Prevalence and cellular reservoir of latent human herpesvirus 6 in tonsillar lymphoid tissue.

There are few studies that examine prevalence, quantity, and cellular proclivity of latent human herpesvirus 6 (HHV-6) in healthy populations. We examined 69 tonsils with paired blood specimens from children without evidence of acute infection. By polymerase chain reaction (PCR), HHV-6 was detected at low levels in 100% of tonsils and 39% of blood samples (n = 27), suggesting that prevalence of latent HHV-6 infection is high in children and may be underestimated by PCR analysis of blood. Although HHV-6A and HHV-6B were detected, HHV-6B predominated, being found in 97% of samples (n = 67). Tonsil sections from 7 cases were examined by in situ hybridization using 2 HHV-6 probes and immunohistochemical analysis. Using both in situ hybridization and immunohistochemical analysis, all tissues revealed marked HHV-6-specific staining in the squamous epithelium of the tonsillar crypts and rare positive lymphocytes. We conclude that HHV-6 is present universally in tonsils of children, and tonsillar epithelium may be an important viral reservoir in latent infection.

Immunophenotypic analysis of peripheral T-cell neoplasms. A multiparameter flow cytometric approach.

We retrospectively reviewed multiparameter flow cytometric analyses in 50 peripheral T-cell neoplasms (PTCNs). Results were interpreted within the context of a large cohort of nonneoplastic T-cell populations. All PTCN diagnoses were confirmed with morphologic and/or molecular analysis. Aberrant populations were defined as discrete immunophenotypic clusters exhibiting loss of or increased or diminished expression of T-cell antigens relative to internal immunophenotypically normal T-cell populations. An antigenic pattern was considered abnormal if it exceeded ranges for T-cell subsets in specific anatomic sites or was not normally encountered. Forty-six of 50 and 41 of 50 demonstrated 1 or more and 2 or more aberrations, respectively. The most common abnormally expressed antigen was CD3, followed by CD7, CD5, and CD2. Except for CD7, abnormally dim or bright antigen expression was more common than deletion. Only 3 cases were abnormal solely based on expansion of an otherwise immunophenotypically normal population; the remainder had patterns of antigen expression not seen in nonneoplastic populations. These data indicate that most PTCNs are aberrant by multiparameter flow analysis. However, results must be interpreted within the context of thorough knowledge of the immunophenotypic spectrum of nonneoplastic T cells.

Large cell lymphoma transformation of chronic lymphocytic leukemia/small lymphocytic lymphoma. A flow cytometric analysis of seven cases.

We studied 7 cases of large cell transformation of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) immunophenotyped by multiparameter flow cytometry. The 6 women and 1 man ranged in age from 45 to 91 years. All had previous or concurrent evidence of CLL/SLL. Morphologic features and sites of involvement of the diffuse large B-cell lymphoma (DLBCL) were heterogeneous; 2 cases had paraimmunoblastic morphologic features. Six DLBCLs had an immunophenotype consistent with CLL: CD19+, CD5+, CD23+, and FMC7 negative (3 cases) or very dim (2 cases); 1 case was not studied for FMC7. CD20 was dim in 3 of these, moderate to bright in 2, and variable in 1. Surface immunoglobulin was dim in 2 cases and moderate or bright in 4. Five of 6 expressed CD38. Comparison with the immunophenotypes of the previous or coexistent CLL/SLL (4 of 6 cases) revealed minor modulations in antigen expression but no major alterations. The seventh DLBCL lacked CD5 expression, but otherwise had immunophenotypic features similar to CLL. These findings indicate that DLBCL arising in CLL/SLL tends to retain a CLL immunophenotype, in contrast with de novo CD5+ large cell lymphomas that uncommonly express such a phenotype.

Activation of HIV in human skin by ultraviolet B radiation and its inhibition by NFkappaB blocking agents.

To determine whether ultraviolet B (UVB) irradiation leads to activation of HIV in human skin, we conducted prospective and controlled studies in two academic medical centers in Texas from July 1995 to April 1999. HIV-positive patients with UV-treatable skin diseases were enrolled at each center, 18 subjects at one and 16 at the other. In one center, specimens from lesional and nonlesional skin biopsies were taken before and after sham- or UVB-irradiation administered in vivo or in vitro. In the other center, UVB phototherapy was administered three times weekly and specimens from skin biopsies were taken before and after 2 weeks (six treatments). Cutaneous HIV load was assessed using reverse transcriptase-polymerase chain reaction and reverse transcriptase-polymerase chain reaction in situ hybridization. UVB irradiation led to a 6-10-fold increase in the number of HIV in skin. To ascertain a role for nuclear factor kappa B (NFkappaB) in UVB-inducible HIV activation, two types of blockers, NFkappaB oligonucleotide decoy and sodium salicylate, were tested; each inhibited UVB-inducible HIV activation in skin partially. We conclude that UVB irradiation leads to increased numbers of HIV in human skin via processes that include release of cytoplasmic NFkappaB.

Cytomegalovirus and human herpesvirus 6, but not human papillomavirus, are present in neonatal giant cell hepatitis and extrahepatic biliary atresia.

The purpose of our study was to confirm reports of an association of human papillomavirus (HPV) with neonatal giant cell hepatitis (GCH) and biliary atresia (BA), and to expand these studies to include cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV6), and parvovirus B19 (PVB19). Frozen hepatic tissue was available for polymerase chain reaction (PCR) analysis in 19 cases of GCH or BA and 8 controls. Nested PCR to detect HPV types 6, 16, 18, and 33 was followed by 32P hybridization with generic probes. PCR followed by hybridization with a digoxigenin-labeled probe was used for all other viruses. HPV, EBV, and PVB19 were not detected in cases or controls. Two cases of GCH and 1 case of BA were PCR positive for CMV; controls were negative. HHV6 was detected in 6 cases: 2 GCH, 2 BA, and 2 controls. We conclude that HPV is not associated with GCH or BA. Detection of CMV in BA and GCH confirms other reports of this association. HHV6 requires further study to determine the significance of a positive PCR test in the livers of infants.

Precursor B-lymphoblastic transformation of grade I follicle center lymphoma.

Part of the natural history of follicle center lymphoma (FCL) is transformation to a more aggressive neoplasm, almost always a diffuse large B-cell lymphoma. We describe a rare example of a precursor B-lymphoblastic transformation of grade I FCL occurring in a 45-year-old woman 12 years after initial presentation and 3 years after successful treatment for a diffuse large cell transformation. The lymphoblastic lymphoma shared the same immunoglobulin heavy chain gene rearrangement as the FCL as assessed by polymerase chain reaction amplification and direct sequencing, as well as identical kappa light chain gene rearrangements by Southern blot analysis. The immunoglobulin heavy chain variable gene sequences of both tumors showed numerous identical base substitutions compared with germline sequences and 3 additional mutations in the lymphoblastic lymphoma not present in the low-grade FCL. These results indicate origin of the lymphoblastic process from the mature follicle center B-cell clone, rather than divergent origin of the 2 tumors from a common immature B-cell precursor.

Predictive value of quantitative PCR-based viral burden analysis for eight human herpesviruses in pediatric solid organ transplant patients.

Human herpesviruses can cause significant morbidity and mortality in pediatric solid organ transplant recipients. It was hypothesized that viral burden quantification by polymerase chain reaction using an internal calibration standard could aid in distinguishing between viral disease and latency. Here we report the results of a 2-year prospective study of 27 pediatric solid organ (liver, kidney, or heart) transplant recipients in which multiple samples were analyzed for levels of all eight human herpesviruses by internal calibration standard-polymerase chain reaction. Herpes simplex viruses 1 and 2, varicella-zoster virus, and Kaposi's sarcoma-associated herpesvirus were not detected in any of these samples. Human herpesvirus types 6 and 7 were detected in half of the patients, but were present at low levels, similar to those found in reference populations. Epstein-Barr virus (EBV) and cytomegalovirus (CMV) were detected in 89% and 56% of the patients, respectively. Viral burden analysis suggested distinct patient populations for CMV, with a natural cutoff of 10,000 viral targets/ml blood strongly associated with disease. In some cases, a dramatic increase in CMV levels preceded clinical evidence of disease by several weeks. EBV viral burden was relatively high in the only patient presenting with an EBV syndrome. However, two other patients without evidence of EBV disease had single samples with high EBV burden. Rapid reduction in both EBV and CMV burden occurred with antiviral treatment. These data suggest that viral burden analysis using internal calibration standard-polymerase chain reaction for CMV, and possibly other herpesviruses, is an effective method for monitoring pediatric transplant patients for significant herpesvirus infection and response to therapy.

Quantitation of 8 human herpesviruses in peripheral blood of human immunodeficiency virus-infected patients and healthy blood donors by polymerase chain reaction.

Human herpesviruses are associated with morbidity and mortality in persons with compromised immune systems, including patients infected with human immunodeficiency virus (HIV). To investigate the basis for this association, the levels of all 8 human herpesviruses (herpes simplex virus, types 1 and 2, varicella-zoster virus, cytomegalovirus, Epstein-Barr virus, and human herpesvirus 6, human herpesvirus 7, and human herpesvirus 8) were measured with the quantitative polymerase chain reaction (PCR). Viral DNA was measured in the whole blood of 20 HIV-infected patients and compared with levels in 20 healthy blood donors. There was no significant difference in the frequency of virus detection of the 8 human herpesviruses between HIV-infected patients and healthy adults. These results indicate that HIV infection is not associated with a general increase in the circulating levels of human herpesviruses, and suggest that quantitative PCR analysis is superior to qualitative PCR analysis for detection of clinically relevant disease in HIV-infected patients.

Human herpesvirus-6 and sudden death in infancy: report of a case and review of the literature.

Investigation of sudden death in infancy is a vital function of the medical examiner's office. Surveillance of these cases may lead to recognition of new diseases or new manifestations of previously described diseases. Human herpesvirus-6 (HHV-6) is a relatively newly described virus that has been recognized as a cause of acute febrile illness in early childhood. While most cases are apparently self-limited, seven fatal cases have been reported. We present a case of a seven-month-old Latin American male with recent otitis media and vomiting who was found dead in bed. Autopsy revealed interstitial pneumonitis with an atypical polymorphous lymphocytic infiltrate in the liver, kidney, heart, spleen, lymph nodes, and bone marrow, associated with erythrophagocytosis. Polymerase chain reaction (PCR) analysis of formalin-fixed paraffin-embedded tissue was positive for HHV-6 and negative for Epstein-Barr virus (EBV) and cytomegalovirus (CMV). HHV-6 was also detected in the atypical lymphoid infiltrate by in-situ hybridization.

Epstein-Barr virus polymerase chain reaction and serology in pediatric post-transplant lymphoproliferative disorder: three-year experience.

To assess whether the semiquantitative peripheral blood Epstein-Barr virus (EBV) polymerase chain reaction (PCR) test correlates with post-transplant lymphoproliferative disorder (LPD), we compiled the results of the test done over a 3-year period ending July 1997. Six hundred seventy-six tests were done on 185 patients. Four hundred-thirty tests (63%) were negative, 167 (25%) were weak positive, 67 (10%) were moderate positive, and 12 (2%) were strong positive. Twelve of the patients developed a lymphoproliferative disorder (LPD) during this time. The EBV PCR tests proximate to the diagnosis of LPD in the 12 patients with EBV-positive LPD were 6 strong positive, 5 moderate positive, 1 weak positive. No patient with LPD had a negative result at diagnosis. Stated another way, 6/12 (50%) of strong-positive PCR tests, 5/67 (7%) moderate-positive tests, and 1/167 (.6%) of weak-positive tests correlated with LPD. Serologic evaluation for EBV done on 7 patients at the time of LPD showed low serologic responses in 5 of the 7 patients. The EBV PCR temporally associated with the serology indicated moderate to large viral burdens. In each patient evaluated serially, the EBV PCR test rose before the diagnosis of LPD and fell with treatment for the disorder. In conclusion, the EBV PCR test may be used as an adjunct to the diagnosis of patients with LPD and may be used to monitor response to therapy for the disorder.

Polymerase chain reaction amplification of archival material for Epstein-Barr virus, cytomegalovirus, human herpesvirus 6, and parvovirus B19 in children with bone marrow hemophagocytosis.

Bone marrow hemophagocytosis may occur as an incidental finding, or it may be a manifestation of a systemic and potentially lethal disorder. When systemic, the proliferation is termed hemophagocytic lymphohistiocytosis (HLH), a clinicopathologic entity characterized by a widespread proliferation of benign hemophagocytic histiocytes, fever, pancytopenia, deranged liver function, and frequently coagulopathy and hepatosplenomegaly. A variety of infectious agents, including Epstein-Barr virus (EBV), cytomegalovirus (CMV), human herpesvirus 6 (HHV6), and parvovirus B19 (PVB19), have been associated with HLH, but the relative frequency of each using one technique has not been evaluated. In addition, infectious causes of incidental bone marrow hemophagocytosis, not occurring in the setting of HLH, have not been evaluated. Review of bone marrow reports from bone marrow examinations done between December 1986 and June 1997 showed that 20 children aged 2 months to 15 years had bone marrow examinations that indicated hemophagocytosis. Archival materials from 19 patients were successfully retrieved, and DNA was extracted from archived unstained coverslips with subsequent polymerase chain reaction for EBV, CMV, HHV6, and PVB19 genomic DNA. DNA extracted from 16 bone marrow specimens of age-matched children was used as negative controls. Eleven of the 19 patients fulfilled the clinical and pathological criteria for HLH; the remaining eight patients had isolated hemophagocytosis without a systemic presentation. Viral DNA was detected in 8 of 11 patients with HLH but in none of eight patients with isolated hemophagocytosis. EBV was present in five of the bone marrows, followed in frequency by HHV6, CMV, and PVB19. Infection with more than one agent was present in three patients. Only one control patient was positive for HHV6 DNA; the remaining control patients were negative for all viruses. Viral infection, detected by PCR analysis of bone marrow, is a common finding in patients with HLH but not in patients with isolated bone marrow hemophagocytosis. This technique may provide another marker to aid in the diagnosis of HLH and suggests a different cause of hemophagocytosis occurring in patients with and without HLH.

Quantitative polymerase chain reaction for human herpesvirus diagnosis and measurement of Epstein-Barr virus burden in posttransplant lymphoproliferative disorder.

Human herpesviruses can cause acute diseases such as chicken pox or mononucleosis, but also may reactivate during immunosuppression and result in severe or life-threatening illnesses such as shingles or lymphoproliferative disorders. We report the development and validation of a quantitative PCR method to measure viral burden for all eight human herpesviruses (HSV1, HSV2, VZV, EBV, CMV, HHV6, HHV7, and KSHV) in patients' samples. The method uses an internal standard that is coamplified with the viral target, allowing quantification of viral genomes in absolute terms (e.g., viral targets/mL of blood) and ruling out false-negative results. We demonstrate that transplant patients with lymphoproliferative disorder carry an EBV viral burden 3 logs higher than nontransplant patients. EBV titers in transplant patients without a lymphoproliferative disorder are between these values. This quantitative PCR method may aid in differentiating clinically significant vs latent viral burden in immunosuppressed patients.

Epstein-Barr virus PCR correlated with viral histology and serology in pediatric liver transplant patients.

Epstein-Barr virus (EBV)-associated illnesses in posttransplant patients are difficult to diagnose. Attempts to aid in the diagnosis of such illnesses using the polymerase chain reaction (PCR) analysis for EBV have met with variable success due to the potential exquisite sensitivity of the assay. We have designed a relatively insensitive EBV PCR assay and compared the results with objective evidence of EBV activity including serologic response and in situ hybridization for the EBV genome. Eighty-five specimens from 65 patients were analyzed by the EBV PCR using DNA from whole blood. EBV serologic evaluation was done on 53 of the samples and in situ hybridization for EBV (EBER-1 mRNA) on 46 paired liver biopsies. Of 85 samples, 25 (29%) were positive for EBV using the PCR assay. Intensity of amplification was graded 0.5-1+ (weak) to 3+ (strong). Using these criteria, 19 EBV PCR-positive samples were graded 0.5-1+, 5 were graded 2+, and 1 was graded 3+. Of the moderate to strongly positive samples (2+ or 3+), five of six had two or more EBER-1-positive cells in the liver biopsies. Of the remaining 40 liver biopsies with either negative or weak positive PCR results, 3 had only single cells positive for EBER-1; the remainder were negative. In addition, PCR-positive results correlated with increasing EBV anti-early antigen antibody (P = .005) and viral capsid antigen IgG immunoglobulin G VCA (P = .05) EBV-positive results using the PCR assay correlated with objective evidence for increased EBV burden in children after liver transplantation. These preliminary data suggest that this PCR test may be useful to help guide immunosuppressive therapy in the posttransplant patient. Further evaluation using larger numbers of patients will be necessary to confirm this.

Rapid, nonradioactive screening for mutations in exons 10, 11, and 16 of the RET protooncogene associated with inherited medullary thyroid carcinoma.

Germline mutations in exons 10, 11, and 16 of the RET protooncogene are associated with the heritable cancer syndromes multiple endocrine neoplasia (MEN) type 2A, familial medullary thyroid carcinoma (FMTC), and MEN type 2B. Nonradioactive mutation analysis with nondenaturing Phastgels and the Phast System was performed on DNA amplified by the polymerase chain reaction from exons 10, 11, and 16 of the RET protooncogene from patients with MEN 2A, MEN 2B, or FMTC. The analysis requires approximately 45-90 min for electrophoresis and 35 min for staining. This assay detected 20 of 21 different mutations that represented approximately 90% of all known mutations associated with these lesions. A rare silent polymorphism within exon 10 was also detected. This form of mutation analysis provides simple, rapid, and highly sensitive nonradioactive detection of mutations known to be associated with MEN 2A, FMTC, and MEN 2B.

Assignment of the human peroxisomal branched-chain acyl-CoA oxidase gene to chromosome 3p21.1-p14.2 by rodent/human somatic cell hybridization.

PCR and rodent/human somatic cell hybrids were used to localize the human peroxisomal branched-chain acyl-CoA oxidase gene. Oligonucleotide primers were chosen to specifically amplify human hBCox DNA. The amplified sequence contained two restriction enzyme sites which were used to verify the authenticity of the amplified DNA. Initially, the gene was localized to human chromosome 3 by screening genomic DNA from a hybrid mapping panel. Additional hybrids retaining well-characterized fragments of human chromosome 3 were screened to further localize the gene to 3p21.1.p14.2.

Primary effusion lymphoma: a distinct clinicopathologic entity associated with the Kaposi's sarcoma-associated herpes virus.

We recently discovered the Kaposi's sarcoma-associated herpes virus (KSHV/HHV-8) in an uncommon and unusual subset of AIDS-related lymphomas that grow mainly in the body cavities as lymphomatous effusions without an identifiable contiguous tumor mass. The consistent presence of KSHV and certain other distinctive features of these body cavity-based lymphomas suggest that they represent a distinct entity. We tested this hypothesis by investigating 19 malignant lymphomatous effusions occurring in the absence of a contiguous tumor mass for their clinical, morphologic, immunophenotypic, viral, and molecular characteristics, KSHV was present in 15 of 19 lymphomas. All four KSHV-negative lymphomatous effusions exhibited Burkitt or Burkitt-like morphology and c-myc gene rearrangements and, therefore, appeared to be Burkitt-type lymphomas occurring in the body cavities. In contrast, all 15 KSHV-positive lymphomatous effusions exhibited a distinctive morphology bridging large-cell immunoblastic lymphoma and anaplastic large-cell lymphoma, and all 12 cases studied lacked c-myc gene rearrangements. In addition, these lymphomas occurred in men (15/15), frequently but not exclusively in association with HIV infection (13/15), in which homosexuality was a risk factor (13/13), presented initially as a lymphomatous effusion (14/15), remained localized to the body cavity of origin (13/15), expressed CD45 (15/15) and one or more activation-associated antigens (9/10) in the frequent absence of B-cell-associated antigens (11/15), exhibited clonal immunoglobulin gene rearrangements (13/13), contained Epstein-Barr virus (14/15), and lacked bcl-2, bcl-6, ras and p53 gene alterations (13/15). These findings strongly suggest that the KSHV-positive malignant lymphomatous effusions represent a distinct clinicopathologic and biologic entity and should be distinguished from other malignant lymphomas occurring in the body cavities. Therefore, we recommend that these malignant lymphomas be designated primary effusion lymphomas (PEL), rather than body cavity-based lymphomas, since this term describes them more accurately and avoids their confusion with other malignant lymphomas that occur in the body cavities. We further recommend that these PEL be considered for inclusion as a new entity in the Revised European-American Lymphoma Classification.

Whole blood levels of dodecanoic acid, a routinely detectable forensic marker for a genetic disease often misdiagnosed as sudden infant death syndrome (SIDS): MCAD deficiency.

We investigated whether or not elevated whole blood dodecanoic acid concentration was due to a beta-oxidation defect in fatty acid metabolism previously reported. We prospectively analyzed blood from 55 consecutive sudden infant death syndrome (SIDS) cases for fatty acid concentrations by gas chromatograph. Three of 55 cases had elevated dodecanoic acid concentrations (> or = 18.4 mg/L). The three SIDS cases with elevated blood dodecanoic acid were confirmed to have medium chain acyl-CoA dehydrogenase (MCAD) deficiency by outside laboratories, indicating that elevated dodecanoic acid is highly specific and sensitive for predicting MCAD deficiency in SIDS victims. Dodecanoic acid was easily detected in routine toxicology for acid and neutral drugs done at autopsy. MCAD deficiency is an autosomal recessive genetic disease, carrying a 25% recurrence risk. Families should be notified that siblings, both presently living and yet to be born, should be screened for this deficiency because MCAD deficiency can be treated, and sudden, unexplained infant deaths of living and subsequent offspring can be prevented.

Primary body cavity-based AIDS-related lymphomas.

Five patients with advanced AIDS developed a unique type of high grade primary body cavity-based non-Hodgkin's lymphoma (NHL). The lymphomas were exclusively in serous effusions with no detectable mass disease in the body cavities and no lymphadenopathy or organomegaly. All of the lymphomas exhibited virtually identical morphology, which could not be precisely classified, but appeared to bridge features of large cell immunoblastic and anaplastic large cell lymphomas. Immunophenotypically the lymphoma cells lacked expression of any B- or T-lymphocyte antigens, but expressed CD45 and the activation antigens CD30, CD38, CD71, and HLA-DR. Clonally rearranged immunoglobulin heavy chain and kappa light chain genes were identified by Southern blot analysis. Molecular studies also revealed Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) genomes and germline configuration of the c-myc protooncogene. In two cases studied cytogenetically, the lymphoma cells manifested complex chromosome abnormalities. These lymphomas are clinically and biologically unique and found predominantly in patients with advanced AIDS, in many cases with pre-existing Kaposi's sarcoma.

Epstein-Barr virus-associated leiomyosarcomas in liver transplantation recipients. Origin from either donor or recipient tissue.

BACKGROUND: Leiomyosarcoma, a mesenchymal malignancy with smooth muscle differentiation, is extremely rare in children. Immunosuppression, due to either antirejection medication in organ transplantation recipients or human immunodeficiency virus infection (HIV), appears to constitute a predisposition. METHODS: Two cases of leiomyosarcoma in pediatric liver transplantation recipients were investigated and compared clinically with respect to site of origin and course of the disease and pathologically by routine histology and electron microscopy, by forensic DNA methodology for origin from donor or recipient tissue, and by EBER-1 in situ hybridization for evidence of latent Epstein-Barr virus (EBV) infection. RESULTS: A 9-year-old male developed a high grade, poorly differentiated leiomyosarcoma in his allografted liver 2 years after transplantation, and despite antineoplastic chemotherapy, he died of metastatic disease. The genotype of his tumor indicated an origin from allografted tissue. A 12-year-old female had a low grade retroperitoneal leiomyosarcoma involving the superior mesenteric vein. After resection, she remained disease free without chemotherapy. The genotype of her tumor indicated an origin from native tissue. In both tumors, latent EBV infection was documented. CONCLUSIONS: Neoplastic smooth muscle proliferation in immunosuppressed liver transplantation recipients is analogous to the more common posttransplantation lymphoproliferative disorder in involving transformation of either engrafted donor tissue or recipient tissue elsewhere in the body, in displaying a wide spectrum of histologic differentiation, grade and clinical behavior, and in exhibiting evidence of latent EBV infection.