Leveraging gene expression subgroups to classify DLBCL patients and select for clinical benefit from a novel agent.

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease, commonly described by cell-of-origin (COO) molecular subtypes. We sought to identify novel patient subgroups through an unsupervised analysis of a large public dataset of gene expression profiles from newly diagnosed de novo DLBCL patients, yielding 2 biologically distinct subgroups characterized by differences in the tumor microenvironment. Pathway analysis and immune deconvolution algorithms identified higher B-cell content and a strong proliferative signal in subgroup A and enriched T-cell, macrophage, and immune/inflammatory signals in subgroup B, reflecting similar biology to published DLBCL stratification research. A gene expression classifier, featuring 26 gene expression scores, was derived from the public dataset to discriminate subgroup A (classifier-negative, immune-low) and subgroup B (classifier-positive, immune-high) patients. Subsequent application to an independent series of diagnostic biopsies replicated the subgroups, with immune cell composition confirmed via immunohistochemistry. Avadomide, a CRL4CRBN E3 ubiquitin ligase modulator, demonstrated clinical activity in relapsed/refractory DLBCL patients, independent of COO subtypes. Given the immunomodulatory activity of avadomide and the need for a patient-selection strategy, we applied the gene expression classifier to pretreatment biopsies from relapsed/refractory DLBCL patients receiving avadomide (NCT01421524). Classifier-positive patients exhibited an enrichment in response rate and progression-free survival of 44% and 6.2 months vs 19% and 1.6 months for classifier-negative patients (hazard ratio, 0.49; 95% confidence interval, 0.280-0.86; P = .0096). The classifier was not prognostic for rituximab, cyclophosphamide, doxorubicin, vincristine, prednisone or salvage immunochemotherapy. The classifier described here discriminates DLBCL tumors based on tumor and nontumor composition and has potential utility to enrich for clinical response to immunomodulatory agents, including avadomide.

Novel poxvirus infection in 2 patients from the United States.

BACKGROUND: Some human poxvirus infections can be acquired through zoonotic transmission. We report a previously unknown poxvirus infection in 2 patients, 1 of whom was immunocompromised; both patients had known equine contact. METHODS: The patients were interviewed and clinical information was abstracted from the patients' medical files. Biopsies of the skin lesions were collected from both patients for histopathology, immunohistochemistry, and transmission electron microscopy analysis. Oral and skin swabs were collected from animals with frequent contact with the patients, and environmental sampling including rodent trapping was performed on the farm where the immunosuppressed patient was employed. "Pan-pox and high Guanine-cytosine" polymerase chain reaction assays were performed on patient, animal, and environmental isolates. Amplicon sequences of the viral DNA were used for agent identification and phylogenetic analysis. RESULTS: Specimens from both human cases revealed a novel poxvirus. The agent shares 88% similarity to viruses in the Parapoxvirus genus and 78% to those in the Molluscipoxvirus genus but is sufficiently divergent to resist classification as either. All animal and environmental specimens were negative for poxvirus and both patients had complete resolution of lesions. CONCLUSIONS: This report serves as a reminder that poxviruses should be considered in cutaneous human infections, especially in individuals with known barnyard exposures. The clinical course of the patients was similar to that of parapoxvirus infections, and the source of this virus is currently unknown but is presumed to be zoonotic. This report also demonstrates the importance of a comprehensive approach to diagnosis of human infections caused by previously unknown pathogens.

Acute muscular sarcocystosis: an international investigation among ill travelers returning from Tioman Island, Malaysia, 2011-2012.

BACKGROUND: Through 2 international traveler-focused surveillance networks (GeoSentinel and TropNet), we identified and investigated a large outbreak of acute muscular sarcocystosis (AMS), a rarely reported zoonosis caused by a protozoan parasite of the genus Sarcocystis, associated with travel to Tioman Island, Malaysia, during 2011-2012. METHODS: Clinicians reporting patients with suspected AMS to GeoSentinel submitted demographic, clinical, itinerary, and exposure data. We defined a probable case as travel to Tioman Island after 1 March 2011, eosinophilia (>5%), clinical or laboratory-supported myositis, and negative trichinellosis serology. Case confirmation required histologic observation of sarcocysts or isolation of Sarcocystis species DNA from muscle biopsy. RESULTS: Sixty-eight patients met the case definition (62 probable and 6 confirmed). All but 2 resided in Europe; all were tourists and traveled mostly during the summer months. The most frequent symptoms reported were myalgia (100%), fatigue (91%), fever (82%), headache (59%), and arthralgia (29%); onset clustered during 2 distinct periods: "early" during the second and "late" during the sixth week after departure from the island. Blood eosinophilia and elevated serum creatinine phosphokinase (CPK) levels were observed beginning during the fifth week after departure. Sarcocystis nesbitti DNA was recovered from 1 muscle biopsy. CONCLUSIONS: Clinicians evaluating travelers returning ill from Malaysia with myalgia, with or without fever, should consider AMS, noting the apparent biphasic aspect of the disease, the later onset of elevated CPK and eosinophilia, and the possibility for relapses. The exact source of infection among travelers to Tioman Island remains unclear but needs to be determined to prevent future illnesses.

Exserohilum infections associated with contaminated steroid injections: a clinicopathologic review of 40 cases.

September 2012 marked the beginning of the largest reported outbreak of infections associated with epidural and intra-articular injections. Contamination of methylprednisolone acetate with the black mold, Exserohilum rostratum, was the primary cause of the outbreak, with >13,000 persons exposed to the potentially contaminated drug, 741 confirmed drug-related infections, and 55 deaths. Fatal meningitis and localized epidural, paraspinal, and peripheral joint infections occurred. Tissues from 40 laboratory-confirmed cases representing these various clinical entities were evaluated by histopathological analysis, special stains, and IHC to characterize the pathological features and investigate the pathogenesis of infection, and to evaluate methods for detection of Exserohilum in formalin-fixed, paraffin-embedded (FFPE) tissues. Fatal cases had necrosuppurative to granulomatous meningitis and vasculitis, with thrombi and abundant angioinvasive fungi, with extensive involvement of the basilar arterial circulation of the brain. IHC was a highly sensitive method for detection of fungus in FFPE tissues, demonstrating both hyphal forms and granular fungal antigens, and PCR identified Exserohilum in FFPE and fresh tissues. Our findings suggest a pathogenesis for meningitis involving fungal penetration into the cerebrospinal fluid at the injection site, with transport through cerebrospinal fluid to the basal cisterns and subsequent invasion of the basilar arteries. Further studies are needed to characterize Exserohilum and investigate the potential effects of underlying host factors and steroid administration on the pathogenesis of infection.

Myocardial injury and bacterial pneumonia contribute to the pathogenesis of fatal influenza B virus infection.

BACKGROUND: Influenza B virus infection causes rates of hospitalization and influenza-associated pneumonia similar to seasonal influenza A virus infection and accounts for a substantial percentage of all influenza-related hospitalizations and deaths among those aged <18 years; however, the pathogenesis of fatal influenza B virus infection is poorly described. METHODS: Tissue samples obtained at autopsy from 45 case patients with fatal influenza B virus infection were evaluated by light microscopy and immunohistochemical assays for influenza B virus, various bacterial pathogens, and complement components C4d and C9, to identify the cellular tropism of influenza B virus, characterize concomitant bacterial pneumonia, and describe the spectrum of cardiopulmonary injury. RESULTS: Viral antigens were localized to ciliated respiratory epithelium and cells of submucosal glands and ducts. Concomitant bacterial pneumonia, caused predominantly by Staphylococcus aureus, was identified in 38% of case patients and occurred with significantly greater frequency in those aged >18 years. Pathologic evidence of myocardial injury was identified in 69% of case patients for whom cardiac tissue samples were available for examination, predominantly in case patients aged <18 years. CONCLUSIONS: Our findings suggest that bacterial pneumonia and cardiac injury contribute to fatal outcomes after infection with influenza B virus and that the frequency of these manifestations may be age related.

Solid organ transplant-associated lymphocytic choriomeningitis, United States, 2011.

Three clusters of organ transplant-associated lymphocytic choriomeningitis virus (LCMV) transmissions have been identified in the United States; 9 of 10 recipients died. In February 2011, we identified a fourth cluster of organ transplant-associated LCMV infections. Diabetic ketoacidosis developed in the organ donor in December 2010; she died with generalized brain edema after a short hospitalization. Both kidneys, liver, and lung were transplanted to 4 recipients; in all 4, severe posttransplant illness developed; 2 recipients died. Through multiple diagnostic methods, we identified LCMV infection in all persons, including in at least 1 sample from the donor and 4 recipients by reverse transcription PCR, and sequences of a 396-bp fragment of the large segment of the virus from all 5 persons were identical. In this cluster, all recipients developed severe illness, but 2 survived. LCMV infection should be considered as a possible cause of severe posttransplant illness.

Rift Valley fever virus vaccine lacking the NSs and NSm genes is safe, nonteratogenic, and confers protection from viremia, pyrexia, and abortion following challenge in adult and pregnant sheep.

Rift Valley fever virus (RVFV) is a mosquito-borne human and veterinary pathogen causing large outbreaks of severe disease throughout Africa and the Arabian Peninsula. Safe and effective vaccines are critically needed, especially those that can be used in a targeted one-health approach to prevent both livestock and human disease. We report here on the safety, immunogenicity, and efficacy of the ΔNSs-ΔNSm recombinant RVFV (rRVFV) vaccine (which lacks the NSs and NSm virulence factors) in a total of 41 sheep, including 29 timed-pregnant ewes. This vaccine was proven safe and immunogenic for adult animals at doses ranging from 1.0 × 10(3) to 1.0 × 10(5) PFU administered subcutaneously (s.c.). Pregnant animals were vaccinated with 1.0 × 10(4) PFU s.c. at day 42 of gestation, when fetal sensitivity to RVFV vaccine-induced teratogenesis is highest. No febrile reactions, clinical illness, or pregnancy loss was observed following vaccination. Vaccination resulted in a rapid increase in anti-RVFV IgM (day 4) and IgG (day 7) titers. No seroconversion occurred in cohoused control animals. A subset of 20 ewes progressed to full-term delivery after vaccination. All lambs were born without musculoskeletal, neurological, or histological birth defects. Vaccine efficacy was assessed in 9 pregnant animals challenged at day 122 of gestation with virulent RVFV (1.0 × 10(6) PFU intravenously). Following challenge, 100% (9/9) of the animals were protected, progressed to full term, and delivered healthy lambs. As expected, all 3 sham-vaccinated controls experienced viremia, fetal death, and abortion postchallenge. These results demonstrate that the ΔNSs-ΔNSm rRVFV vaccine is safe and nonteratogenic and confers high-level protection in sheep.

Blastomycosis in man after kinkajou bite.

We report transmission of Blastomyces dermatitidis fungal infection from a pet kinkajou to a man. When treating a patient with a recalcitrant infection and a history of an animal bite, early and complete animal necropsy and consideration of nonbacterial etiologies are needed.

Fatal bluetongue virus infection in an alpaca (Vicugna pacos) in California.

In October 2008, a 15-year-old female alpaca (Vicugna pacos) housed at a breeding farm in northern California died after a brief illness characterized by sudden onset of weakness, recumbency, and respiratory distress. Postmortem examination revealed severe hydrothorax and hydropericardium, marked pulmonary edema, and acute superficial myocardial hemorrhage affecting the left ventricle. Bluetongue virus (BTV) was detected in the spleen by quantitative real-time reverse transcription polymerase chain reaction and confirmed by sequence analysis. No antibodies against BTV were detected in the serum using a competitive enzyme-linked immunosorbent assay, confirming acute, fulminant BTV infection.

Intraventricular granulomatous mass associated with Mycobacterium haemophilum: A rare central nervous system manifestation in a patient with human immunodeficiency virus infection.

We report a rare case of Mycobacterium haemophilum presenting as an intraventricular granulomatous mass with loculated hydrocephalus and seizures in a patient with human immunodeficiency virus. M. haemophilum, a slow-growing mycobacteria, causes localized and disseminated disease among immunocompromised hosts. Central nervous system infection with M. haemophilum is extremely rare. Preoperative laboratory testing of our patient for tuberculosis, toxoplasmosis, sarcoidosis and histoplasmosis were negative. Surgical resection of the mass revealed a caseating granuloma that stained positive for acid-fast bacillus suggesting possible tuberculoma. Despite negative testing for tuberculosis, a polymerase chain reaction analysis was ultimately performed from the resected mass which revealed M. haemophilum. To our knowledge, this is the first case of M. haemophilum presenting as an intraventricular mass. We review the clinical manifestations of this pathogen and discuss the medical and surgical management.

Cerebral Angiostrongylus cantonensis infection in a captive African pygmy falcon (Polihierax semitorquatus) in southern California.

A 10-month-old, female African pygmy falcon (Polihierax semitorquatus) hatched and housed at the San Diego Zoo developed neurologic signs and died from a cerebral infection with the rat lungworm Angiostrongylus cantonensis. There was an associated mild nonsuppurative meningoencephalitis. This infection was diagnosed on histology and confirmed by detection of species-specific A. cantonensis DNA in formalin-fixed and frozen brain tissue by a polymerase chain reaction assay. To the authors' knowledge, this infection has not previously been reported in a bird in the United States and has not been known to be naturally acquired in any species in this region of the world. The source of the infection was not definitively determined but was possibly feeder geckos (Hemidactylus frenatus) imported from Southeast Asia where the parasite is endemic.

Single-dose replication-defective VSV-based Nipah virus vaccines provide protection from lethal challenge in Syrian hamsters.

Nipah virus (NiV) continues to cause outbreaks of fatal human encephalitis due to spillover from its bat reservoir. We determined that a single dose of replication-defective vesicular stomatitis virus (VSV)-based vaccine vectors expressing either the NiV fusion (F) or attachment (G) glycoproteins protected hamsters from over 1000 times LD50 NiV challenge. This highly effective single-dose protection coupled with an enhanced safety profile makes these candidates ideal for potential use in livestock and humans.

Fatal transplant-associated west nile virus encephalitis and public health investigation-california, 2010.

BACKGROUND: In December 2010, a case of West Nile virus (WNV) encephalitis occurring in a kidney recipient shortly after organ transplantation was identified. METHODS: A public health investigation was initiated to determine the likely route of transmission, detect potential WNV infections among recipients from the same organ donor, and remove any potentially infected blood products or tissues. Available serum, cerebrospinal fluid, and urine samples from the organ donor and recipients were tested for WNV infection by nucleic acid testing and serology. RESULTS: Two additional recipients from the same organ donor were identified, their clinical and exposure histories were reviewed, and samples were obtained. WNV RNA was retrospectively detected in the organ donor's serum. After transplantation, the left kidney recipient had serologic and molecular evidence of WNV infection and the right kidney recipient had prolonged but clinically inapparent WNV viremia. The liver recipient showed no clinical signs of infection but had flavivirus IgG antibodies; however, insufficient samples were available to determine the timing of infection. No remaining infectious products or tissues were identified. CONCLUSIONS: Clinicians should suspect WNV as a cause of encephalitis in organ transplant recipients and report cases to public health departments for prompt investigation of the source of infection. Increased use of molecular testing and retaining pretransplantation sera may improve the ability to detect and diagnose transplant-associated WNV infection in organ transplant recipients.

Alternatives to retroorbital blood collection in hispid cotton rats (Sigmodon hispidus).

Cotton rats (Sigmodon hispidus) are a valuable animal model for many human viral diseases, including polio virus, measles virus, respiratory syncytial virus, and herpes simplex virus. Although cotton rats have been used in research since 1939, few publications address handling and sampling techniques for this species, and the retroorbital sinus remains the recommended blood sampling site. Here we assessed blood sampling methods that are currently used in other species and a novel subzygomatic sampling site for their use in S. hispidus. The subzygomatic approach accesses a venous sinus that possibly is unique to this species and that lies just below the zygomatic arch of the maxilla and deep to the masseter muscle. We report that both the novel subzygomatic approach and the sublingual vein method can be used effectively in cotton rats.

Coxiella burnetii infection of marine mammals in the Pacific Northwest, 1997-2010.

Q fever is a zoonotic disease caused by the bacterium Coxiella burnetii. Humans are commonly exposed via inhalation of aerosolized bacteria derived from the waste products of domesticated sheep and goats, and particularly from products generated during parturition. However, many other species can be infected with C. burnetii, and the host range and full zoonotic potential of C. burnetii is unknown. Two cases of C. burnetii infection in marine mammal placenta have been reported, but it is not known if this infection is common in marine mammals. To address this issue, placenta samples were collected from Pacific harbor seals (Phoca vitulina richardsi), harbor porpoises (Phocoena phocoena), and Steller sea lions (Eumetopias jubatus). Coxiella burnetii was detected by polymerase chain reaction (PCR) in the placentas of Pacific harbor seals (17/27), harbor porpoises (2/6), and Steller sea lions (1/2) collected in the Pacific Northwest. A serosurvey of 215 Pacific harbor seals sampled in inland and outer coastal areas of the Pacific Northwest showed that 34.0% (73/215) had antibodies against either Phase 1 or Phase 2 C. burnetii. These results suggest that C. burnetii infection is common among marine mammals in this region.

The pox in the North American backyard: Volepox virus pathogenesis in California mice (Peromyscus californicus).

Volepox virus (VPXV) was first isolated in 1985 from a hind foot scab of an otherwise healthy California vole (Microtus californicus). Subsequent surveys in San Mateo County, CA, revealed serological evidence suggesting that VPXV is endemic to this area, and a second viral isolate from a Pinyon mouse (Peromyscus truei) was collected in 1988. Since then, few studies have been conducted regarding the ecology, pathology, and pathogenicity of VPXV, and its prevalence and role as a potential zoonotic agent remain unknown. To increase our understanding of VPXV disease progression, we challenged 24 California mice (Peromyscus californicus) intranasally with 1.6 × 10(3) PFU of purified VPXV. By day five post infection (pi) we observed decreased activity level, conjunctivitis, ruffled hair, skin lesions, facial edema, and crusty noses. A mortality rate of 54% was noted by day eight pi. In addition, internal organ necrosis and hemorrhages were observed during necropsy of deceased or euthanized animals. Viral loads in tissues (brain, gonad, kidney, liver, lung, spleen, submandibular lymph node, and adrenal gland), bodily secretions (saliva, and tears), and excretions (urine, and/or feces) were evaluated and compared using real time-PCR and tissue culture. Viral loads measured as high as 2 × 10(9) PFU/mL in some organs. Our results suggest that VPXV can cause extreme morbidity and mortality within rodent populations sympatric with the known VPXV reservoirs.

Ruptured mycotic aortic aneurysm in a sooty mangabey (Cercocebus atys).

Mycotic aortic aneurysm is a local, irreversible dilatation of the aorta associated with destruction of the vessel wall by infection and is a grave clinical condition associated with high morbidity and mortality in humans. Rupture of aortic aneurysms can be spontaneous, idiopathic, or due to severe trauma, and the condition has been associated with bacterial and, rarely, fungal infections in humans and animals. Here, we describe a case of ruptured spontaneous aortic aneurysm associated with zygomycetic infection in a 21-y-old female sooty mangabey. The animal did not present with any significant clinical signs before being found dead. At necropsy, she was in good body condition, and the thoracic cavity had a large amount of clotted blood filling the left pleural space and surrounding the lung lobes. Near the aortic arch, the descending thoracic aorta was focally perforated (diameter, approximately 0.15 cm), and clotted blood adhered to the tunica adventitia. The aortic intima had multiple, firm, pale-yellow nodules (diameter, 0.25 to 0.5 cm). Histopathologically, these nodules consisted of severe multifocal pyogranulomatous inflammation intermixed with necrosis, fibrin, and broad, infrequently septate, thin-walled fungal hyphae. Immunohistochemistry revealed fungal hyphae characteristic of Mucormycetes (formerly Zygomycetes), and PCR analysis identified the organism as Basidiobolus spp. Dissemination of the fungus beyond the aorta was not noted. Spontaneous aortic aneurysms have been described in nonhuman primates, but this is the first reported case of a ruptured spontaneous aortic aneurysm associated with entomophthoromycetic infection in a sooty mangabey.

Bluetongue virus infection activates bovine monocyte-derived macrophages and pulmonary artery endothelial cells.

Bluetongue virus (BTV) is the cause of bluetongue (BT), an emerging, arthropod-transmitted disease of ungulates. The cellular tropism of BTV in ruminants includes macrophages, dendritic cells and endothelial cells (ECs), and fulminant infection is characterized by lesions consistent with those of so-called viral hemorrhagic fevers. Specifically, BT is characterized by vascular injury with hemorrhage, tissue infarction and widespread edema. To further investigate the pathogenesis of vascular injury in BT, we evaluated the responses of cultured bovine pulmonary artery EC (bPAEC) and monocyte-derived macrophages (bMDM) to BTV infection by measuring transcript levels of genes encoding molecules important in mediating EC activation and/or endothelial barrier dysregulation. The data confirm that BTV infection of bPAEC resulted in increased transcription of genes encoding chemokine ligand 2 (CCL2) and E-selectin, and BTV infection of bMDM resulted in increased transcription of genes encoding TNF-alpha, IL-1beta, IL-8, and inducible nitric oxide synthase (iNOS). The data from these in vitro studies provide further evidence that cytokines and other vasoactive substances produced in macrophages potentially contribute to vascular injury in BTV-infected ruminants, along with direct effects of the virus itself on ECs.