Characterization of immune exhaustion and suppression in the tumor microenvironment of splenic marginal zone lymphoma.

The role of the tumor microenvironment (TME) and intratumoral T cells in splenic marginal zone lymphoma (sMZL) is largely unknown. In the present study, we evaluated 36 sMZL spleen specimens by single cell analysis to gain a better understanding of the TME in sMZL. Using mass cytometry (CyTOF), we observed that the TME in sMZL is distinct from that of control non-malignant reactive spleen (rSP). We found that the number of TFH cells varied greatly in sMZL, ICOS+ TFH cells were more abundant in sMZL than rSP, and TFH cells positively correlated with increased numbers of memory B cells. Treg cell analysis revealed that TIGIT+ Treg cells are enriched in sMZL and correlate with suppression of TH17 and TH22 cells. Intratumoral CD8+ T cells were comprised of subsets of short-lived, exhausted and late-stage differentiated cells, thereby functionally impaired. We observed that T-cell exhaustion was present in sMZL and TIM-3 expression on PD-1low cells identified cells with severe immune dysfunction. Gene expression profiling by CITE-seq analysis validated this finding. Taken together, our data suggest that the TME as a whole, and T-cell population specifically, are heterogenous in sMZL and immune exhaustion is one of the major factors impairing T-cell function.

Demographics, Motivations, and Experiences of Participants in Transplantation or Cellular Therapy Fellowships.

Recent American Society for Transplantation and Cellular Therapy guidelines have sought to establish clinical and research expectations for participants in blood and marrow transplantation (BMT) and cellular therapy (CT) fellowships. However, little is known about participants in BMT/CT fellowships and the value they find from this additional training. We wanted to characterize the demographics, motivations, and experiences of recent participants in BMT/CT fellowships. We developed a 27-item online survey addressing backgrounds, application processes, training experiences, and perceived benefits among physicians who had started a clinical U.S.-based BMT/CT fellowship between 2012 to 2021. Anonymous responses were solicited through program director outreach, society website postings, targeted emails, and social media. Of 105 respondents (44% pediatric trainees), 4% were URMs and 39% were non-U.S. IMGs. The most important motivations for applying were comfort with allogeneic BMT, improved career prospects, and opportunities for research and publication. Almost all respondents (92%) attended donor selection meetings, whereas smaller proportions visited cell processing facilities (65%), HLA laboratories (57%), or good manufacturing practice facilities (22%). Most respondents reported ≥1 publication (26% reported 4+) based on research or experiences during their fellowship. Respondents reported improved post-fellowship comfort with all queried BMT/CT-related competencies. Seventy percent of respondents stated that they would recommend their fellowship highly to others; this corresponded to a Net Promoter Score of +65%, consistent with a strongly positive experience. Most respondents reported currently being in clinical practice (89% at academic centers), with a median of 70% of time currently spent caring for BMT/CT recipients. Although limited by recruitment methods and recall bias, our study demonstrated that BMT/CT fellowships are effective at increasing comfort with BMT/CT management and that most participants would highly recommend this BMT/CT training to others. Nevertheless, our study identified substantial heterogeneity in clinical responsibilities and BMT/CT-related laboratory exposure. The high representation of non-U.S. IMGs underscores the distinct role of BMT/CT fellowships for this group, whereas improved URM recruitment remains an important future direction for the field. Whether advanced fellowships will ever become required for the future BMT/CT workforce, analogous to the additional training required for solid organ transplantation in other medical and pediatric subspecialties, remains uncertain.

Outcomes of first therapy after CD19-CAR-T treatment failure in large B-cell lymphoma.

Persistence or recurrence of large B-cell lymphoma after CD19-CAR-T is common, yet data guiding management are limited. We describe outcomes and features following CAR-T treatment failure. Of 305 adults who received CD19-CAR-T, 182 experienced disease recurrence or progression (1-year cumulative incidence 63% [95%CI: 57-69]). Of 52 post-CAR-T biopsies evaluated by flow cytometry, 49 (94%) expressed CD19. Subsequent anti-cancer treatment was administered in 135/182 (74%) patients with CAR-T treatment failure. Median OS from the first post-CAR-T treatment was 8 months (95%CI 5.6-11.0). Polatuzumab-, standard chemotherapy-, and lenalidomide-based treatments were the most common approaches after CAR-T. No complete responses (CRs) were observed with conventional chemotherapy, while CR rates exceeding 30% were seen following polatuzumab- or lenalidomide-based therapies. Factors associated with poor OS among patients treated post-CAR-T were pre-CAR-T bulky disease (HR 2.27 [1.10-4.72]), lack of response to CAR-T (2.33 [1.02-5.29]), age >65 years (HR 2.65 [1.49-4.73]) and elevated LDH at post-CAR-T treatment (HR 2.95 [1.61-5.38]). The presence of ≥2 of these factors was associated with inferior OS compared to ≤1 (56% vs. 19%). In this largest analysis to date of patients who progressed or relapsed after CD19-CAR-T, survival is poor, though novel agents such as polatuzumab and lenalidomide may have hold promise.

Brentuximab vedotin as a bridge to combination chemotherapy in gray zone lymphoma with severe liver impairment: a case report.

Background: Gray zone lymphoma (GZL) is a rare lymphoma subtype characterized by features intermediate between diffuse large B-cell lymphoma (DLBCL) and classic Hodgkin lymphoma (cHL). The optimal first-line treatment for GZL remains undefined, particularly for patients with poor performance status or baseline organ impairment. Brentuximab vedotin (BV), a targeted therapy that binds to CD30, a TNFR superfamily member involved in NF-kB signaling, has shown promise in the treatment of CD30-positive lymphomas. However, its use in GZL, especially in patients with severe liver impairment, has not been reported previously. Case description: We present a case of a 37-year-old male with GZL and severe liver impairment at initial presentation. The patient initially received monotherapy with BV, which resulted in a marked improvement in liver enzymes and bilirubin levels. Subsequently, combination cytotoxic chemotherapy consisting of dose-adjusted etoposide, prednisone, cyclophosphamide, and doxorubicin (DA-EP_CH) was added. Repeat imaging revealed near complete resolution of lymphadenopathy and significant reduction in hepatosplenomegaly. The patient completed a full course of chemotherapy and achieved a complete response. Follow-up examinations showed no evidence of recurrent disease, and the patient resumed full-time work. Discussion: GZL poses diagnostic challenges due to its overlapping features with DLBCL and cHL. Accurate diagnosis relies on comprehensive histopathological evaluation, immunophenotyping, and molecular analysis. The optimal first-line treatment for GZL remains uncertain. BV shows promise as an addition to chemotherapy in GZL, even in the presence of severe liver impairment. The molecular pathogenesis of GZL is complex and heterogeneous, frequently involving aberrant NF-kB signaling and impaired apoptosis regulation via loss of TP53 expression. Understanding the underlying molecular mechanisms is essential for developing targeted therapies and identifying predictive biomarkers for treatment response. Conclusion: This case demonstrates the successful use of BV as a bridge to cytotoxic chemotherapy in a GZL patient with severe liver impairment, highlighting its potential safety and efficacy even in the setting of end-organ failure. Further investigation is warranted to define optimal treatment strategies, identify predictive biomarkers, and improve outcomes for patients with this rare and challenging lymphoma subtype.

Vitamin D Insufficiency and Clinical Outcomes with Chimeric Antigen Receptor T-Cell Therapy in Large B-cell Lymphoma.

Vitamin D insufficiency is a potentially modifiable risk factor for poor outcomes in newly diagnosed large B-cell lymphoma (LBCL). However, the role of circulating vitamin D concentrations in relapsed/refractory LBCL treated with CD19-directed chimeric antigen receptor T-cell therapy (CAR-T) is currently unknown. This was a single-center, observational study that evaluated the association of pre-CAR-T 25-hydroxyvitamin D (25-OHD) status with 100-day complete response, progression-free survival, overall survival, and CAR-T-related toxicity in 111 adult relapsed/refractory LBCL patients. Vitamin D insufficiency was defined as ≤30 ng/mL in accordance with the Endocrine Society guidelines. The median pre-CAR-T 25-hydroxyvitamin D concentration was 24 ng/mL (interquarile range = 18-34). Vitamin D-insufficient patients (≤30 ng/mL; n = 73 [66%]) were significantly younger than their vitamin D-replete (>30 ng/mL; n = 38 [34%]) counterparts (P= .039). The vitamin D-insufficient cohort was enriched for de novo LBCL as the histological subtype (P= .026) and had a higher proportion of tisagenlecleucel as the CAR-T product (P= .049). There were no other significant differences in the baseline characteristics between the two groups. In vitamin D-insufficient compared to -replete patients, 100-day complete response was 55% versus 76% (P= .029), and 2-year overall survival was 41% versus 71% (P= .061), respectively. In multivariate analysis, vitamin D insufficiency remained significantly associated with 100-day complete response (odds ratio 2.58 [1.05-6.83]; P= .045) and overall survival (hazard ratio 2.24 [1.08-4.66], P= .030). In recipients of tisagenlecleucel, vitamin D insufficiency was associated with significantly lower cell viability of the infused CAR-T product (P= .015). Finally, pretreatment vitamin D insufficiency did not predict for subsequent CAR-T-related toxicity. This is the first report to demonstrate that vitamin D insufficiency is associated with inferior clinical outcomes in CAR-T recipients. Further study into the mechanistic insights of this finding, and the potential role of vitamin D supplementation to optimize CAR-T are warranted.

Phenotype, Function, and Clinical Significance of CD26+ and CD161+Tregs in Splenic Marginal Zone Lymphoma.

PURPOSE: Regulatory T-cells (Treg) are essential to Tregs homeostasis and modulate the antitumor immune response in patients with lymphoma. However, the biology and prognostic impact of Tregs in splenic marginal zone lymphoma (SMZL) have not been studied. EXPERIMENTAL DESIGN: Biopsy specimens from 24 patients with SMZL and 12 reactive spleens (rSP) from individuals without lymphoma were analyzed by using CITE-seq (cellular indexing of transcriptomes and epitopes by sequencing), CyTOF (mass cytometry) analysis, and flow cytometry to explore the phenotype, transcriptomic profile, and clinical significance of intratumoral Tregs and their subsets. The biological characteristics and cell signaling pathways of intratumoral Treg subsets were confirmed by in vitro functional assays. RESULTS: We found that Tregs are more abundant in SMZL patients' spleens than rSP, and Tregs from patients with SMZL and rSP can be separated into CD161+Treg and CD26+Treg subsets. CD161+Tregs are increased in SMZL but have dysregulated immune function. We found that CD161+Treg and CD26+Tregs have unique gene expression and phenotypic profiles and are differentially correlated with patient outcomes. Specifically, increased CD161+Tregs are significantly associated with a favorable prognosis in patients with SMZL, whereas CD26+Tregs are associated with a poor prognosis. Furthermore, activation of the IL2/STAT5 pathway contributes to the induction of CD26+Tregs and can be reversed by STAT5 inhibition. CONCLUSIONS: IL2/STAT5-mediated expansion of CD26+Tregs contributes to a poor clinical outcome in SMZL and may represent a therapeutic opportunity in this disease.

Impact of TP53 Genomic Alterations in Large B-Cell Lymphoma Treated With CD19-Chimeric Antigen Receptor T-Cell Therapy.

PURPOSE: Tumor-intrinsic features may render large B-cell lymphoma (LBCL) insensitive to CD19-directed chimeric antigen receptor T cells (CAR-T). We hypothesized that TP53 genomic alterations are detrimental to response outcomes in LBCL treated with CD19-CAR-T. MATERIALS AND METHODS: Patients with LBCL treated with CD19-CAR-T were included. Targeted next-generation sequencing was performed on pre-CAR-T tumor samples in a subset of patients. Response and survival rates by histologic, cytogenetic, and molecular features were assessed. Within a cohort of newly diagnosed LBCL with genomic and transcriptomic profiling, we studied interactions between cellular pathways and TP53 status. RESULTS: We included 153 adults with relapsed or refractory LBCL treated with CD19-CAR-T (axicabtagene ciloleucel [50%], tisagenlecleucel [32%], and lisocabtagene maraleucel [18%]). Outcomes echoed pivotal trials: complete response (CR) rate 54%, median overall survival (OS) 21.1 months (95% CI, 14.8 to not reached), and progression-free survival 6 months (3.4 to 9.7). Histologic and cytogenetic LBCL features were not predictive of CR. In a subset of 82 patients with next-generation sequencing profiling, CR and OS rates were comparable with the unsequenced cohort. TP53 alterations (mutations and/or copy number alterations) were common (37%) and associated with inferior CR and OS rates in univariable and multivariable regression models; the 1-year OS in TP53-altered LBCL was 44% (95% CI, 29 to 67) versus 76% (65 to 89) in wild-type (P = .012). Transcriptomic profiling from a separate cohort of patients with newly diagnosed lymphoma (n = 562) demonstrated that TP53 alterations are associated with dysregulation of pathways related to CAR-T-cell cytotoxicity, including interferon and death receptor signaling pathway and reduced CD8 T-cell tumor infiltration. CONCLUSION: TP53 is a potent tumor-intrinsic biomarker that can inform risk stratification and clinical trial design in patients with LBCL treated with CD19-CAR-T. The role of TP53 should be further validated in independent cohorts.

High progression-free survival after intermediate intensity double unit cord blood transplantation in adults.

Cord blood transplantation (CBT) after high intensity or nonmyeloablative conditioning has limitations. We investigated cyclosporine-A/mycophenolate mofetil-based intermediate intensity (cyclophosphamide 50 mg/kg, fludarabine 150 mg/m2, thiotepa 10 mg/kg, total body irradiation 400 cGy) unmanipulated double-unit CBT (dCBT) with prioritization of unit quality and CD34+ cell dose in graft selection. Ninety adults (median age, 47 years [range, 21-63]; median hematopoietic cell transplantation comorbidity index, 2 [range, 0-8]; 61 [68%] acute leukemia) received double-unit grafts (median CD34+ cell dose, 1.3 × 105/kg per unit [range, 0.2-8.3]; median donor-recipient human leukocyte antigen (HLA) match, 5/8 [range 3-7/8]). The cumulative incidences of sustained CB engraftment, day 180 grade III-IV acute, and 3-year chronic graft-versus-host disease were 99%, 24%, and 7%, respectively. Three-year transplant-related mortality (TRM) and relapse incidences were 15% and 9%, respectively. Three-year overall survival (OS) is 82%, and progression-free survival (PFS) is 76%. Younger age and higher engrafting unit CD34+ cell dose both improved TRM and OS, although neither impacted PFS. Engrafting unit-recipient HLA match was not associated with any outcome with a 3-year PFS of 79% in 39 patients engrafting with 3-4/8 HLA-matched units. In 52 remission acute leukemia patients, there was no association between minimal residual disease (MRD) and 3-year PFS: MRD negative of 88% vs MRD positive of 77% (P = .375). Intermediate intensity dCBT is associated with high PFS. Use of highly HLA mismatched and unmanipulated grafts permits wide application of this therapy, and the low relapse rates support robust graft-versus-leukemia effects even in patients with MRD.

Anti-CD19 chimeric antigen receptor T-cell therapy in acute lymphocytic leukaemia: a systematic review and meta-analysis.

BACKGROUND: Anti-CD19 chimeric antigen receptor (CAR) T-cell therapy has shown remarkable activity in patients with refractory or relapsed acute lymphocytic leukaemia. Various anti-CD19 CAR T-cell constructs have been trialled and responses vary widely among different studies. We aimed to systematically analyse the outcomes of patients with acute lymphocytic leukaemia treated with anti-CD19 CAR T cells and identify factors associated with differences in outcomes. METHODS: We did a systematic review and meta-analysis of published and unpublished clinical trials that reported data on the outcomes of adult or paediatric patients that were treated with anti-CD19 CAR T cells for relapsed or refractory B-cell acute lymphocytic leukaemia, reported between Jan 1, 2012, and April 14, 2020. Studies with two patients or fewer were excluded and summary data were extracted from the reports. The primary outcome was the number of patients who had complete remission at any time after anti-CD19 CAR T-cell infusion. This study is not registered in PROSPERO. FINDINGS: From 1160 studies, we identified 40 potentially appropriate studies, 35 (88%) of which met the eligibility criteria and were included in the final analysis (n=953 patients). The pooled complete remission was 80% (95% CI 75·5-84·8) and heterogeneity between studies was moderate (I2=56·96%). In the prespecified subgroup analyses, 195 (75% [95% CI 66·9-82·9, I2=35·22%]) of 263 patients in adult studies and 242 (81% [72·9-87·2, I2=54·45%]) of 346 patients in paediatric studies achieved complete remission, p=0·24. The pooled complete remission did not significantly differ with anti-CD19 CAR T-cell construct type or single-chain variable fragment clone, but was higher with autologous T-cell origin (727 [83%, 78·5-86·5, I2=44·34%] of 901 patients), compared with allogeneic T-cell origin (29 [55%, 30·6-79·0, I2=62·64%] of 52 patients; p=0·018). 242 (26% [95% CI 18·5-34·1]) of 854 patients developed grade 3 or worse cytokine release syndrome and 97 (12% [6·6-19·2]) of 532 developed grade 3 or worse neurotoxicity. There was no difference in the proportion of patients who achieved complete remission or who had cytokine release syndrome or neurotoxicity between different anti-CD19 CAR T-cell constructs. The risk of bias was assessed as low in 17 studies and moderate in 18 studies. INTERPRETATION: The high response rates after anti-CD19 CAR T-cell therapy can be used to guide the use of therapy in patients with relapsed or refractory acute lymphocytic leukaemia. Comparison studies are required to further determine differences in efficacy between different anti-CD19 CAR T-cell constructs in the setting of relapsed or refractory acute lymphocytic leukaemia. FUNDING: National Cancer Institute, National Comprehensive Cancer Network, Mayo Clinic K2R Research Pipeline, and Mayo Clinic Center for Individualized Medicine.

Immunomodulators in Lymphoma.

OPINION STATEMENT: Lymphomas are highly heterogeneous tumors and different histologies are characterized by significant differences in biology. Despite the structural and molecular differences between lymphoma types, it is well recognized that the tumor microenvironment plays a critical role in the lymphoma survival and growth. Over the past few years, understanding of this notion has brought immunotherapy to the forefront of lymphoma treatment by targeting the tumor microenvironment in order to produce an effective anti-tumor response. Thus, the area of lymphoma therapy has changed dramatically within the past few years with the use of checkpoint inhibitors and more recently CAR T-cells. Remarkable results have been reported in some lymphoma types but responses vary significantly between different histologies. Future approaches will focus on combination strategies that will attack lymphoma cells in addition to activating immune responses. These strategies include combinations of different checkpoint blocking antibodies, combinations of checkpoint blocking antibodies with agonistic antibodies, immunomodulatory agents, small molecule inhibitors or CAR T-cells, and armored CAR T-cells. A number of clinical trials testing such combinations are currently under way. In this review, we discuss strategies to modulate the immune response in lymphoma. We specifically address the obstacles to effective activation of the immune system against malignant B-cells and review the current approaches that try to overcome these barriers.

Clinical and laboratory features of autoimmune hemolytic anemia associated with immune checkpoint inhibitors.

Immune checkpoint inhibitors (ICPis) are a novel class of immunotherapeutic agents that have revolutionized the treatment of cancer; however, these drugs can also cause a unique spectrum of autoimmune toxicity. Autoimmune hemolytic anemia (AIHA) is a rare, but often severe, complication of ICPis. We identified 14 patients from nine institutions across the United States who developed ICPi-AIHA. The median interval from ICPi initiation to development of AIHA was 55 days (interquartile range [IQR], 22-110 days). Results from the direct antiglobulin test (DAT) were available for 13 of 14 patients: 8 patients (62%) had a positive DAT and 5 (38%) had a negative DAT. The median pretreatment and nadir hemoglobin concentrations were 11.8 g/dL (IQR, 10.2-12.9 g/dL) and 6.3 g/dL (IQR, 6.1-8.0 g/dL), respectively. Four patients (29%) had a preexisting lymphoproliferative disorder, and two (14%) had a positive DAT prior to initiation of ICPi therapy. All patients were treated with glucocorticoids, with three requiring additional immunosuppressive therapy. Complete and partial recoveries of hemoglobin were achieved in 12 (86%) and 2 (14%) patients, respectively. Seven patients (50%) were rechallenged with ICPis, and one (14%) developed recurrent AIHA. Clinical and laboratory features of ICPi-AIHA were similar in DAT positive and negative patients. ICPi-AIHA shares many clinical features with primary AIHA; however, a unique aspect of ICPi-AIHA is a high incidence of DAT negativity. Glucocorticoids are an effective first-line treatment in the majority of patients with ICPi-AIHA, and most patients who are rechallenged with an ICPi do not appear to develop recurrence of AIHA.

Spotlight on ponatinib in the treatment of chronic myeloid leukemia and Philadelphia chromosome-positive acute lymphoblastic leukemia: patient selection and perspectives.

Ponatinib, a third-generation tyrosine kinase inhibitor that inhibits BCR/ABL independent of the mutation status, is currently approved for the treatment of patients with chronic myeloid leukemia or acute lymphoblastic leukemia that are either resistant or unable to tolerate another tyrosine kinase inhibitor. Its US Food and Drug Administration approval was based on results from long-term follow-up of the pivotal Phase II PACE trial, which demonstrated deep and durable molecular responses in the treated patients. Despite the remarkable responses, ponatinib has been associated with high frequency of severe vascular events, which led to its withdrawal from the market in 2013. Following analysis of the risk factors of patients who developed vascular side effects, ponatinib was reintroduced in the market 1 year later with specific dose-reduction recommendations and carrying a black box warning. Thus, careful patient selection with identification of patients whose potential benefit from ponatinib exceeds the potential risks associated with its use is crucial. Ongoing and future studies are focusing on earlier detection of mutations, strategies to minimize side effects, and potential expansion of the treatment indications. Clinical trials testing the safety and efficacy of ponatinib as frontline therapy are ongoing.

The PD1:PD-L1/2 Pathway from Discovery to Clinical Implementation.

The immune system maintains a critically organized network to defend against foreign particles, while evading self-reactivity simultaneously. T lymphocytes function as effectors and play an important regulatory role to orchestrate the immune signals. Although central tolerance mechanism results in the removal of the most of the autoreactive T cells during thymic selection, a fraction of self-reactive lymphocytes escapes to the periphery and pose a threat to cause autoimmunity. The immune system evolved various mechanisms to constrain such autoreactive T cells and maintain peripheral tolerance, including T cell anergy, deletion, and suppression by regulatory T cells (TRegs). These effects are regulated by a complex network of stimulatory and inhibitory receptors expressed on T cells and their ligands, which deliver cell-to-cell signals that dictate the outcome of T cell encountering with cognate antigens. Among the inhibitory immune mediators, the pathway consisting of the programed cell death 1 (PD-1) receptor (CD279) and its ligands PD-L1 (B7-H1, CD274) and PD-L2 (B7-DC, CD273) plays an important role in the induction and maintenance of peripheral tolerance and for the maintenance of the stability and the integrity of T cells. However, the PD-1:PD-L1/L2 pathway also mediates potent inhibitory signals to hinder the proliferation and function of T effector cells and have inimical effects on antiviral and antitumor immunity. Therapeutic targeting of this pathway has resulted in successful enhancement of T cell immunity against viral pathogens and tumors. Here, we will provide a brief overview on the properties of the components of the PD-1 pathway, the signaling events regulated by PD-1 engagement, and their consequences on the function of T effector cells.

Galactomannan and Polymerase Chain Reaction-Based Screening for Invasive Aspergillosis Among High-Risk Hematology Patients: A Diagnostic Meta-analysis.

BACKGROUND: Screening of high-risk patients for invasive aspergillosis (IA) has the potential to decrease the use of empiric antifungal agents. However, the performance of different screening methods has not been studied. METHODS: We performed a meta-analysis of published studies to assess the diagnostic performance of galactomannan (GM) and polymerase chain reaction (PCR) as weekly screening tests in high-risk populations. The sensitivity and specificity of 6 approaches combining GM and PCR were estimated using the bivariate model. RESULTS: Thirteen studies with 1670 patients met our inclusion criteria. Single positive test results had modest sensitivity and specificity for screening (respectively, 92% and 90% for GM; 84% and 76% for PCR). The screening approach with the highest sensitivity was the one that used at least 1 GM- or PCR-positive result to define a positive episode, achieving a sensitivity of 99%, significantly higher than any single test (P = .0018 compared with GM and P < .0001 compared with PCR). Meanwhile, when both GM and PCR were positive for the same patient, the specificity increased to 98%, which was not significantly different compared to the specificity of at least 2 positive GM (95%, P = .56 for the comparison) or PCR results (93%, P = .07 for the comparison). CONCLUSIONS: When screening high-risk patients for IA with GM and PCR tests, the absence of any positive test can obviate the need for antifungal agents with a negative predictive value of 100%, whereas the presence of at least 2 positive results is highly suggestive of an active infection with a positive predictive value of 88%.

Molecular and nonmolecular diagnostic methods for invasive fungal infections.

Invasive fungal infections constitute a serious threat to an ever-growing population of immunocompromised individuals and other individuals at risk. Traditional diagnostic methods, such as histopathology and culture, which are still considered the gold standards, have low sensitivity, which underscores the need for the development of new means of detecting fungal infectious agents. Indeed, novel serologic and molecular techniques have been developed and are currently under clinical evaluation. Tests like the galactomannan antigen test for aspergillosis and the ß-glucan test for invasive Candida spp. and molds, as well as other antigen and antibody tests, for Cryptococcus spp., Pneumocystis spp., and dimorphic fungi, have already been established as important diagnostic approaches and are implemented in routine clinical practice. On the other hand, PCR and other molecular approaches, such as matrix-assisted laser desorption ionization (MALDI) and fluorescence in situ hybridization (FISH), have proved promising in clinical trials but still need to undergo standardization before their clinical use can become widespread. The purpose of this review is to highlight the different diagnostic approaches that are currently utilized or under development for invasive fungal infections and to identify their performance characteristics and the challenges associated with their use.