 90 mg/kg/day (n = 7) or 60 mg/kg/day (n = 4). In all patients, plasma HHV-6 DNA was undetectable at completion of 1 week of treatment. No HHV-6 encephalitis or pneumonitis occurred. All patients achieved neutrophil and platelet engraftment after a median of 16 days (range, 8 to 22 days) and 26 days (range, 14 to 168 days), respectively, with no secondary graft failure. No complications related to foscarnet administration were noted. One patient with very high HHV-6 viremia had recurrent reactivation and received a second course of foscarnet as an outpatient. A short course of once-daily foscarnet is effective in treating early HHV-6 reactivation post-transplantation and may reduce the incidence of HHV-6-related and treatment-related complications and preclude hospitalization in these patients.

Prevention of viral infections in solid organ transplant recipients in the era of COVID-19: a narrative review.

INTRODUCTION: In solid organ transplant (SOT) recipients, viral infections are associated with direct morbidity and mortality and may influence long-term allograft outcomes. Prevention of viral infections by vaccination, antiviral prophylaxis, and behavioral measures is therefore of paramount importance. AREAS COVERED: We searched Pubmed to select publications to review current preventive strategies against the most important viral infections in SOT recipients, including SARS-CoV-2, influenza, CMV, and other herpesvirus, viral hepatitis, measles, mumps, rubella, and BK virus. EXPERT OPINION: The clinical significance of the reduced humoral response following mRNA SARS-CoV-2 vaccines in SOT recipients still needs to be better clarified, in particular with regard to the vaccines' efficacy in preventing severe disease. Although a third dose improves immunogenicity and is already integrated into routine practice in several countries, further research is still needed to explore additional interventions. In the upcoming years, further data are expected to better delineate the role of virus-specific cell mediated immune monitoring for the prevention of CMV and potentially other viral diseases, and the role of the letermovir in the prevention of CMV in SOT recipients. Future studies including clinical endpoints will hopefully facilitate the integration of successful new influenza vaccination strategies into clinical practice.

Case Report: Preemptive Treatment With Low-Dose PD-1 Blockade and Azacitidine for Molecular Relapsed Acute Myeloid Leukemia With RUNX1-RUNX1T1 After Allogeneic Hematopoietic Stem Cell Transplantation.

Acute myeloid leukemia (AML) patients who develop hematological relapse (HR) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) generally have dismal clinical outcomes. Measurable residual disease (MRD)-directed preemptive interventions are effective approaches to prevent disease progression and improve prognosis for molecular relapsed patients with warning signs of impending HR. In this situation, boosting the graft-vs-leukemia (GVL) effect with immune checkpoint inhibitors (ICIs) might be a promising prevention strategy, despite the potential for causing severe graft-vs-host disease (GVHD). In the present study, we reported for the first time an AML patient with RUNX1-RUNX1T1 who underwent preemptive treatment with the combined application of tislelizumab (an anti-PD-1 antibody) and azacitidine to avoid HR following allo-HSCT. On day +81, molecular relapse with MRD depicted by RUNX1-RUN1T1-positivity as well as mixed donor chimerism occurred in the patient. On day +95, with no signs of GVHD and an excellent eastern cooperative oncology group performance status (ECOG PS), the patient thus was administered with 100 mg of tislelizumab on day 1 and 100 mg of azacitidine on days 1-7. After the combination therapy, complete remission was successfully achieved with significant improvement in hematologic response, and the MRD marker RUNX1-RUNX1T1 turned negative, along with a complete donor chimerism in bone marrow. Meanwhile, the patient experienced moderate GVHD and immune-related adverse events (irAEs), successively involving the lung, liver, lower digestive tract and urinary system, which were well controlled by immunosuppressive therapies. As far as we know, this case is the first one to report the use of tislelizumab in combination with azacitidine to prevent post-transplant relapse in AML. In summary, the application of ICIs in MRD positive patients might be an attractive strategy for immune modulation in the future to reduce the incidence of HR in the post-transplant setting, but safer clinical application schedules need to be explored.

Strategies for the Prevention of Invasive Fungal Infections after Lung Transplant.

Long-term survival after lung transplantation is lower than that associated with other transplanted organs. Infectious complications, most importantly invasive fungal infections, have detrimental effects and are a major cause of morbidity and mortality in this population. Candida infections predominate in the early post-transplant period, whereas invasive mold infections, usually those related to Aspergillus, are most common later on. This review summarizes the epidemiology and risk factors for invasive fungal diseases in lung transplant recipients, as well as the current evidence on preventive measures. These measures include universal prophylaxis, targeted prophylaxis, and preemptive treatment. Although there is consensus that a preventive strategy should be implemented, current data show no superiority of one preventive measure over another. Data are also lacking regarding the optimal antifungal regimen and the duration of treatment. As all current recommendations are based on observational, single-center, single-arm studies, it is necessary that this longstanding debate is settled with a multicenter randomized controlled trial.

Human cytomegalovirus infection: A considerable issue following allogeneic hematopoietic stem cell transplantation.

Cytomegalovirus (CMV) is an opportunistic virus, whereby recipients are most susceptible following allogeneic hematopoietic stem cell transplantation (allo-HSCT). With the development of novel immunosuppressive agents and antiviral drugs, accompanied with the widespread application of prophylaxis and preemptive treatment, significant developments have been made in transplant recipients with human (H)CMV infection. However, HCMV remains an important cause of short- and long-term morbidity and mortality in transplant recipients. The present review summarizes the molecular mechanism and risk factors of HCMV reactivation following allo-HSCT, the diagnosis of CMV infection following allo-HSCT, prophylaxis and treatment of HCMV infection, and future perspectives. All relevant literature were retrieved from PubMed and have been reviewed.

Management of PTLD After Hematopoietic Stem Cell Transplantation: Immunological Perspectives.

Post-transplant lymphoproliferative disorders (PTLDs) are life-threatening complications of iatrogenic immune impairment after allogeneic hematopoietic stem cell transplantation (HSCT). In the pediatric setting, the majority of PTLDs are related to the Epstein-Barr virus (EBV) infection, and present as B-cell lymphoproliferations. Although considered rare events, PTLDs have been increasingly observed with the widening application of HSCT from alternative sources, including cord blood and HLA-haploidentical stem cell grafts, and the use of novel agents for the prevention and treatment of rejection and graft-vs.-host disease. The higher frequency initially paralleled a poor outcome, due to limited therapeutic options, and scarcity of controlled trials in a rare disease context. In the last 2 decades, insight into the relationship between EBV and the immune system, and advances in early diagnosis, monitoring and treatment have changed the approach to the management of PTLDs after HSCT, and significantly ameliorated the prognosis. In this review, we summarize literature on the impact of combined viro-immunologic assessment on PTLD management, describe the various strategies for PTLD prevention and preemptive/curative treatment, and discuss the potential of novel immune-based therapies in the containment of this malignant complication.

Antimicrobial Prophylaxis and Preemptive Approaches for the Prevention of Infections in the Stem Cell Transplant Recipient, with Analogies to the Hematologic Malignancy Patient.

Infectious complications represent one of the most common causes of morbidity and mortality in allogeneic hematopoietic cell transplant (HCT) recipients. Prophylactic and preemptive treatment strategies against bacterial, fungal, viral, and parasitic pathogens are routinely implemented during high-risk post-HCT periods at most transplant centers. The basic concepts and review of current guidelines of antibiotic prophylaxis and empirical/preemptive antibiotic treatment in allogeneic HCT recipients are reviewed in this article.

CMV Prevention and Treatment in Transplantation: What's New in 2019.

PURPOSE OF REVIEW: Transplant recipients are at risk for cytomegalovirus (CMV) infection and associated morbidity and mortality. We summarize recently introduced or currently investigated modalities for prevention and treatment of CMV infection in hematopoietic cell (HCT) and solid organ transplant (SOT) recipients. RECENT FINDINGS: Letermovir was recently approved for CMV prevention in HCT recipients. Data from real world studies support its role to improve outcomes in this population. Letermovir is currently under investigation for broader patient populations and indications. Maribavir is in late stages of development for CMV treatment and may provide a safer alternative to currently available anti-CMV drugs. Promising CMV vaccine candidates and adoptive cell therapy approaches are under evaluation. CMV immune monitoring assays are predicted to play a more central role in our clinical decision making. In recent years, major advances have been made in CMV prevention and treatment in transplant recipients. Rigorous research is ongoing and is anticipated to further impact our ability to improve outcomes in this population.

Management of toxoplasmosis in transplant recipients: an update.

INTRODUCTION: Toxoplasmosis is a life-threatening parasitic disease for hematopoietic stem cell transplant (HSCT) and solid organ transplant (SOT) recipients. The risk of toxoplasmosis in transplant patients mainly depends on the degree of immunosuppression, the tropism of Toxoplasma gondii for the grafted tissue, and the seroprevalence in the general population. Although transplant recipients with toxoplasmosis have a high mortality rate, there are neither well-defined recommendations nor a consensus for the management of this disease in these patients. Areas covered. This review focuses on the management of toxoplasmosis in transplant recipients and discusses the various strategies for diagnosis, prevention, treatment, and follow-up in clinical practice. The literature search was conducted on publications in English and French using the search terms 'Toxoplasma gondii,' 'organ transplant,' and 'transplant recipients.' Expert commentary. The diagnosis of toxoplasmosis has greatly improved over the last two decades, but it is still a fatal illness. Non-specificity of the symptoms, resulting in a delay before diagnosis, and therapeutic failure are the main causes of death. The development of active treatments against cysts is one of the current challenges that will considerably improve the management of toxoplasmosis in transplant recipients by clearing chronic infection to avoid T. gondii reactivation.

Uso profiláctico de antimicrobianos fuera de la práctica quirúrgica y de procedimientos invasivos: bases conceptuales y operativas / Prophylactic use of antimicrobials outside surgical and invasive-procedure settings: conceptual and operational basis

El uso preventivo de antimicrobianos es de larga data y no se restringe a antibacterianos. Lo más consensuado y estructurado es la profilaxis antimicrobiana perioperatoria y ante procedimientos invasivos. Fuera de este contexto hay gran cantidad de situaciones, menos caracterizadas, con riesgo de infecciones en que se usan ampliamente, muchas veces con menor sistematización. Esta presentación presenta las bases conceptuales y operativas de este segundo tipo de profilaxis. Conceptualmente la profilaxis primaria pretende evitar la infección por agente único conocido o variados, por exposición ambiental o susceptibilidad específica de ese hospedero y es implementable antes o después de la exposición. Producida esta infección la meta de la profilaxis secundaria intenta evitar la enfermedad y puede tomar dos modalidades, en infecciones sin evidencias de enfermedad clínica o daños, la profilaxis corresponde a "tratamiento de infección latente" y, si aún en ausencia de manifestaciones clínicas, hay elementos de laboratorio precoces premonitorios de progresión, la profilaxis se denomina "tratamiento anticipatorio". Se presentan operacionalmente y resumidas las situaciones en contexto médico no invasivo con uso potencial preventivo de antimicrobianos en base a agentes posibles, situaciones ambientales de riesgo, vulnerabilidad del hospedero, medicamentos a usar, su duración y efectividad con enfoque mayoritario en medicina de adultos.

Antimicrobial use with preventive purpose probably began shortly after its therapeutic use, especially antibiotics. More consensus and sistematization exist with perioperative and invasive procedures prophylaxis. However, beyond that context, there is great number of non invasive medical situations with high risk of secondary infections either by acquisition of pathogens or activation of latent ones, in which antimicrobials are routinely used with preventive purpose, albeit with less sistematization and consensus. This presentation aims to lay down the conceptual and operational basis for antimicrobial prophylaxis in these settings, whose objective is preventing an infection (primary prophylaxis) by a known or a variety of pathogens, either by person to person transmission, enviromental exposure or particular susceptibility of the host, and can be implemented before or after exposure. If already infected, the antimicrobial prophylaxis goal is to avoid progression to disease (secondary prevention) and may take two conceptual approaches; first, without clinical disease but significant risk of progression, the modality can be called "treatment of latent infection". In the second, also clinically asymptomatic, but with premonitory laboratoy signs of impending progression present, early use of antimicrobial is called "preemptive treatment". This presentation will describe the most frequent medical situations where preventive use of antimicrobials is employed, together with the medications most consensually used, according to the host, the agent(s) and medical situation, with emphasis in adults.

Top Questions in the Diagnosis and Treatment of Coccidioidomycosis.

Revised and greatly expanded treatment guidelines for coccidioidomycosis were published last year by the Infectious Diseases Society of America. We have selected 4 questions that commonly arise in the management of patients suspected of this disease and for which there remain divided opinions.