Claudio A. Mosse

T lymphocyte subset abnormalities in the blood and lung in pulmonary arterial hypertension.

RATIONALE Mounting data suggest that immune cell abnormalities participate in the pathogenesis of pulmonary arterial hypertension (PAH). OBJECTIVE To determine whether the T lymphocyte subset composition in the systemic circulation and peripheral lung is altered in PAH. METHODS Flow cytometric analyses were performed to determine the phenotypic profile of peripheral blood lymphocytes in idiopathic PAH (IPAH) patients (n=18) and healthy controls (n=17). Immunocytochemical analyses of lymphocytes and T cell subsets were used to examine lung tissue from PAH patients (n=11) and controls (n=11). MEASUREMENTS AND MAIN RESULTS IPAH patients have abnormal CD8+ T lymphocyte subsets, with a significant increase in CD45RA+ CCR7- peripheral cytotoxic effector-memory cells (p=0.02) and reduction of CD45RA+ CCR7+ naive CD8+ cells versus controls (p=0.001). Further, IPAH patients have a higher proportion of circulating regulatory T cells (T(reg)) and 4-fold increases in the number of CD3+ and CD8+ cells in the peripheral lung compared with controls (p<0.01). CONCLUSIONS Alterations in circulating T cell subsets, particularly CD8+ T lymphocytes and CD4+ T(reg), in patients with PAH suggest that a dysfunctional immune system contributes to disease pathogenesis. A preponderance of CD3+ and CD8+ T lymphocytes in the peripheral lung of PAH patients supports this concept.

Kikuchi-Fujimoto lymphadenitis: role of parvovirus B-19, Epstein-Barr virus, human herpesvirus 6, and human herpesvirus 8

Kikuchi-Fujimoto lymphadenitis is a self-limited disorder that typically presents in young females as painless cervical lymphadenopathy with fever, anemia, and leukopenia. The clinical manifestations and pathologic findings suggest a viral etiology, yet specific etiologic agents remain unknown. Although there are studies reporting positive associations between Kikuchi-Fujimoto lymphadenitis and parvovirus B19 and herpesviruses, other studies have failed to find an association with these viruses. To our knowledge, this current study is the largest study of Kikuchi-Fujimoto lymphadenitis in Western patients that used polymerase chain reaction testing for 4 different common viral pathogens often implicated as etiologic agents in Kikuchi-Fujimoto lymphadenitis. Archival material from 3 institutions was included, following confirmation of the diagnosis of Kikuchi-Fujimoto lymphadenitis by 2 independent pathologists. Polymerase chain reaction from the paraffin-embedded tissue sections for parvovirus B19, Epstein-Barr virus, human herpesvirus 6, and human herpesvirus 8 was performed. Eighteen cases of Kikuchi-Fujimoto lymphadenitis were analyzed, 12 of which (60%) were cervical lymph nodes. All the cases showed typical geographic necrosis with abundant apoptotic debris, although the degree of necrosis was variable. Polymerase chain reaction revealed a high prevalence of parvovirus B19 in the controls (44%); there were fewer positive cases seen in the Kikuchi-Fujimoto lymphadenitis cases (11%), but this did not reach statistical significance (P = .25).There were no significant differences between cases and controls in the prevalence of Epstein-Barr virus, human herpesvirus 6, and human herpesvirus 8 (P = .50 for all 3). Polymerase chain reaction failed to reveal a positive association between Kikuchi-Fujimoto lymphadenitis and 4 common suspected viral agents. These findings do not support a role for Epstein-Barr virus, human herpesvirus 6, human herpesvirus 8, or parvovirus B19 in the pathogenesis of Kikuchi-Fujimoto lymphadenitis.

NF-κB inducing kinase (NIK) modulates melanoma tumorigenesis by regulating expression of pro-survival factors through the β-catenin pathway

Nuclear factor-κB (NF-κB) inducing kinase (NIK) is a MAP3K that regulates the activation of NF-κB. NIK is often highly expressed in tumor cells, including melanoma, but the significance of this in melanoma progression has been unclear. Tissue microarray analysis of NIK expression reveals that dysplastic nevi (n=22), primary (n=15) and metastatic melanoma (n=13) lesions showed a statistically significant elevation in NIK expression when compared with benign nevi (n=30). Moreover, when short hairpin RNA techniques were used to knock-down NIK, the resultant NIK-depleted melanoma cell lines exhibited decreased proliferation, increased apoptosis, delayed cell cycle progression and reduced tumor growth in a mouse xenograft model. As expected, when NIK was depleted there was decreased activation of the non-canonical NF-κB pathway, whereas canonical NF-κB activation remained intact. NIK depletion also resulted in reduced expression of genes that contribute to tumor growth, including CXCR4, c-MYC and c-MET, and pro-survival factors such as BCL2 and survivin. These changes in gene expression are not fully explained by the attenuation of the non-canonical NF-κB pathway. Shown here for the first time is the demonstration that NIK modulates β-catenin-mediated transcription to promote expression of survivin. NIK-depleted melanoma cells exhibited downregulation of survivin as well as other β-catenin regulated genes including c-MYC, c-MET and CCND2. These data indicate that NIK mediates both β-catenin and NF-κB regulated transcription to modulate melanoma survival and growth. Thus, NIK may be a promising therapeutic target for melanoma.

Natural killer-cell neoplasms.

The natural killer (NK)-cell neoplasms are rare, representing less than 1% of non-Hodgkin lymphoma, except in Asia and Latin America, where they represent 3% to 6%. NK-cell neoplasms include immature acute leukemias; a blastic NK-cell lymphoma, which is obsolete because of its plasmacytoid dendritic-cell origin; and mature NK neoplasms, comprising extranodal NK/T-cell lymphoma (ENKL), nasal-type; aggressive NK-cell leukemia; and chronic NK-cell lymphoproliferative disorders, which are often reactive. Epstein-Barr virus is usually detected in tumor cells of ENKL and aggressive NK-cell leukemia. The latter two mature NK neoplasms are relatively chemoresistant because of the frequent expression of P-glycoprotein. Early radiation is advocated for localized nasal ENKL. Stem cell transplantation is recommended for advanced disease, owing to a poor prognosis. Novel agents, including chemotherapy, inhibitors of molecular pathways, and monoclonal antibodies, are under investigation.

Minimal Residual Disease in Myeloma: Are We There Yet?

Measurement of minimal residual disease is routine in diseases such as chronic myelogenous leukemia, precursor B cell acute lymphoblastic leukemia, and acute promyelocytic leukemia because it provides important prognostic information. However, the role of minimal residual disease testing has not been widely adopted in multiple myeloma (MM), with other parameters such as the International Staging System (ISS) and cytogenetic analysis primarily guiding therapy and determination of prognosis. Until recently, achieving a complete response (CR), as defined by the International Myeloma Working Group (IMWG) criteria, was rare in patients with MM. The use of novel agents with or without autologous peripheral blood stem cell transplantation (auto-PBSCT) has significantly increased CR rates, thus increasing overall survival (OS) rates. The majority of patients with MM have persistent levels of residual disease that are below the sensitivity of bone marrow (BM) morphology, protein electrophoresis with immunofixation, and light chain quantitation even after attaining CR and will eventually relapse. Measurement of minimal residual disease by more sensitive methods, and the use of these methods as a tool for predicting patient outcomes and guiding therapeutic decisions, has thus become more relevant. Methods available for monitoring minimal residual disease in MM include PCR and multiparameter flow cytometry (MFC), both of which have been shown to be valuable in other hematologic malignancies; however, neither has become a standard of care in MM. Here, we review current evidence for using minimal residual disease measurement for risk assessment in MM as well as incorporating pretreatment factors and posttreatment minimal residual disease monitoring as a prognostic tool for therapeutic decisions, and we outline challenges to developing uniform criteria for minimal residual disease monitoring.

Limited utility of fluorescence in situ hybridization for common abnormalities of myelodysplastic syndrome at first presentation and follow-up of myeloid neoplasms

Abstract Fluorescence in situ hybridization for abnormalities common to myelodysplastic syndrome (MDS FISH) is often used with traditional karyotype in the diagnosis and monitoring of myeloid neoplasms. However, its value in these roles has been questioned. To evaluate its utility, we compared MDS FISH results with karyotype in 544 bone marrow specimens obtained for diagnosis (180 cases) or follow-up (364 cases) of myeloid neoplasia. We found excellent concordance between FISH and karyotype, such that FISH is rarely abnormal (1.7% at diagnosis and 3.0% at follow-up) in cases with normal karyotype. Even in the rare discordant cases, the abnormal FISH has little or no clinical value. Thus, we propose that this test should be limited to cases with inadequate karyotype only. Such guidelines could result in significant cost savings with no impact on patient diagnosis.

Optimizing Personalized Bone Marrow Testing Using an Evidence-Based, Interdisciplinary Team Approach

OBJECTIVES To address the overuse of testing that complicates patient care, diminishes quality, and increases costs by implementing the diagnostic management team, a multidisciplinary system for the development and deployment of diagnostic testing guidelines for hematologic malignancies. METHODS The team created evidence-based standard ordering protocols (SOPs) for cytogenetic and molecular testing that were applied by pathologists to bone marrow biopsy specimens on adult patients. Testing on 780 biopsy specimens performed during the six months before SOP implementation was compared with 1,806 biopsy specimens performed during the subsequent 12 months. RESULTS After implementation, there were significant decreases in tests discordant with SOPs, omitted tests, and the estimated cost of testing to payers. The fraction of positive tests increased. Clinicians reported acceptance of the new procedures and perceived time savings. CONCLUSIONS This process is a model for optimizing complex and personalized diagnostic testing.

Clinicopathologic Correlation of Epidemiologic and Histopathologic Features of Pediatric Bacterial Lymphadenitis

CONTEXT Infection is a common cause of lymphadenopathy in children and has numerous microbial etiologies. Lymph node biopsy is considered a keystone in arriving at a definite diagnosis. An accurate differential diagnosis from a lymph node biopsy can expedite diagnosis and minimize ancillary testing. OBJECTIVE To assess and compare the histopathologic and epidemiologic features of common and uncommon pediatric bacterial lymphadenitis. DESIGN We searched our database for surgical specimens that had a positive identification of bacteria during an 8-year period. The chart was reviewed to assess the pathogen identified and epidemiologic data. The archival tissue sections were reviewed and the histopathologic findings described for each pathogen. RESULTS The review of 368 pediatric lymph node biopsies identified 33 cases with a bacterial infection. These comprised 21 cases of Mycobacterium avium complex (60%), 1 of Mycobacterium fortuitum (3%), 7 of Bartonella henselae (20%), 2 of Yersinia enterocolitica (7%), 1 of Francisella tularensis (3%) and 1 of Streptococcus pyogenes (3%). CONCLUSIONS Each of these infectious lymphadenitides had distinct epidemiologic and histopathologic features that are discussed in this report.

Methylation of promoters of microRNAs and their host genes in myelodysplastic syndromes

Abstract Myelodysplastic syndromes (MDS) are a group of hematopoietic malignancies characterized by ineffective hematopoiesis. Recently, we identified MDS-associated microRNAs (miRNAs) that are down-regulated in MDS. This study examines possible explanations for that observed down-regulation of miRNA expression in MDS. Since genomic losses are insufficient to explain the down-regulation of all our MDS-associated miRNAs, we explored other avenues. We demonstrate that these miRNAs are predominantly intragenic, and that, in many cases, they and their host genes are expressed in a similar pattern during myeloid maturation, suggesting their co-regulation. This co-regulation is further supported by the down-regulation of several of the host genes in MDS and increased methylation of the shared promoters of several miRNAs and their respective host genes. These studies identify a role of hypermethylation of miRNA promoters in the down-regulation of MDS-associated miRNAs, unifying research on miRNAs in MDS and epigenetic regulation in MDS into a common pathway.

Quantitative Assessment of Myeloid Nuclear Differentiation Antigen Distinguishes Myelodysplastic Syndrome From Normal Bone Marrow

By using flow cytometry, we analyzed myeloid nuclear differentiation antigen (MNDA) expression in myeloid precursors in bone marrow from patients with myelodysplastic syndrome (MDS) and control samples from patients undergoing orthopedic procedures. The median percentage of MNDA-dim myeloid precursors in MDS cases was 67.4% (range, 0.7%-97.5%; interquartile range, 44.9%-82.7%) of myeloid cells, with bimodal MNDA expression in most MDS samples. Control samples demonstrated a median MNDA-dim percentage in myeloid precursors of 1.2% (range, 0.2%-13.7%; interquartile range, 0.6%-2.7%), with no bimodal pattern in most samples. The area under the receiver operating characteristic curve for MNDA-dim percentage in myeloid precursors was 0.96 (P = 9 × 10(-7)). Correlation of MNDA-dim levels with World Health Organization 2008 morphologic diagnoses was not significant (P = .21), but correlation with patient International Prognostic Scoring System scores suggested a trend (P = .07). Flow cytometric assessment of MNDA in myeloid precursors in bone marrow may be useful for the diagnosis of MDS.