TEMPI syndrome: A clinical, light-microscopic and phenotypic evaluation with review of the literature.

BACKGROUND AND OBJECTIVES: TEMPI (telangiectasias, elevated erythropoietin and erythrocytosis, monoclonal gammopathy, perinephric fluid collections, and intrapulmonaryshunting) syndrome is a rare multisystemic disease classified as a monoclonal gammopathy of cutaneous significance. The pathogenesis and etiology of TEMPIare not well known because of the rarity of this disorder. Although telangiectasias are the hallmark of this syndrome, skin biopsies are rarely performed. We aim to further characterize TEMPI syndrome through the evaluationof a skin biopsy. METHODS: We reviewed the histopathology and immunophenotypic profile of a skin biopsy from a 53-year-oldwoman diagnosed with TEMPI syndrome. Other components of her syndromic complex included an IgA myeloma, elevated vascular endothelial growth factor (VEGF), and erythrocytosis. RESULTS: A biopsy showed prominent vascular ectasia with some degree of microvascular basement membranezone thickening. Our patient had a reduction in neoplastic plasma cell burdenand clearing of her telangiectasias following myeloma directed treatment. CONCLUSIONS: TEMPI can beviewed as a reactive vascular paraneoplastic syndrome in the setting of a plasma cell dyscrasia. Elaboration of VEGF from neoplastic plasma cells is likely pathogenetically implicated and appears to be a common link that explains other vascular lesions associated with monoclonal gammopathy syndromes.

Febrile Ulceronecrotic Mucha-Habermann Disease Associated With Hemophagocytic Lymphohistiocytosis: A Case Report and Review of the Literature.

ABSTRACT: Mucha-Habermann disease (MHD) is an inflammatory skin disease characterized by polymorphous eruptions of erythematous, necrotic macules that have been reported for similarities to cutaneous T-cell lymphoma. Febrile ulceronecrotic MHD (FUMHD) represents a severe variant of MHD, marked by ulcers, hemorrhagic bullae, and systemic symptoms. Herein, we report a case of a severely atypical lymphomatoid expression of FUMHD associated with hemophagocytic lymphohistiocytosis (HLH). A previously healthy 21-year-old woman was admitted to the hospital with a rapidly progressive necrotic papular rash. Physical examination revealed right orbital swelling, bilateral hemorrhagic auricular bullae, and multiple ulcerative purpuric papulonodules on the trunk, face, and extremities. Biopsy indicated a dermal and subcutaneous infiltrate of atypical CD8 + lymphocytes with loss of CD5 and reduction in CD7 expression, along with features of lymphomatoid vasculitis. A diagnosis of a severely atypical lymphomatoid expression of FUMHD was made. The patient also met 7 of 9 HLH-2004 criteria, leading to a diagnosis of HLH. Positron emission tomography/computed tomography, flow cytometry, and rheumatologic workup were unremarkable. Treatment with an eight-week course of etoposide and dexamethasone for HLH led to rapid clinical improvement. Over time, her skin lesions regressed and eventually scabbed over to leave hyperpigmented scars, confirming the diagnosis of MHD. She has remained stable, off therapy for 4 years. Although potentially fatal, FUMHD often exhibits favorable outcomes and may resolve without recurrence, as in our patient. FUMHD should be considered in the differential diagnosis for patients presenting with cutaneous CD8 + necrotizing angiocentric lymphoproliferative disease complicated by HLH.

Premortem Skin Biopsy Assessing Microthrombi, Interferon Type I Antiviral and Regulatory Proteins, and Complement Deposition Correlates with Coronavirus Disease 2019 Clinical Stage.

Apart from autopsy, tissue correlates of coronavirus disease 2019 (COVID-19) clinical stage are lacking. In the current study, cutaneous punch biopsy specimens of 15 individuals with severe/critical COVID-19 and six with mild/moderate COVID-19 were examined. Evidence for arterial and venous microthrombi, deposition of C5b-9 and MASP2 (representative of alternative and lectin complement pathways, respectively), and differential expression of interferon type I-driven antiviral protein MxA (myxovirus resistance A) versus SIN3A, a promoter of interferon type I-based proinflammatory signaling, were assessed. Control subjects included nine patients with sepsis-related acute respiratory distress syndrome (ARDS) and/or acute kidney injury (AKI) pre-COVID-19. Microthrombi were detected in 13 (87%) of 15 patients with severe/critical COVID-19 versus zero of six patients with mild/moderate COVID-19 (P < 0.001) and none of the nine patients with pre-COVID-19 ARDS/AKI (P < 0.001). Cells lining the microvasculature staining for spike protein of severe acute respiratory syndrome coronavirus 2, the etiologic agent of COVID-19, also expressed tissue factor. C5b-9 deposition occurred in 13 (87%) of 15 patients with severe/critical COVID-19 versus zero of six patients with mild/moderate COVID-19 (P < 0.001) and none of the nine patients with pre-COVID-19 ARDS/AKI (P < 0.001). MASP2 deposition was also restricted to severe/critical COVID-19 cases. MxA expression occurred in all six mild/moderate versus two (15%) of 13 severe/critical cases (P < 0.001) of COVID-19. In contrast, SIN3A was restricted to severe/critical COVID-19 cases co-localizing with severe acute respiratory syndrome coronavirus 2 spike protein. SIN3A was also elevated in plasma of patients with severe/critical COVID-19 versus control subjects (P ≤ 0.02). In conclusion, the study identified premortem tissue correlates of COVID-19 clinical stage using skin. If validated in a longitudinal cohort, this approach could identify individuals at risk for disease progression and enable targeted interventions.

Linear IgA bullous dermatosis in the setting of angioimmunoblastic T-cell lymphoma.

We report an 80-year-old male developing linear IgA bullous dermatosis (LAD) in the setting of angioimmunoblastic T-cell lymphoma (AITL). This phenomenon is rare, as only three cases have been described in the literature. The pathophysiologic process can be attributed to dysregulation in somatic hypermutation and the expression of chemokine receptor 5 in AITL, contributing to increased IgA. Immunoglobulin production resulting from clonal plasma cell expansion may be because of the B-cell promotional effect by neoplastic follicular helper T-cells. Beyond providing a pathophysiologic platform for AITL-associated LAD, we also briefly summarized prior cases. This report demonstrates the importance of considering LAD in the differential diagnosis for patients with a bullous eruption in the setting of AITL.

Azathioprine hypersensitivity syndrome manifesting as subcutaneous Sweet syndrome and acute pancreatitis.

Azathioprine (AZA) is a commonly used immunosuppressive therapy that has been implicated in a number of cutaneous and systemic inflammatory reactions. Initiation of AZA has been associated with a hypersensitivity syndrome manifesting as acute pancreatitis and Sweet syndrome. Subcutaneous Sweet syndrome is a rare variant of Sweet syndrome where the dominant localization of inflammation is within the subcutaneous fat; it is commonly associated with underlying myeloproliferative disease. However, it has not been reported in the literature as a cutaneous manifestation of AZA hypersensitivity syndrome. We present a unique case of acute pancreatitis and biopsy-proven subcutaneous Sweet syndrome following the initiation of AZA with resolution upon discontinuation.

Primary cutaneous blastic marginal zone lymphoma: A comprehensive clinical, light microscopic, phenotypic and cytogenetic appraisal.

BACKGROUND: Primary cutaneous marginal zone lymphoma (PCMZL) is a form of indolent lymphoproliferative disease where the disease is largely a cutaneous confined process. It is typically a neoplasm composed of post germinal small B-cells and light chain restricted plasma cells in a background of reactive T-cell hyperplasia and benign germinal centers. Rarely a significant degree of large cell infiltration occurs warranting the categorization as blastic marginal zone lymphoma. MATERIALS AND METHODS: We reviewed our data base over a time period of 2016 to 2022 for cases diagnosed as blastic MZL. Twelve cases were identified. The clinical records and pathological data were reviewed. RESULTS: Nine of the cases represented de novo forms of blastic MZL while in three cases there was a prior history of MZL. Multifocal cutaneous disease was not uncommon and one quarter of the cases had evidence of extracutaneous dissemination. All patients except three achieved remission with varied therapeutic interventions depending on the extent of the disease ranging from conservative re-excision to chemotherapy. No patient died from lymphoma. Light microscopically, there was evidence of a background of conventional MZL in the majority of cases. The large cell component was typically characterized by multiple micronodular aggregates throughout the dermis although in three cases there was a striking diffuse large cell component as the dominant infiltrate. Phenotypically, a third of the cases showed either CD5 or CD23 positivity amidst neoplastic B cells. Significant staining for BCL-2 was noted in the majority of cases tested while extensive MUM-1 positivity was observed in half of the cases tested. Kappa or lambda light chain restriction was seen in most. The Ki67 proliferation index exceeded 30 % in all cases. There was C-MYC positivity in two cases. While most cases did not detect cytogenetic abnormalities, one case had multiple cytogenetic hits that are associated with diffuse large B cell lymphoma. Next generation sequencing showed a Ten-eleven translocation 2 mutation in the earlier biopsy prior to transformation and in the later biopsy after transformation along with an additional B2M mutation in the transformed biopsy. Both types of mutations are very uncommon but held to contribute to tumor progression in the setting of diffuse large B cell lymphoma. CONCLUSION: Blastic MZL is associated with a more aggressive clinical course. Even when there is disseminated disease patients while not always cured did not have a fatal course in this series. The light microscopic findings are reproducible. The background of MZL, identification of larger cells in significant numbers without a follicle center phenotype, at times expressing CD5 or CD23 with variable positivity for MUM1, BCL-2 and C-MYC and a high proliferation index define the pathology in most. Certain cytogenetic abnormalities and genetic mutations implicated in large cell transformation into a diffuse large B cell lymphoma are seen in blastic MZL with earlier biopsies prior to transformation potentially harboring at risk genetic mutations.

Lichen sclerosus: A C5B-9 mediated chronic microvascular injury syndrome potentially reflective of common adult comorbidities.

Lichen sclerosus (LS) is a cutaneous disease of unknown etiology that often involves the vulva or foreskin but also can affect extragenital sites. Regardless of the anatomic site, the histomorphology and presumably pathogenesis are similar. Perhaps a clue to the pathophysiology of LS lies in its frequent association with morphea, specifically, when occurring in an extragenital context. In our experience a striking feature evident in established lichen sclerosis (LS) is one of superficial vascular drop out whereby residual vessels exhibited endothelial cell necrosis and microvascular basement membrane zone thickening, the latter reflective of antecedent episodes of microvascular injury. We sought to understand the pathophysiology that underlies the distinct vascular changes and in doing so, shed light on the pathogenesis of LS. We examined 44 cases of LS over a period of 2019 to 2021. We were able to obtain past medical histories in 34 of the 44 cases. Regarding pathological assessment, the predominant focus was on microvascular changes. We assessed the role of C5b-9 mediated vascular injury in the pathogenesis of the vasculopathy and enhanced type I interferon signaling in vessels given the morphologic semblance to the select interferonopathy syndromes, namely fibrosing dermatomyositis and Kohlmeier Degos disease. We examined the expression of CMV DNA and protein based on prior observations in an earlier study that isolated early protein expression in the microvasculature in the setting of LS and scleroderma. From a clinical perspective, the most striking association was an older age at the time of diagnosis (mean age of 62 years and median age of 61.5 years) and the presence of vascular comorbidities of diabetes, hypertension, and hyperlipidemia in almost 80% of cases. All cases showed significant microvascular changes in the superficial corium with the most frequent findings being those of significant basement membrane zone reduplication and vascular drop out. A number of cases showed prominent microvascular deposits of C5b-9 in the zone of hyalinizing fibrosis or subjacent to the discernible table of fibroplasia in the absence of enhanced type I interferon signaling. In no case were there viral cytopathic changes associated with CMV affecting the endothelium. The studies that encode CMV DNA or protein did not show a significant role for CMV reactivation in endothelium in the majority of the studied cases. It is concluded that the pathophysiology of LS includes a microvascular injury syndrome within the papillary dermis. The mechanism of endothelial cell injury is complement mediated at least in part and could reflect an adaptive immune response targeting endothelium indicative of classic complement pathway activation when coexisting with morphea or occurring in younger individuals. A non-immune based endothelial dysfunction and complement mediated injury unrelated to antibody driven classic complement pathway activation are more likely pathogenetically in the setting of certain diseases like diabetes mellitus and hypertension. Vascular drop out can be explained by the diminished endothelial progenitor pool needed to repopulate the damaged microvessels in certain settings like hypertension and diabetes.

Cutaneous type IV hypersensitivity reaction following tebentafusp treatment for uveal melanoma.

Tebentafusp is a bispecific protein that recently underwent FDA approval for the treatment of metastatic uveal melanoma that functions by redirecting cytotoxic T cells to glycoprotein-100, a protein highly expressed in melanoma. Although clinical trials have demonstrated that rashes are common in the first few days of treatment, little is known about skin reactions that develop later in the treatment course. Herein, we describe a type IV hypersensitivity reaction and vitiligo-like depigmentation that developed six weeks into treatment and discuss the possible mechanisms underlying these reactions. The type IV hypersensitivity reaction resolved without intervention within seven weeks of onset, suggesting that tebentafusp can be safely continued in select patients who develop this cutaneous reaction.

Cutaneous collagenous vasculopathy: A report of three cases.

Cutaneous collagenous vasculopathy is a rare pauci-inflammatory, superficial, cutaneous vasculopathy characterized by progressive fine-branching telangiectasias clinically, while light microscopically one observes dilated venules and capillaries within the superficial dermis exhibiting excessive Type IV collagen within the vessel wall. We present three cases of collagenous vasculopathy. Two cases were associated with certain autoimmune stigmata, including a positive serologic anti-endothelial cell antibody assay and positive lupus anticoagulant in one, while the third case had positive anti-ribonucleoprotein (RNP) antibodies. The latter case was associated with chronic hydroxyurea therapy for an underlying myeloproliferative disorder. We explore the role of immune- and non-immune-based endothelial cell injury in the pathogenesis of collagenous vasculopathy.

Exploring the pathophysiologic basis of constrictive pericarditis of Kohlmeier Degos disease: A case series and review of the literature.

Kohlmeier-Degos Disease is a unique thrombotic microvascular and arteriopathic vasculopathy that is highly selective in the organs it targets. It invariably involves the skin and can be a purely cutaneous process. It affects both the microvasculature and the arterial system ranging from a thrombogenic microangiopathy to a fibrointimal obliterative arteriopathy with an accompanying background of extravascular fibrosis. A potentially lethal complication of Kohlmeier-Degos disease is constrictive pericarditis and pleuritis. We present three male patients, ages 26 years, 46 years and 58 years of age with established cutaneous and gastrointestinal Kohlmeier-Degos disease who developed progressive pericarditis which in two necessitated a pericardiectomy. There are 6 other reported cases, 5 in men, with restrictive symptoms developing on average 6 years following the onset of skin disease and all with gastrointestinal involvement. Half of the patients died within one year following the diagnosis of cardiopulmonary restrictive disease. The restrictive symptoms developed within 12 months, 2 years and 11 years following the initial skin presentation. In one patient this complication developed despite receiving eculizumab, indicative that this extravascular fibrosing reaction was not complement mediated as opposed to the thrombotic microvascular component of the disease which is C5b-9 mediated. Two of the three patients had evidence of right ventricular dysfunction. Two of our patients died within 1 year of developing constrictive pericarditis due to progressive cardiopulmonary failure. A profibrogenic process resembling scleroderma was seen given the degree of smooth muscle actin staining along with a mirror image reduction in CD34 expression within the fibrotic pleura and pericardium. There was significant upregulation in type I interferon signaling in cases tested as revealed by the degree of staining for MXA, the surrogate type I interferon marker. We propose that excessive type I interferon signaling results in the influx of monocyte derived dendritic cells with subsequent transdifferentiation into potent collagen producing myofibroblasts. We believe that targeting and suppressing type I interferon signaling should be a cornerstone of early therapy in patients with Kohlmeier- Degos disease to prevent pleural and pericardial fibrosis.

Idiopathic systemic capillary leak syndrome, a unique complement and interferon mediated endotheliopathy syndrome: The role of the normal skin biopsy in establishing the diagnosis and elucidating pathogenetic mechanisms.

Idiopathic Systemic Capillary Leak Syndrome (ISCLS), also known as Clarkson's Syndrome, is due to primary fluid and protein leak across capillaries that leads to an accumulation of interstitial fluids and cardiovascular collapse from intravascular hypovolemia. Viral infections are a putative trigger of these episodes. ISCLS is typically associated with a monoclonal gammopathy. Here we present four patients with idiopathic systemic capillary leak syndrome. The cohort consists of three men and one woman who range in age from 55 to 72 years old. All of the patients had a monoclonal gammopathy. Two patients had viral triggers. Biopsies of normal skin were examined throughout all phases of the disease. During an acute attack, we identified perivascular mixed CD4+ and CD8+ T cell lymphocytic infiltrates in the superficial dermis. We observed significant microvascular deposits of C5b-9 and upregulation of type I interferon signaling in endothelium along with reduced serum levels of complement during very active disease. We also identified deposits of immunoglobulin along the dermal epidermal junction mirroring the monoclonal immunoglobulin isotype implicated in each patient. During a post treatment recovery or mild disease phase there was reduced inflammation and decreased amounts of C5b-9 and type I interferon expression. Sudden onset capillary leak syndrome reflects enhanced endothelial cell permeability as a unique form of endothelial injury mediated by the combined effects of complement pathway activation and upregulation of type I interferon signaling on endothelium.

Machine learning integration of scleroderma histology and gene expression identifies fibroblast polarisation as a hallmark of clinical severity and improvement.

OBJECTIVE: We sought to determine histologic and gene expression features of clinical improvement in early diffuse cutaneous systemic sclerosis (dcSSc; scleroderma). METHODS: Fifty-eight forearm biopsies were evaluated from 26 individuals with dcSSc in two clinical trials. Histologic/immunophenotypic assessments of global severity, alpha-smooth muscle actin (aSMA), CD34, collagen, inflammatory infiltrate, follicles and thickness were compared with gene expression and clinical data. Support vector machine learning was performed using scleroderma gene expression subset (normal-like, fibroproliferative, inflammatory) as classifiers and histology scores as inputs. Comparison of w-vector mean absolute weights was used to identify histologic features most predictive of gene expression subset. We then tested for differential gene expression according to histologic severity and compared those with clinical improvement (according to the Combined Response Index in Systemic Sclerosis). RESULTS: aSMA was highest and CD34 lowest in samples with highest local Modified Rodnan Skin Score. CD34 and aSMA changed significantly from baseline to 52 weeks in clinical improvers. CD34 and aSMA were the strongest predictors of gene expression subset, with highest CD34 staining in the normal-like subset (p<0.001) and highest aSMA staining in the inflammatory subset (p=0.016). Analysis of gene expression according to CD34 and aSMA binarised scores identified a 47-gene fibroblast polarisation signature that decreases over time only in improvers (vs non-improvers). Pathway analysis of these genes identified gene expression signatures of inflammatory fibroblasts. CONCLUSION: CD34 and aSMA stains describe distinct fibroblast polarisation states, are associated with gene expression subsets and clinical assessments, and may be useful biomarkers of clinical severity and improvement in dcSSc.

A Covid-19 Patient with Complement-Mediated Coagulopathy and Severe Thrombosis.

We report a patient with severe Covid-19-associated coagulopathy and type 2 diabetes mellitus who tested positive for antiphospholipid antibodies (aPL). Analysis of skin specimens suggested direct SARS-CoV-2 viral-induced and complement-mediated vascular injury and thrombosis, consistent with prior reports. Serial aPL testing demonstrated high levels of anticardiolipin antibodies (aCL) that declined to insignificant levels over a period of 5 weeks. SARS-CoV-2 RNA was detected in nasopharyngeal swab specimens on serial assays performed over the same 5-week period, though it was not detected thereafter. We hypothesize that SARS-CoV-2 viral-induced aPL contributed to severe Covid-19-associated coagulopathy in this patient.

CD8+ Lymphogranulomatous Dermatitis as a Manifestation of Malignancy-Associated Immunodeficiency: Rethinking Paraneoplastic Granulomas.

ABSTRACT: Paraneoplastic granulomatous disease occurs in approximately 7.3% of patients with non-Hodgkin lymphoma, most commonly among patients with chronic lymphocytic leukemia (CLL). These lesions are often reported to appear similar to sarcoidosis in clinical presentation and under light microscopy. However, comprehensive descriptions of the cytomorphologic characteristics of these paraneoplastic granulomas are lacking, and the mechanisms involved in their formation remain ill-defined. Noninfectious dermal granulomatous reactions have also been reported in many primary immunodeficiencies, including common variable immune deficiency and ataxia-telangiectasia. We present a case of noninfectious CD8+ predominant granulomatous dermatitis with ocular involvement occurring in the setting of CLL and marked hypogammaglobulinemia. Based on the analysis of shared factors in patients with primary immunodeficiencies and CLL, we conclude that the presence of pan-humoral immunodeficiency could itself be a risk factor for developing a CD8+ lymphogranulomatous reaction. This report and associated discussion evince that CD8+ predominant granulomatous reactions, distinct from sarcoidosis, may represent a previously unappreciated segment of the paraneoplastic granulomas observed in hematologic malignancies.

Acquired epidermodysplasia verruciformis (AEV) in three children after cardiac transplantation: A case series and review of the literature.

Acquired epidermodysplasia verruciformis (AEV) describes epidermodysplasia verruciformis developing in an immunocompromised host. There is limited information in the literature regarding AEV in the pediatric population; of the patients reported, most patients described had HIV, with only two reported cases of children who developed AEV post-transplantation. This case series describes three pediatric patients who developed AEV on immunosuppressant therapy following cardiac transplantation. We review risk factors, treatment options, and prognosis of AEV in the pediatric population.

A newly described cutaneous reaction at sites of insulin pump use in a child with Type 1 diabetes.

Continuous subcutaneous insulin infusion (CSII), or insulin pumps, with or without continuous glucose monitoring (CGM) devices have become the standard of care for patients with type 1 diabetes. While increasingly popular, a wide range of reported skin reactions to CSII and CGM devices was found. We present this case of a pyogenic granuloma-like neutrophilic and granulomatous response to an insulin pump to increase awareness of a previously uncharacterized cutaneous adverse reaction at insulin pump infusion sites.

Endothelial cell damage is the central part of COVID-19 and a mouse model induced by injection of the S1 subunit of the spike protein.

Neurologic complications of symptomatic COVID-19 are common. Brain tissues from 13 autopsies of people who died of COVID-19 were examined. Cultured endothelial and neuronal cells were incubated with and wild type mice were injected IV with different spike subunits. In situ analyses were used to detect SARS-CoV-2 proteins and the host response. In 13/13 brains from fatal COVID-19, pseudovirions (spike, envelope, and membrane proteins without viral RNA) were present in the endothelia of microvessels ranging from 0 to 14 positive cells/200× field (mean 4.3). The pseudovirions strongly co-localized with caspase-3, ACE2, IL6, TNFα, and C5b-9. The surrounding neurons demonstrated increased NMDAR2 and neuronal NOS plus decreased MFSD2a and SHIP1 proteins. Tail vein injection of the full length S1 spike subunit in mice led to neurologic signs (increased thirst, stressed behavior) not evident in those injected with the S2 subunit. The S1 subunit localized to the endothelia of microvessels in the mice brain and showed co-localization with caspase-3, ACE2, IL6, TNFα, and C5b-9. The surrounding neurons showed increased neuronal NOS and decreased MFSD2a. It is concluded that ACE2+ endothelial damage is a central part of SARS-CoV2 pathology and may be induced by the spike protein alone. Thus, the diagnostic pathologist can use either hematoxylin and eosin stain or immunohistochemistry for caspase 3 and ACE2 to document the endothelial cell damage of COVID-19.

Severe COVID-19: A multifaceted viral vasculopathy syndrome.

The objective of this study was to elucidate the pathophysiology that underlies severe COVID-19 by assessing the histopathology and the in situ detection of infectious SARS-CoV-2 and viral capsid proteins along with the cellular target(s) and host response from twelve autopsies. There were three key findings: 1) high copy infectious virus was limited mostly to the alveolar macrophages and endothelial cells of the septal capillaries; 2) viral spike protein without viral RNA localized to ACE2+ endothelial cells in microvessels that were most abundant in the subcutaneous fat and brain; 3) although both infectious virus and docked viral spike protein was associated with complement activation, only the endocytosed pseudovirions induced a marked up-regulation of the key COVID-19 associated proteins IL6, TNF alpha, IL1 beta, p38, IL8, and caspase 3. Importantly, this microvasculitis was associated with characteristic findings on hematoxylin and eosin examination that included endothelial degeneration and resultant basement membrane zone disruption and reduplication. It is concluded that serious COVID-19 infection has two distinct mechanisms: 1) a microangiopathy of pulmonary capillaries associated with a high infectious viral load where endothelial cell death releases pseudovirions into the circulation, and 2) the pseudovirions dock on ACE2+ endothelial cells most prevalent in the skin/subcutaneous fat and brain that activates the complement pathway/coagulation cascade resulting in a systemic procoagulant state as well as the expression of cytokines that produce the cytokine storm. The data predicts a favorable response to therapies based on either removal of circulating viral proteins and/or blunting of the endothelial-induced response.

Anti-complement C5 therapy with eculizumab in three cases of critical COVID-19.

Respiratory failure and acute kidney injury (AKI) are associated with high mortality in SARS-CoV-2-associated Coronavirus disease 2019 (COVID-19). These manifestations are linked to a hypercoaguable, pro-inflammatory state with persistent, systemic complement activation. Three critical COVID-19 patients recalcitrant to multiple interventions had skin biopsies documenting deposition of the terminal complement component C5b-9, the lectin complement pathway enzyme MASP2, and C4d in microvascular endothelium. Administration of anti-C5 monoclonal antibody eculizumab led to a marked decline in D-dimers and neutrophil counts in all three cases, and normalization of liver functions and creatinine in two. One patient with severe heart failure and AKI had a complete remission. The other two individuals had partial remissions, one with resolution of his AKI but ultimately succumbing to respiratory failure, and another with a significant decline in FiO2 requirements, but persistent renal failure. In conclusion, anti-complement therapy may be beneficial in at least some patients with critical COVID-19.

Eosinophilic Fasciitis Following Checkpoint Inhibitor Therapy: Four Cases and a Review of Literature.

BACKGROUND: Checkpoint inhibitor therapy is widely known to cause a number of immune-related adverse events. One rare adverse effect that is emerging is eosinophilic fasciitis, a fibrosing disorder causing inflammatory infiltration of subcutaneous fascia. It is characterized clinically by edema and subsequent induration and tightening of the skin and subcutaneous tissues. The condition is rare, yet at our institutions we have seen four cases in the past 3 years. We describe our 4 cases and review 11 other cases reported in the literature. CASE PRESENTATION: We present four cases of eosinophilic fasciitis following treatment with programmed cell death protein 1 or programmed cell death-ligand 1 blockade. All patients had extremity involvement with characteristic skin changes ranging from peripheral edema to induration, tightening, and joint limitation. The patients had varying degrees of peripheral eosinophilia. In two of our patients, the diagnosis was made by full-thickness skin biopsy showing lymphocytic infiltration of the subcutaneous fascia, with CD4+ T cells predominating in one case and CD8+ T cells in the other. In the other two cases, the diagnosis was made on the basis of characteristic imaging findings in the context of clinical features consistent with the diagnosis. All four patients were treated with glucocorticoids with varying degrees of success; immunotherapy had to be discontinued in all four. Patients with advanced melanoma who experienced this adverse effect had either a partial response or a complete response to therapy. CONCLUSION: Eosinophilic fasciitis can occur as a result of checkpoint inhibitor therapy. Although a tissue diagnosis is the gold standard, imaging studies may facilitate the diagnosis in the presence of consistent clinical features, but a degree of suspicion is key to recognizing the condition early. Therapy requires a collaborative approach by oncology, rheumatology, and dermatology; physical therapy is an important adjunct in treatment. For advanced melanoma, it may be a good prognostic indicator. IMPLICATIONS FOR PRACTICE: It is important for clinicians to recognize that eosinophilic fasciitis is a potential immune-related adverse event (irAE) as a consequence of immune checkpoint inhibitor therapy. The presentation is quite stereotypical; the diagnosis can be made by imaging in the absence of a full-thickness skin biopsy. Early intervention is important to limit morbidity. This irAE may be a good prognostic sign among patients with melanoma.