Shedding light on IRIS: from Pathophysiology to Treatment of Cryptococcal Meningitis and Immune Reconstitution Inflammatory Syndrome in HIV-Infected Individuals

Updates in Cryptococcosis

Cryptococcosis is an invasive fungal infection caused by yeasts of the genus Cryptococcus that causes a significant global burden of disease in both immunocompromised and immunocompetent individuals. Over the past several decades, diagnosis and management of cryptococcal disease have moved to focus on rapid, reliable, and cost-effective care delivery, with the advent of new antigen detection assays and novel antifungal treatment strategies.

Deciphering prognostic indicators in non-HIV cryptococcal meningitis: Constructing and validating a predictive Nomogram model

Cryptococcal meningitis (CM) is a well-recognized fungal infection, with substantial mortality in individuals infected with the human immunodeficiency virus (HIV). However, the incidence, risk factors, and outcomes in non-HIV adults remain poorly understood. This study aims to investigate the characteristics and prognostic indicators of CM in non-HIV adult patients, integrating a novel predictive model to guide clinical decision-making. A retrospective cohort of 64 non-HIV adult CM patients, including 51 patients from previous studies and 13 from the First Hospital of Shanxi Medical University, was analyzed. We assessed demographic features, underlying diseases, intracranial pressure, cerebrospinal fluid characteristics, and brain imaging. Using the least absolute shrinkage and selection operator (LASSO) method, and multivariate logistic regression, we identified significant variables and constructed a Nomogram prediction model. The model's calibration, discrimination, and clinical value were evaluated using the Bootstrap method, calibration curve, C index, goodness-of-fit test, receiver operating characteristic (ROC) analysis, and decision curve analysis. Age, brain imaging showing parenchymal involvement, meningeal and ventricular involvement, and previous use of immunosuppressive agents were identified as significant variables. The Nomogram prediction model displayed satisfactory performance with an akaike information criterion (AIC) value of 72.326, C index of 0.723 (0.592-0.854), and area under the curve (AUC) of 0.723, goodness-of-fit test P = 0.995. This study summarizes the clinical and imaging features of adult non-HIV CM and introduces a tailored Nomogram prediction model to aid in patient management. The identification of predictive factors and the development of the nomogram enhance our understanding and capacity to treat this patient population. The insights derived have potential clinical implications, contributing to personalized care and improved patient outcomes.

JAK/STAT Signaling Predominates in Human and Murine Fungal Post-infectious Inflammatory Response Syndrome

Post-infection inflammatory syndromes have been increasingly recognized as a cause of host damage in a variety of infectious diseases including tuberculosis, bacterial meningitis, and COVID-19. Recently, a post-infectious inflammatory response syndrome (PIIRS) was described in non-HIV-infected cryptococcal fungal meningoencephalitis (CM) as a major cause of mortality. Inflammatory syndromes are particularly severe in neurological infections due to the skull's rigid structure which limits unchecked tissue expansion from inflammatory-induced edema. In the present studies, neurologic transcriptional pathway analysis utilizing a murine PIIRS model demonstrated a predominance of Janus kinase/signal transducer and activator of transcription (JAK/STAT) activation. JAK/STAT inhibitor treatment resulted in improvements in CNS damage markers, reductions in intrathecal CD44hiCD62lo CD4+ effector CD4+ T-cells and MHC II+ inflammatory myeloid cells, and weight gains in mice, the latter after treatment with antifungals. Based on these data, pathway-driven steroid-sparing human treatment for steroid-refractory PIIRS was initiated using short courses of the JAK/STAT inhibitor ruxolitinib. These were well tolerated and reduced activated HLA-DR+ CD4+ and CD8+ cells and inflammatory monocytes as well as improved brain imaging. Together, these findings support the role of JAK/STAT in PIIRS as well as further study of JAK/STAT inhibitors as potential adjunctive therapy for PIRS and other neural inflammatory syndromes.

Tocilizumab as a Potential Adjunctive Therapy to Corticosteroids in Cryptococcal Post-infectious Inflammatory Response Syndrome (PIIRS): a Report of Two Cases

PURPOSE

Non-HIV cryptococcal meningoencephalitis (CM) in previously healthy individuals is often complicated by a post-infectious inflammatory response syndrome (c-PIIRS) characterized by neurologic deterioration after appropriate antifungal therapy with sterilization of CSF fungal cultures. c-PIIRS results from an excessive inflammatory response to fungal antigens released during fungal lysis, mediated by IFN-γ, IL-6, and activated T-helper cells, leading to immune-mediated host damage that responds to pulse-corticosteroid taper therapy (PCT). Typically, oral steroids may take up to a year to taper, and occasionally, patients will be refractory to steroid therapy or may demonstrate high-risk lesions such as those involving intracranial arteries. Also, patients can have problematic side effects from prolonged corticosteroids. Hence, appropriate adjunctive agents are needed to reduce corticosteroid doses in the treatment of c-PIIRS. Due to a possible role of IL-6 in pathogenesis, IL-6 receptor blockade by tocilizumab may be useful in the treatment of c-PIIRS.

METHODS

Two previously healthy patients with non-HIV cPIIRS were seen at the NIH. Due to concerns for intracranial vascular rupture in an area of inflammation (Patient 1) and intractable symptoms on high-dose oral corticosteroids (Patient 2) with evidence of persistent CSF inflammation, patients were treated with 4-8 mg/kg tocilizumab every 2 weeks while maintained on a constant dose of prednisone.

RESULTS

Two patients exhibited rapid immunological improvement following treatment with tocilizumab. Patient 1 remained vascularly stable, and Patient 2 had near resolution of headaches with improvement in mental status as evidenced by improved MOCA score. The two had improved CSF inflammatory parameters and no significant side effects. Both CSF cultures remained negative throughout treatment.

CONCLUSIONS

Tocilizumab may be a safe adjunctive treatment for CM-related PIIRS suggesting further study.

Current knowledge of the immune reconstitution inflammatory syndrome in Whipple disease: a review

Immune reconstitution inflammatory syndrome (IRIS) is characterized by exaggerated and dysregulated inflammatory responses that occur as a result of reconstitution of adaptive or innate immunity. A wide range of microorganisms have been found to be associated with IRIS, such as human immunodeficiency virus (HIV), Mycobacterium and actinobacteria. Whipple disease (WD) is an infectious disorder caused by the Gram-positive bacterium Tropheryma whipplei (T. whipplei) and IRIS also serves as a complication during its treament. Although many of these pathological mechanisms are shared with related inflammatory disorders, IRIS in WD exhibits distinct features and is poorly described in the medical literature. Novel investigations of the intestinal mucosal immune system have provided new insights into the pathogenesis of IRIS, elucidating the interplay between systemic and local immune responses. These insights may be used to identify monitoring tools for disease prevention and to develop treatment strategies. Therefore, this review synthesizes these new concepts in WD IRIS to approach the feasibility of manipulating host immunity and immune reconstitution of inflammatory syndromes from a newer, more comprehensive perspective and study hypothetical options for the management of WD IRIS.

Clinical metagenomics-assisted diagnosis of relapsed HIV-associated cryptococcal meningitis

To date, the identification of crypotococcal relapse remains clinically challenging as it often has similar manifestation with paradoxical immune reconstitution inflammatory syndrome. This study reports on the use of metagenomics assisted next generation sequencing to aid in diagnosing recurrent cryptococcal meningitis in an person living with HIV experiencing recurring symptoms, despite negative culture results for Cryptococcus neoformans in the cerebrospinal fluid. Although fungal culture was negative, when reads from metagenomic and metatranscriptomic sequencing performed on the Day 308 cerebrospinal fluid sample were mapped onto the genome from the Day 4 isolate, 589 specific reads were identified. NCBI BLAST search also revealed Cryptococcus-specific 18S/25S/28S ribosomal RNA, indicating a relapse of the disease.

Thalidomide for Recurrence of Symptoms following HIV-Associated Cryptococcal Meningitis

INTRODUCTION

Cryptococcal meningitis (CM) is a serious and fatal fungal infection that affects individuals infected with human immunodeficiency virus (HIV). Despite treatment, recurrence of symptoms is common and could lead to poor outcomes. Corticosteroids are not always useful in treating symptom recurrence following HIV/CM; thus, alternative therapy is needed. Thalidomide has been reported to be effective in treating symptom recurrence in several patients with HIV/CM. This retrospective study aimed to investigate the efficacy and safety of thalidomide in the treatment of symptom recurrence following HIV/CM.

METHODS

Patients who were treated with thalidomide for symptom recurrence following HIV/CM were retrospectively included. Clinical outcomes and adverse events were recorded and analyzed.

RESULTS

Sixteen patients admitted between July 2018 and September 2020 were included in the analysis. During a median follow-up period of 295 (166, 419) days, all patients achieved clinical improvement in a median of 7 (4, 20) days. Among them, nine (56%) achieved complete resolution of symptoms at a median of 187 (131, 253) days, including 40% (2/5) of immune reconstitution inflammatory syndrome (IRIS), 50% (3/6) of patients with elevated ICP only, and 80% (4/5) of patients with symptoms only. Seven (43%) patients experienced nine episodes of adverse events, but no severe adverse event attributable to thalidomide was observed. None of the patients withdrew from thalidomide due to adverse events.

CONCLUSION

Thalidomide appears to be effective and safe in treating different types of symptom recurrence in HIV/CM. This study provides preliminary evidence supporting future randomized clinical trials to further investigate the efficacy and safety of thalidomide in treating symptom recurrence in this population.

Neurological worsening during treatment of HIV-negative cryptococcal meningitis in a patient with Evans syndrome

A 49-year-old woman with a rare autoimmune hematological disease, Evans syndrome, was admitted to the authors' hospital with immune reconstitution inflammatory syndrome-like reconstitution syndrome after effective antifungal therapy for cryptococcal meningitis. She initially improved after receiving corticosteroid treatment; after prednisone was tapered, her clinical presentation and brain imaging deteriorated but finally improved with the addition of thalidomide. Immune reconstitution inflammatory syndrome-like reconstitution syndrome is a rare complication in cryptococcal meningitis patients receiving immunosuppressive therapy. Thalidomide can be given in addition to corticosteroid therapy to effectively control the paradoxical inflammatory response and improve clinical outcomes.

Efficacy and safety of lenalidomide in HIV-associated cryptococcal meningitis patients with persistent intracranial inflammation: an open-label, single-arm, prospective interventional study

BACKGROUND

Patients with human immunodeficiency virus-associated cryptococcal meningitis (HIV-CM) have persistent intracranial inflammation despite negative cerebrospinal fluid (CSF) fungal cultures after optimal treatment for CM, which could be devastating for the central nervous system. However, a definitive treatment strategy for persistent intracranial inflammation despite optimal antifungal therapies is undefined.

METHODS

We identified 14 HIV-CM patients with persistent intracranial inflammation and conducted a 24-week, prospective, interventional study. All participants received lenalidomide (25 mg, p.o.) on days 1 to 21 of a 28-day cycle. Follow-up lasted for 24 weeks with visits at baseline and weeks 4, 8, 12, and 24. The primary endpoint was the change in clinical manifestations, routine CSF parameters, and MRI findings after lenalidomide treatment. An exploratory analysis was made on changes in cytokine levels in CSF. Safety and efficacy analyses were undertaken in patients who received at least one dose of lenalidomide.

RESULTS

Of 14 participants, 11 patients completed the 24 weeks of follow-up. Rapid clinical remission following lenalidomide therapy was observed. Clinical manifestations (fever, headache, altered mentation) were reversed fully by week-4 and remained stable during follow-up. A significant reduction in white blood cell (WBC) count in CSF was noted occurred at week-4 (P = 0.009). The median protein concentration in CSF decreased from 1.4 (0.7-3.2) g/L at baseline to 0.9 (0.6-1.4) at week-4 (P = 0.004). The median albumin concentration in CSF decreased from 79.2 (48.4-149.8) mg/L at baseline to 55.3 (38.3-89.0) mg/L at week-4 (P = 0.011). The WBC count, protein level, and albumin level in CSF remained stable and approached a normal range through week-24. There was no significant change in immunoglobulin-G, intracranial pressure (ICP), or chloride-ion concentration at each visit. Brain MRI demonstrated multiple lesions to be absorbed post-therapy. Levels of tumor necrosis factor-α granulocyte colony stimulating factor, interleukin (IL)-6, and IL-17A decreased significantly during 24-week follow-up. Two (14.3%) patients had mild skin rash, which resolved spontaneously. Lenalidomide-related serious adverse events were not observed.

CONCLUSION

Lenalidomide could improve persistent intracranial inflammation in HIV-CM patients significantly and was well tolerated without serious adverse events observed. And the additional randomized controlled study is required to further validate the finding.

Lenalidomide Improves Cognitive Function and Reduces Immune Reconstitution Inflammatory Syndrome in HIV-1-Related Cryptococcal Meningitis

Cryptococcal meningitis (CM) is a common opportunistic infection in patients with acquired immune deficiency syndrome. Although there is a standardized treatment for CM, some patients still have CM-associated immune reconstitution inflammatory syndrome (IRIS) after anti-cryptococcal and antiretroviral therapy, which manifests as cognitive impairment. We report two cases of CM-associated IRIS in human immunodeficiency virus (HIV) patients that were treated with lenalidomide. The treatment yielded a rapid clinical remission and improved cognitive function in both patients; their Montreal Cognitive Assessment (MoCA) and International HIV Dementia Scale (IHDS) scores improved. Furthermore, we evaluated changes in 32 cytokines in the cerebrospinal fluid of two patients and found that both MoCA and IHDS were significantly negatively correlated with inflammation-related factors (growth-related oncogene, interleukin [IL]-10, IL-2, IL-8, macrophage inflammatory protein-1β, tumor necrosis factor [TNF]-α) and significantly positively correlated with dementia-related factors (αβ42 and total tau). Our study reveals the potential of lenalidomide in treating cognitive impairment caused by immune-mediated inflammation in patients with HIV-CM. Moreover, we speculate that lenalidomide improves cognitive function by regulating intracranial inflammation via multiple pathways, not only by TNF-α blocking.

A nomogram for predicting paradoxical immune reconstitution inflammatory syndrome associated with cryptococcal meningitis among HIV-infected individuals in China

BACKGROUND

Cryptococcal meningitis (CM) associated immune reconstitution inflammatory syndrome (CM-IRIS) is the second most common complication in HIV-infected individuals with cryptococcal meningitis, with a reported mortality rate ranging from 8 to 30%. Given the devastating consequences of CM-IRIS related intracranial neuroinflammation and its challenging in diagnosis, we conducted a study to explore the risk factors and the occurrence of paradoxical CM-IRIS in HIV-infected patients, which is of great value for prevention and clinical management.

METHODS

We conducted a retrospective cohort study to identify the indicators associated with paradoxical CM-IRIS among 86 HIV-infected patients with CM using univariate and multivariate cox analysis. A nomogram was constructed using selected variables to evaluate the occurrence of paradoxical CM-IRIS at 6 months and 12 months after ART initiation. The discrimination and calibration of the nomogram were assessed by concordance index (C-index) and calibration plots. Decision curves analysis (DCA) were used to evaluate clinical effectiveness of the nomogram. Subsequently, to help clinicians recognize patients at high risk faster, patients were divided into high-risk and low-risk groups according to the best cutoff point identified by X-tile.

RESULTS

Of 86 AIDS patients with CM, 22.1% experienced paradoxical CM-IRIS at a median of 32 days after antiretroviral therapy (ART) initiation. The occurrence of paradoxical CM-IRIS was associated with age, ART initiation within 4 weeks of antifungal treatment, a four-fold increase in CD4 T cell counts, C-reactive protein levels, and hemoglobin levels independently. These five variables were further used to construct a predictive nomogram. The C-index (0.876) showed the favorable discriminative ability of the nomogram. The calibration plot revealed a high consistency between the predicted and actual observations. DCA showed that the nomogram was clinically useful. Risk stratification based on the total score of the nomogram showed well-differentiated in the high-risk and low-risk groups. Clinicians should pay attention to patients with total points high than 273.

CONCLUSIONS

We identified the predictive factors of paradoxical CM-IRIS and constructed a nomogram to evaluate the occurrence of paradoxical CM-IRIS in 6 months and 12 months. The nomogram represents satisfactory performance and might be applied clinically to the screening and management of high-risk patients.

What to Do for Increasing Cancer Burden on the African Continent? Accelerating Public Health Diagnostics Innovation for Prevention and Early Intervention on Cancers

No other place illustrates the increasing burden of cancer than in Africa and in particular, sub-Saharan Africa. Many of the individuals to be diagnosed with cancer will be in low-resource settings in the future due to, for example, an increase in populations and aging, and high co-morbidity with infections with viruses such as human immunodeficiency virus (HIV) and human papillomavirus (HPV), as well as the presence of infectious agents linked to cancer development. Due to lack of prevention and diagnostic innovation, patients present with advanced cancers, leading to poor survival and increased mortality. HIV infection-associated cancers such as B cell lymphomas, Kaposi's sarcoma, and HPV-associated cancers such as cervical cancer are particularly noteworthy in this context. Recent reports show that a host of other cancers are also associated with viral infection and these include lung, oral cavity, esophageal, and pharyngeal, hepatocellular carcinoma, and anal and vulvar cancers. This article examines the ways in which diagnostic innovation empowered by integrative biology and informed by public health priorities can improve cancer prevention or early intervention in Africa and beyond. In addition, I argue that because diagnostic biomarkers can often overlap with novel therapeutic targets, diagnostics research and development can have broader value for and impact on medical innovation.

Cryptococcosis

Cryptococcosis is an invasive fungal infection of global significance caused by yeasts of the genus Cryptococcus. The prevalence of HIV in certain areas of the world and the expanding population of immunocompromised patients contribute to the ongoing global disease burden. Point-of-care serologic testing has allowed for more rapid diagnosis and implementation of screening programs in resource-limited settings. Management involves therapy aimed at reduction in fungal burden, maintenance of intracranial pressure, and optimization of host immunity. Despite diagnostic and therapeutic advances, cryptococcosis continues to be a disease with unacceptably high incidence and mortality, particularly in resource-limited settings.

Outcomes in Previously Healthy Cryptococcal Meningoencephalitis Patients treated with Pulse - Taper Corticosteroids for Post-infectious Inflammatory Syndrome

BACKGROUND

Cryptococcal meningoencephalitis (CM) is a major cause of mortality in immunosuppressed patients and previously healthy individuals. In the latter, a post-infectious inflammatory response syndrome (PIIRS) is associated with poor clinical response despite antifungal therapy and negative CSF cultures. Data on effective treatment are limited.

METHODS

Between March 2015 and March 2020, 15 consecutive previously healthy patients with CM and PIIRS were treated with adjunctive pulse corticosteroid taper therapy (PCT) consisting of intravenous methylprednisolone 1 gm daily for 1 week followed by oral prednisone 1 mg/kg/d, tapered based on clinical and radiological response plus oral fluconazole. Montreal Cognitive Assessments (MOCA), Karnofsky Performance scores, MRI brain scanning, ophthalmic and audiologic exams, CSF parameters including cellular and soluble immune responses were compared at PIIRS diagnosis and after methylprednisolone completion.

RESULTS

The median time from antifungal treatment to steroid initiation was 6 weeks. The most common symptoms at PIIRS diagnosis were altered mental status and vision changes. All patients demonstrated significant improvements in MOCA and Karnofsky scores at 1 month (p<0.0003), which was accompanied by improvements in CSF glucose, WBC, protein, cellular and soluble inflammatory markers 1 week after receiving corticosteroids (CS) (p<0.003). All patients with papilledema and visual field deficits also exhibited improvement (p<0.0005). Five out of 7 patients who underwent audiological testing demonstrated hearing improvement. Brain MRI showed significant improvement of radiological findings (p=0.001). CSF cultures remained negative.

CONCLUSIONS

PCT in this small cohort of PIIRS was associated with improvements in CM-related complications with minimal toxicity in the acute setting.

Association of immune checkpoint inhibitors with respiratory infections: A review

Treatment with immune-checkpoint inhibitors (ICIs) has shown efficacy against a variety of cancer types. The use of anti PD-1, anti PD-L1, and anti CTLA-4 antibodies is rapidly expanding. The side effects of ICIs are very different from conventional cytocidal anticancer and molecular target drugs, and may extend to the digestive organs, respiratory organs, thyroid gland, pituitary gland, skin, and others. Although the details of these adverse events are becoming increasingly apparent, much is unknown regarding the effects and adverse events related to infections. This review focuses specifically on the impact of ICIs on respiratory infections. The impact of ICIs on pathogens varies depending on the significance of the role of T-cell immunity in the immune response to the specific pathogen, as well as the different modes of infection (i.e., acute or chronic), although the impact of ICIs on the clinical outcome of infections in humans has not yet been well studied. Enhanced clearance of many pathogens has been shown because immune checkpoint inhibition activates T cells. In contrast, reactivation of tuberculosis associated with ICI use has been reported, and therefore caution is warranted. In COVID-19 pneumonia, ICI administration may lead to exacerbation; however, it is also possible that ICI may be used for the treatment of COVID-19. It has also been shown that ICI has potential in the treatment of intractable filamentous fungal infections. Therefore, expanded clinical applications are expected.

Checkpoint Inhibition and Infectious Diseases: A Good Thing?

The mammalian immune system has evolved the capacity to detect and destroy tumor cells. Tumors utilize multiple strategies to evade host immune surveillance, including the induction of the checkpoint molecules cytotoxic T lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1) to suppress antitumor immunity. Pharmacologic blockade of these molecules with checkpoint inhibitors (CPIs) restores T cell function and prolongs survival in patients with various malignancies. Emerging evidence suggests that the same checkpoint pathways may play a crucial role during infections. Indeed, CPIs appear promising as immunotherapeutic agents in infectious diseases, although their efficacy varies depending on pathogen-, cell-, and organ-specific factors. More research will be necessary to clarify the effects and safety of CPIs on clinically relevant outcomes of human infection.

Clinical Aspects of Immune Damage in Cryptococcosis

Purpose of review

To perform an extensive review of recent literature and provide an update on the current epidemiology, clinical features and management of cryptococcal disease with a focus on the differences between patients depending on their immune status.

Recent findings

Emerging literature has highlighted the inflammatory pathophysiology and varied manifestations of cryptococcal infections in patients who are apparently healthy but paradoxically have a more critical clinical course compared to their immunosuppressed counterparts.

Summary

Non-HIV cryptococcal meningitis has greater mortality compared to that seen in HIV patients. Basic science experiments closely analyzing the underlying pathophysiological response to this infection have demonstrated the predominant role of T cell-mediated inflammatory injury in causing worse clinical outcomes. Further studies are needed to define the need for immunosuppressive agents in the treatment of this illness.