Fatal hemophagocytic lymphohistiocytosis with intravascular large B-cell lymphoma following coronavirus disease 2019 vaccination in a patient with systemic lupus erythematosus: an intertwined case.

Hemophagocytic lymphohistiocytosis (HLH) has been recognized as a rare adverse event following the coronavirus disease 2019 (COVID-19) vaccination. We report a case of neuropsychiatric symptoms and refractory HLH in a woman with systemic lupus erythematosus (SLE) after receiving her COVID-19 vaccine treated with belimumab, later found to have intravascular large B-cell lymphoma (IVLBCL) at autopsy. A 61-year-old woman with SLE was referred to our hospital because of impaired consciousness and fever. One month prior to consulting, she received her second COVID-19 vaccine dose. Afterward, her consciousness level decreased, and she developed a high fever. She tested negative for SARS-CoV-2. Neuropsychiatric SLE was suspected; therefore, glucocorticoid pulse therapy was initiated on day 1 and 8. She had thrombocytopenia, increased serum ferritin levels and hemophagocytosis. The patient was diagnosed with HLH and treated with etoposide, dexamethasone and cyclosporine. Despite treatment, the patient died on day 75; autopsy report findings suggested IVLBCL as the underlying cause of HLH. Differentiating comorbid conditions remains difficult; however, in the case of an atypical clinical presentation, other causes should be considered. Therefore, we speculate that the COVID-19 vaccination and her autoimmune condition may have expedited IVLBCL development.

Prognostic impacts of serum levels of C-reactive protein, albumin, and total cholesterol in patients with myelodysplastic syndromes.

Various systems for predicting the prognosis of patients with myelodysplastic syndromes (MDS) have been developed. However, associations between performance status (PS) and prognosis of MDS require further investigation. To objectively assess the impact of PS on survival, we examined laboratory findings associated with PS, including serum levels of C-reactive protein (CRP), albumin (ALB), and total cholesterol (CHOL). Patients (n = 123; male 86, female 37; median age 74 yrs.) diagnosed with MDS or myelodysplastic/myeloproliferative neoplasms at Kanazawa Medical University Hospital between 2010 and 2020 were enrolled and grouped by cutoff values determined by receiver operating characteristic analysis: 0.44 mg/dL for CRP, 4.0 g/dL for ALB, and 120 mg/dL for CHOL. The median follow-up period was 17.6 months. Kaplan-Meier analysis revealed that overall survival (OS) in the high CRP, low ALB, and low CHOL groups was significantly shorter than in the low CRP, high ALB, and high CHOL groups, respectively. Multivariable analysis revealed that elevated serum CRP was an independent prognostic risk factor independent of gender, bone marrow blast percentage, and cytogenetics.

Comprehensive analysis of protein-expression changes specific to immunoglobulin G4-related disease.

BACKGROUND AND AIMS: Immunoglobulin 4 (IgG4)-related disease (IgG4-RD) is a lymphoproliferative disorder characterized by elevated serum IgG4 levels and tissue infiltration of IgG4-positive plasma cells. We analyzed the serum proteins, whose levels varied based on the disease state and treatment. MATERIALS AND METHODS: Serum proteins from patients with IgG4-related disease and healthy subjects were resolved using two-dimensional electrophoresis, silver-stained, and scanned. Alternatively, the proteins were labeled with Cy2, Cy3, and Cy5 before electrophoresis. The proteins, whose expression differed significantly between patients and healthy individuals, and between before and after steroid treatment, were identified and validated using enzyme-linked immunosorbent assays. RESULTS: Pre-treatment sera from patients with IgG4-related disease was characterized by increased levels of immunoglobulins such as IgG1, IgG4; inflammatory factors such as α-1 antitrypsin (A1AT); and proteins associated with immune system regulation such as clusterin and leucine-rich α-2-glycoprotein (LRG-1). The serum levels of A1AT, LRG-1 and clusterin, during treatment with prednisolone for up to 12 months revealed that LRG-1 levels were halved after 1 month of treatment, comparable to those in healthy subjects; LRG-1 levels remained normal until the end of treatment. CONCLUSION: LRG-1 could serve as a novel biomarker of IgG4-related diseases.

Impaired expression of innate immunity-related genes in IgG4-related disease: A possible mechanism in the pathogenesis of IgG4-RD.

Background: IgG4-related disease (IgG4-RD) is characterized by elevated serum IgG4 and tissue infiltration by IgG4-positive plasma cells. The pathogenesis of this disease is not clear. Transcriptome analysis was performed to identify genes over- and under-expressed in patients with IgG4-RD.Method: DNA microarray analysis was performed using RNA from peripheral blood mononuclear cells of two patients with IgG4-RD and four healthy individuals. Genes showing a greater than threefold change in expression in IgG4-RD patients following steroid therapy were identified. Four genes related to innate immunity such as transcobalamin I (TCN1), secretory leukocyte peptidase inhibitor (SLPI), bactericidal/permeability-increasing protein (BPI) and lactotransferrin (LTF) were assessed by real-time PCR in 15 IgG4-RD patients and 13 healthy individuals.Result: DNA microarray analysis identified 30 genes showing a greater than threefold change in expression in IgG4-RD patients following steroid therapy. Real-time RT-PCR showed that the levels of mRNAs encoding TCNI and SLPI, except for BPI and LTF, were significantly lower in patients with IgG4-RD than in healthy people. The levels of all four mRNAs in patients with IgG4-RD were significantly increased after steroid treatment.Conclusion: These results indicate that reduction in expression of innate immunity-related genes may participate in the pathogenesis of IgG4-RD that steroid treatment may rectify impaired innate immunity as well as acquired immunity.

Osteosarcoma Manifesting Systemic Inflammation and Histological Features Mimicking Plasma Cell-type Castleman Disease.

A 73-year-old man was referred to our hospital with a persistent fever, anemia, and a mass in the left pubic region. The findings of biopsy evaluations of the mass and a left inguinal lymph node were consistent with Castleman disease (CD) of plasma cell type. His serum interleukin 6 (IL-6) level was remarkably elevated, supporting the diagnosis of CD. However, imaging analyses revealed destruction of the pubic bone by the mass, which was atypical for CD. Therefore, another deeper biopsy was performed, which finally led to the diagnosis of IL-6-producing osteosarcoma. We conclude that clinicians should carefully exclude malignancies prior to making a CD diagnosis.

Is TAFRO syndrome a subtype of idiopathic multicentric Castleman disease?

Castleman disease (CD) is a rare lymphoproliferative disorder that can be unicentric or multicentric. Multicentric CD (MCD) is further subdivided into human herpesvirus type-8-associated, POEMS syndrome-associated, and idiopathic (iMCD). TAFRO syndrome is a newly identified disorder of unknown etiology characterized by thrombocytopenia, anasarca, fever, reticulin myelofibrosis, renal dysfunction, and organomegaly. The TAFRO syndrome is sometimes regarded as a subtype of iMCD (TAFRO-iMCD), whereas iMCD without TAFRO syndrome is considered "not otherwise specified" (iMCD-NOS). However, a proportion of patients with TAFRO syndrome have been diagnosed without lymph node biopsies (TAFRO syndrome without proven iMCD; TAFRO-w/op-iMCD). To clarify the clinical features of iMCD-NOS, TAFRO-iMCD, and TAFRO-w/op-iMCD, we retrospectively analyzed 220 patients extracted from the database of the Multicenter Collaborative Retrospective Study for Establishing the Concept of TAFRO Syndrome. The patients included 87 with iMCD-NOS, 63 with TAFRO-iMCD, and 19 with TAFRO-w/op-iMCD. Patients in all three groups exhibited anemia, hypoalbuminemia, and elevated serum C-reactive protein and interleukin-6 levels. No significant differences in clinical, laboratory, and prognostic features were noted between the TAFRO-iMCD, and TAFRO-w/op-iMCD groups. However, the iMCD-NOS group exhibited polyclonal hyper-γ-globulinemia. The five-year survival rates of patients in the iMCD-NOS and TAFRO-involved groups were 100% and 66.5%, respectively (dropping markedly during the first few months in the latter). The iMCD-NOS and the TAFRO-iMCD samples typically showed plasma cell and mixed-type histologies, respectively. Thus, iMCD can be classified into two distinct subtypes, iMCD-NOS and TAFRO-iMCD. As such, TAFRO-iMCD and TAFRO-w/op-iMCD may be considered the same entity, requiring prompt diagnosis and intensive care.

A multicenter phase II prospective clinical trial of glucocorticoid for patients with untreated IgG4-related disease.

OBJECTIVE: Although glucocorticoids are effective for patients with IgG4-related disease, the treatment has not yet been standardized. Therefore, the treatment strategy should be established. PATIENTS AND METHODS: Patients who fulfilled the comprehensive diagnostic criteria for definite IgG4-related disease were started on prednisolone (0.6 mg/kg body weight) with the dose reduced every two weeks. The subsequent maintenance dose and need for prednisolone were determined for individual patients. The primary endpoint was the complete remission (CR) rate at one year. Secondary endpoints included overall response rate (ORR), the maintenance dose, the relapse rate, and adverse events. RESULTS: This study enrolled 61 patients. After clinicopathological review, three patients were excluded, and one, 13, and 44 patients were diagnosed with probable, possible, and definite IgG4-related disease, respectively. Of the 44 patients with definite IgG4-RD, 29 (65.9%) achieved CR, and the ORR was 93.2%. No patient was refractory to primary treatment. The most frequent adverse events were glucose intolerance. Six patients relapsed. CONCLUSIONS: Glucocorticoid treatment is usually effective for patients with IgG4-RD, and we should examine the possibility of other disorders when a patient is glucocorticoid refractory. Some patients are misdiagnosed, making central clinicopathological review of diagnosis very important in conducting clinical studies.

Sjögren's syndrome manifesting as clinicopathological features of TAFRO syndrome: A case report.

RATIONALE: TAFRO syndrome is a newly proposed disorder that manifests as thrombocytopenia, anasarca, fever, reticulin myelofibrosis, renal dysfunction, and organomegaly. In this report, we describe the development of severe TAFRO syndrome-like systemic symptoms during the clinical course of juvenile-onset Sjögren's syndrome in a 32-year-old woman. PATIENT CONCERNS: The patient was admitted due to dyspnea, fever, polyarthralgia, and generalized edema. She had been diagnosed with Sjögren's syndrome at the age of 14 years, based on histopathological examination of a biopsy of the minor salivary glands and the development of Raynaud's phenomenon, with no follow-up treatment required. On admission, she presented with anemia, elevated C-reactive protein levels, anasarca, and hepato-splenomegaly. A bone marrow examination revealed increased megakaryocytes with reticulin fibrosis, and the histopathology of an axillary lymph node was consistent with mixed-type Castleman disease. Eventually, she developed thrombocytopenia. INTERVENTIONS: Her symptoms fulfilled all of the major and minor categories of the diagnostic criteria for TAFRO syndrome. However, considering her prior diagnosis, we assumed that the clinical presentation was consistent with an acute exacerbation of Sjögren's syndrome. Unlike typical cases of TAFRO syndrome, the administration of relatively low-dose prednisolone relieved her symptoms. LESSONS: Differentiation between TAFRO syndrome and exacerbation of an autoimmune disease is clinically important, although this can be challenging. Identification of specific biomarkers for TAFRO syndrome would be clinically beneficial.

Proposed diagnostic criteria, disease severity classification and treatment strategy for TAFRO syndrome, 2015 version.

TAFRO syndrome is a systemic inflammatory disorder characterized by thrombocytopenia, anasarca including pleural effusion and ascites, fever, renal insufficiency, and organomegaly including hepatosplenomegaly and lymphadenopathy. Its onset may be acute or sub-acute, but its etiology is undetermined. Although several clinical and pathological characteristics of TAFRO syndrome resemble those of multicentric Castleman disease (MCD), other specific features can differentiate between them. Some TAFRO syndrome patients have been successfully treated with glucocorticoids and/or immunosuppressants, including cyclosporin A, tocilizumab and rituximab, whereas others are refractory to treatment, and eventually succumb to the disease. Early and reliable diagnoses and early treatments with appropriate agents are essential to enhancing patient survival. The present article reports the 2015 updated diagnostic criteria, disease severity classification and treatment strategy for TAFRO syndrome, as formulated by Japanese research teams. These criteria and classification have been applied and retrospectively validated on clinicopathologic data of 28 patients with this and similar conditions (e.g. MCD with serositis and thrombocytopenia).

Isolation of vascular smooth muscle antigen-reactive CD4(+)αßTh1 clones that induce pulmonary vasculitis in MRL/Mp-Fas(+/+) mice.

Here, we established CD4(+)αßTh1 clones specific for rat vascular smooth muscle antigen (VSMAg) that induced vasculitis lesions in the lungs of MRL/Mp-Fas(+/+) mice following adoptive transfer. Six different T cell clones, MV1b1 (Vß1), MV1b4 (Vß4), MV1b8.3 (Vß8.3), MV1b61 (Vß6), MV1b62 (Vß6), and MV1b63 (Vß6), were isolated from the MV1 T cell line from the regional lymph nodes of immunized MRL/Mp-Fas(+/+) mice; the three (Vß6) clones had unique CDR3 amino acid sequences. Following stimulation with VSMAg-pulsed antigen presenting cells, MV1b61 and MV1b62 failed to secrete interferon-γ and tumor necrosis factor-α, although the other four clones secreted high levels of both cytokines. In adoptive transfer experiments, MV1b61 and MV1b62 did not induce organ involvement including pulmonary vasculitis. In contrast, MV1b1, MV1b4, MV1b8.3, and MV1b63 induced perivascular mononuclear cell infiltration in pulmonary small arteries. These clones may provide useful tools for investigating the underlying mechanisms of vasculitis syndromes and for developing therapeutic strategies.

Prospective clinical study of R-CMD therapy for indolent B cell lymphoma and mantle cell lymphoma from the Hokuriku Hematology Oncology Study Group.

Standardized treatments for indolent B cell lymphoma primarily consisting of follicular lymphoma (FL) and for mantle cell lymphoma (MCL) have yet to be established. Here the Hokuriku Hematology Oncology Study Group conducted a multicenter prospective study to investigate the efficacy and safety of a combination regimen of rituximab, cladribine, mitoxantrone, and dexamethasone (R-CMD) in indolent B cell lymphoma and MCL. A total of 33 CD20-positive patients who received care between January 2008 and August 2011 were investigated. These patients' illnesses were FL (n = 21), nodal marginal zone B cell lymphoma (NMZB, n = 3), MCL (n = 3), splenic marginal zone B cell lymphoma (n = 2), hairy cell leukemia (n = 1), Waldenstrom macroglobulinemia (WM, n = 1), and lymphoplasmacytic lymphoma (LPL, n = 2). Patients received four 21-day cycles of rituximab 375 mg/m(2) (day 1), cladribine 0.10 mg/kg (days 1-3), mitoxantrone 8 mg/m(2) (day 1), and dexamethasone 8 mg/body (days 1-3), with four additional rituximab doses at 4-week intervals. Of the 33 patients, 26 achieved complete response/unconfirmed complete response, and six achieved a partial response (4 with FL, 1 with NMZB, 1 with WM). One had progressive disease (FL), and four relapsed after remission (1 with FL, 2 with MCL, 1 with LPL). R-CMD therapy was relatively convenient and effective in indolent B cell lymphoma and MCL. Nonetheless, to suppress the number and function of both B cells and T cells, comprehensive infection prevention and follow-up are necessary in the future.

Decreased Expression of Innate Immunity-Related Genes in Peripheral Blood Mononuclear Cells from Patients with IgG4-Related Disease.

BACKGROUND: IgG4-related disease (IgG4-RD) is a new clinical entity of unknown etiology characterized by elevated serum IgG4 and tissue infiltration by IgG4-positive plasma cells. Although aberrancies in acquired immune system functions, including increases in Th2 and Treg cytokines observed in patients with IgG4-RD, its true etiology remains unclear. To investigate the pathogenesis of IgG4-RD, this study compared the expression of genes related to innate immunity in patients with IgG4-RD and healthy controls. MATERIALS AND METHODS: Peripheral blood mononuclear cells (PBMCs) were obtained from patients with IgG4-RD before and after steroid therapy and from healthy controls. Total RNA was extracted and DNA microarray analysis was performed in two IgG4-RD patients to screen for genes showing changes in expression. Candidate genes were validated by real-time RT-PCR in 27 patients with IgG4-RD and 13 healthy controls. RESULTS: DNA microarray analysis identified 21 genes that showed a greater than 3-fold difference in expression between IgG4-RD patients and healthy controls and 30 genes that showed a greater than 3-fold change in IgG4-RD patients following steroid therapy. Candidate genes related to innate immunity, including those encoding Charcot-Leyden crystal protein (CLC), membrane-spanning 4-domain subfamily A member 3 (MS4A3), defensin alpha (DEFA) 3 and 4, and interleukin-8 receptors (IL8R), were validated by real-time RT-PCR. Expression of all genes was significantly lower in IgG4-RD patients than in healthy controls. Steroid therapy significantly increased the expression of DEFA3, DEFA4 and MS4A3, but had no effect on the expression of CLC, IL8RA and IL8RB. CONCLUSIONS: The expression of genes related to allergy or innate immunity, including CLC, MS4A3, DEFA3, DEFA4, IL8RA and IL8RB, was lower in PBMCs from patients with IgG4-RD than from healthy controls. Although there is the limitation in the number of patients applied in DNA microarray, impaired expression of genes related to innate immunity may be involved in the pathogenesis of IgG4-RD as well as in abnormalities of acquired immunity.

CD14+ follicular dendritic cells in lymphoid follicles may play a role in the pathogenesis of IgG4-related disease.

Proliferated IgG4(+) plasma cells are polyclonal, suggesting that the pathogenesis of IgG4-related disease (IgG4-RD) involves upstream events related to the regulation of IgG4 expansion. We hypothesized that lymphoid follicle formation may play an important role in the pathogenesis of IgG4-RD. Using various antibodies, especially against monocyte, macrophage, and follicular dendritic cell markers, we immunohistochemically assessed the distribution of immune cells in lymphoid follicles. Pathological findings of tissue samples from patients with IgG4-RD (n = 22), reactive hyperplasia (n = 3), multicentric Castleman's disease (n = 3), and Sjögren's syndrome (n = 13) were analyzed. CD14-positive lymphoid follicles were observed only in patients with IgG4-RD, and CD14-positive cells were identified as follicular dendritic cells by multicolor immunohistochemistry. There were few differences in the distributions of other cell types between the IgG4-RD and control groups. The presence of CD14(+) follicular dendritic cells in lymphoid follicles may play a pathophysiological role in IgG4-RD.

IgG4-related disease: diagnostic methods and therapeutic strategies in Japan.

This review describes methods utilized in Japan to diagnose and treat patients with IgG4-related disease. A diagnosis of IgG4-related disease is based on elevated serum IgG4 concentration and an increased number of IgG4(+) plasma cells. Differentiating IgG4-related disease from other disorders, especially malignancy, is quite important. Consensus treatment in Japan consists of an initial dose of prednisolone at 0.5-0.6 mg/kg/day, followed by careful and gradual dose reduction. Most patients require maintenance treatment at 5 to 10 mg/day. Patients refractory to glucocorticoids are either truly refractory or have been misdiagnosed, therefore requiring reassessment.

IgG4-related disease and its pathogenesis-cross-talk between innate and acquired immunity.

IgG4-related disease (IgG4-RD) is a novel clinical entity proposed in Japan in the 21th century and is attracting strong attention over the world. The characteristic manifestations of IgG4-RD are increased serum IgG4 concentration and tumefaction by IgG4(+) plasma cells. Although the clinical manifestations in various organs have been established, the pathogenesis of IgG4-RD is still unknown. Recently, many reports of aberrant acquired immunity such as Th2-diminated immune responses have been published. However, many questions still remain, including questions about the pathogenesis of IgG4-RD and the roles of IgG4. In this review, we discuss the pathogenesis of IgG4-RD by focusing on the cross-talk between innate and acquired immunity.

Long-term heat exposure prevents hypoxia-induced apoptosis in mouse fibroblast cells.

Long-term continuous exposure to high ambient temperatures induces complete heat acclimation in humans and animals. However, to date, the effects of long-term exposure to heat stress on cells have not been fully evaluated. In this study, we investigated an adaptive physiological process induced in culture cells by continuous exposure to mild heat stress for 60 days. The results of this investigation provide evidence that after long-term heat acclimation in cells, (1) heat shock protein levels are increased, (2) hypoxia inducible factor-1α (HIF-1α) expression is upregulated, and (3) heat shock-induced and hypoxia-induced apoptoses are attenuated. These results suggest that the hypoxia response pathway is an intrinsic part of the heat acclimation repertoire and that the HIF-1 pathway following long-term heat acclimation induces cells with cross tolerance against hypoxia.

Deficient leptin signaling ameliorates systemic lupus erythematosus lesions in MRL/Mp-Fas lpr mice.

Leptin is secreted by adipocytes, the placenta, and the stomach. It not only controls appetite through leptin receptors in the hypothalamus, it also regulates immunity. In the current study, we produced leptin-deficient MRL/Mp-Fas(lpr) mice to investigate the potential role of leptin in autoimmunity. C57BL/6J-ob/ob mice were backcrossed with MRL/Mp-Fas(lpr) mice, which develop human systemic lupus erythematosus (SLE)-like lesions. The effects of leptin deficiency on various SLE-like manifestations were investigated in MRL/Mp-Fas(lpr) mice. The regulatory T cell population in the spleen was analyzed by flow cytometry, and the effects of leptin on regulatory T cells and Th17 cells were evaluated in vitro. Compared with leptin-producing MRL/Mp-Fas(lpr) mice, leptin-deficient MRL/Mp-Fas(lpr) mice showed less marked splenomegaly and a particularly low population of CD3(+)CD4(-)CD8(-)B220(+) T cells (lpr cells). Their serum concentrations of Abs to dsDNA were lower, and renal histological changes at age 20 wk were ameliorated. Regulatory T cells were increased in the spleens of leptin-deficient MRL/Mp-Fas(lpr) mice. Leptin suppressed regulatory T cells and enhanced Th17 cells in vitro. In conclusion, blockade of leptin signaling may be of therapeutic benefit in patients with SLE and other autoimmune diseases.

Upregulation of aquaporin expression in the salivary glands of heat-acclimated rats.

It is known that aquaporin (AQP) 5 expression in the apical membrane of acinar cells in salivary glands is important for the secretion of saliva in rodents and humans. Although heat acclimation enhances saliva secretion in rodents, the molecular mechanism of how heat induces saliva secretion has not been determined. Here, we found that heat acclimation enhanced the expression of AQP5 and AQP1 in rat submandibular glands concomitant with the promotion of the HIF-1α pathway, leading to VEGF induction and CD31-positive angiogenesis. The apical membrane distribution of AQP5 in serous acinar cells enhanced after heat acclimation, while AQP1 expression was restricted to the endothelial cells in the submandibular glands. A network of AQPs may be involved in heat-acclimated regulation in saliva secretion. Because AQPs probably plays a crucial role in saliva secretion in humans, these findings may lead to a novel strategy for treating saliva hyposecretion.

Japanese variant of multicentric castleman's disease associated with serositis and thrombocytopenia--a report of two cases: is TAFRO syndrome (Castleman- Kojima disease) a distinct clinicopathological entity?

Multicentric Castleman's disease (MCD) is a polyclonal lymphoproliferative disorder that manifests as marked hyper-γ-globulinemia, severe inflammation, anemia, and thrombocytosis. Recently, Takai et al. reported a new disease concept, TAFRO syndrome, named from thrombocytopenia, anasarca, fever, reticulin fibrosis, and organomegaly. Furthermore, Kojima et al. reported Japanese MCD cases with effusion and thrombocytopenia (Castleman-Kojima disease). Here, we report two cases of MCD associated with marked pleural effusion, ascites, and thrombocytopenia, and discuss the independence of the TAFRO syndrome (Castleman-Kojima disease). Case 1: A 57-year-old woman had fever, anemia, anasarca, and some small cervical lymphadenopathy. Although she had been administered steroid therapy, and full-coverage antibiotics, her general condition, including fever, systemic inflammation, and anasarca, deteriorated steadily. We administered chemotherapy [CHOEP (cyclophosphamide, doxorubicin, vincristine, etoposide, and prednisolone) regimen], but despite a transient improvement, she died due to septic shock. Case 2: A 73-year-old man with a history of aplastic anemia and remission presented with fever, severe inflammation, and anasarca. Prednisolone was administered (15 mg daily), and his hyperinflammation once improved. Nevertheless, his general condition, including pleural effusion and ascites, worsened, and C-reactive protein and interleukin-6 levels showed marked increases. The patient died due to multiorgan failure. Cases of TAFRO syndrome (Castleman-Kojima disease) are still rare. Therefore, it is necessary to conduct multicenter clinical surveys including similar cases, such as ours, to reach a consensus regarding diagnostic criteria, therapeutic strategy, and pathophysiological etiology for this syndrome.