Plasmablastic lymphoma: an HIV-associated entity with primary oral manifestations

Plasmablastic lymphoma is a relatively new entity that is considered to be a diffuse large B-cell lymphoma with an unique immunophenotype and a predilection for the oral cavity. We present a 50 year-old HIV-positive, bisexual, white male with a CD4 count 300/mm(3) and a viral HIV-RNA polymerase chain reaction (PCR) load of 237 copies/ml, who developed a painful, purple-red mass in the edentulous area of the maxillary right first molar. Erythematous gingival enlargements of the interdental papillae were seen in three of the dental quadrants. In addition, the patient was being managed with antiretroviral therapy and liposomal doxorubicin for recurrent cutaneous Kaposi's sarcoma (KS). Although oral KS was suspected, the gingival lesions were biopsied because they were refractory to chemotherapy and a lymphoma could not be excluded. Histopathologic examination revealed a lymphoid malignant neoplasm, consistent with a plasmablastic lymphoma. Immunoreactivity with vs38c, CD79a, kappa light chain, and IgG was readily identified in tumor cells; while only focal cells expressed CD20 and LCA (CD45RB). CD56, CD3, lambda light chain, and EMA were non-reactive. EBV was detected in the tumor by Southern hybridization, PCR amplification, in situ hybridization for EBER-1 DNA, and immunohistochemistry for latent membrane protein-1. The same tumor was negative for HHV-8 by PCR. Recognition of plasmablastic lymphoma is important, because it represents an HIV-associated malignancy that predominantly involves the oral cavity, may mimic KS and has a poor prognosis.

Persistent productive Epstein-Barr virus replication in normal epithelial cells in vivo

Productive Epstein-Barr virus (EBV) replication characterizes hairy leukoplakia, an oral epithelial lesion typically occurring in individuals infected with human immunodeficiency virus (HIV). Serial tongue biopsy specimens were obtained from HIV-infected subjects before, during, and after valacyclovir treatment. EBV replication was detected by Southern hybridization to linear terminal EBV genome fragments, reverse-transcriptase polymerase chain reaction amplification of EBV replicative gene transcripts, immunohistochemical detection of EBV replicative protein, and in situ hybridization to EBV DNA. EBV replication was detected in both hairy leukoplakia and normal tongue tissues. Valacyclovir treatment completely abrogated EBV replication in vivo, resulting in resolution of hairy leukoplakia when it was present. EBV replication returned in normal tongue epithelial cells after valacyclovir treatment. These data suggest that normal oral epithelium supports persistent EBV infection in individuals infected with HIV and that productive EBV replication is necessary but not sufficient for the pathogenesis of oral hairy leukoplakia.

Oral hairy leukoplakia: an Epstein-Barr virus-associated disease of patients with HIV

Oral hairy leukoplakia is a common, benign, opportunistic EBV infection of the oral cavity of patients with HIV. It is important to differentiate hairy leukoplakia from other, more serious, oral lesions that may have a similar clinical appearance. In some cases, this is best accomplished by biopsy and histologic examination of the tissue. Several treatment options are available for symptomatic hairy leukoplakia lesions, but none prevent the recurrence of the lesion after therapy. Research studies into the pathogenesis and treatment of oral hairy leukoplakia and other HIV-associated and EBV-associated oral lesions are currently being conducted at the Bering Dental Clinic in Houston.

The molecular epidemiology and evolution of Epstein-Barr virus: sequence variation and genetic recombination in the latent membrane protein-1 gene

The phylogeny and evolution of Epstein-Barr virus (EBV) genetic variation are poorly understood. EBV latent membrane protein-1 (LMP-1) gene sequences are especially heterogeneous and may be useful as a tool for EBV genotype identification. Therefore, LMP-1 sequences obtained directly from EBV-infected human tissues were examined by PCR amplification and cloning. EBV genotypes were defined as "strains" from among 22 identified LMP-1 sequence patterns. Three molecular mechanisms were identified by which genetic diversity arises in the LMP-1 gene: point mutation, sequence deletion or duplication, and homologous recombination. The rate of LMP-1 gene evolution was found to be accelerated by coinfection with multiple EBV strains. The results of this study refine our understanding of LMP-1 sequence variation and enable accurate discrimination between independent EBV infection events and the consequence of intrahost EBV evolution. Thus, this LMP-1 sequence-based approach to EBV molecular epidemiology will facilitate the study of intrahost EBV infection, coinfection, and persistence.

Epstein-Barr virus coinfection and recombination in non-human immunodeficiency virus-associated oral hairy leukoplakia

Human immunodeficiency virus-associated oral hairy leukoplakia (HLP) is characterized by coinfection with multiple types and strains of Epstein-Barr virus (EBV) and recombination within the EBV genome. HIV-seronegative immunosuppressed and immunocompetent patients with HLP were examined to determine the pathogenic contribution of EBV coinfection and recombination to the development of HLP. Multiple coinfecting EBV strains were detected in both HLP specimens and peripheral blood lymphocytes (PBL) of HIV-seronegative persons with HLP. One specific EBV strain was detected in HLP specimens from 3 of 4 patients. Also, viral recombination during productive replication within HLP generated variants of the latent membrane protein-1 (LMP-1) and nuclear antigen-2 (EBNA-2) genes. Some variants were also detected within PBL. Thus, EBV coinfection and recombination are consistent findings in persons with HLP regardless of immune status. Virally mediated determinants may be important features of EBV pathogenesis.

The Epstein-Barr virus EBNA-2 gene in oral hairy leukoplakia: strain variation, genetic recombination, and transcriptional expression

Oral hairy leukoplakia (HLP) lesions frequently contain defective Epstein-Barr virus (EBV) genomes with deletions in the EBNA-2 gene that abundantly replicate and persist within the lesion. To characterize these viral strains and recombinant variants, the EBNA-2 gene in EBV DNA from several different HLP biopsy specimens was analyzed. Amplification of EBNA-2 coding sequences by PCR demonstrated the presence in HLP of intact EBNA-2 genes as well as a variety of internally deleted variants of both EBNA-2A and EBNA-2B. Some of the deletion variants evolved within the HLP lesion from intact EBNA-2 genes, while other variants appeared to be transmissible strains that directly infected the lesion. Intrastrain recombination within the HLP lesion also generated variation within the EBNA-2 polyproline region. Cloning and sequencing of HLP cDNA demonstrated transcription from the internally deleted EBNA-2 open reading frame, indicating that these variant genes are expressed in HLP. Comparative analysis of the HLP EBNA-2 sequences confirmed previous findings of EBV coinfection with multiple types and strains. Sequence variation of these wild-type genes demonstrated that EBNA-2A sequences distinguish at least two separate strains and a variety of substrains of EBV type 1. Two of the HLP EBNA-2A sequences contained amino acid changes in a cytotoxic T-cell epitope within an otherwise highly conserved region of the gene. These data indicate that EBV coinfection, strain variation, and recombination within the EBNA-2 gene are common features of HLP and suggest that the expression of internally deleted EBNA-2 variants could contribute to EBV pathogenesis in permissive infection.

Epstein-Barr virus intrastrain recombination in oral hairy leukoplakia

In laboratory lymphoblastoid cell lines and in natural human infections, Epstein-Barr virus (EBV) strains have been identified by DNA restriction fragment length polymorphisms of the BamHI H fragment. Multiple, heterogeneous BamHI H fragments have been detected in oral hairy leukoplakia (HLP), raising the question of EBV coinfection with multiple strains. To investigate whether the heterogeneous BamHI H fragments represent different EBV strains or recombinant variants of the same strain, EBV DNA from HLP lesions was analyzed to characterize the viral strains and determine the source of possible recombinant variants. Clones of heterogeneous BamHI H fragments from a single HLP lesion were determined to have strain identity on the basis of sequence identity of the EBNA-2 genes. Intrastrain homologous recombination within the IR2 internal repeat region and nonhomologous recombination of other sequences accounted for the heterogeneity of the BamHI H fragments. PCR amplification from additional HLP specimens detected similar recombinant variants. A possible example of site-specific recombination joining the BamHI Y portion of the EBNA-2 gene to sequences within the BamHI S fragment was also detected in multiple HLP specimens. These data indicate that intrastrain recombination during productive replication confounds the use of restriction fragment length polymorphism analysis of the BamHI Y and H fragments to identify EBV strains in HLP. In patients with permissive epithelial EBV infections, EBV strains could be more accurately distinguished by sequence identity or divergence within known regions of genetic strain variation.

Sequence variation in the Epstein-Barr virus latent membrane protein 1

The sequence of the latent membrane protein 1 (LMP-1) gene was analysed in Epstein-Barr virus (EBV) isolates from specific regions representing both type 1 and type 2 EBV. A predominant strain marked by an XhoI restriction enzyme polymorphism (REP) within the LMP-1 gene has been identified in type 1 EBV in nasopharyngeal carcinoma (NPC) from Southern China. This polymorphism was also present in type 2 EBV in NPC from Alaska. In this study, the sequence of the LMP-1 gene was determined in these samples representing type 1 and type 2 EBV and was compared with the prototype lymphoid strains. Consistent nucleotide variation in the amino terminus of LMP-1 was identified in strains marked by the XhoI REP. These changes were present in both EBV type 1 and type 2 strains. Three types of sequence variation were detected in the carboxy terminus of LMP-1. The LMP-1 sequences differed in the number of an 11 amino acid repeat element. In the prototype EBV type 1 (B95-8) sequence and in the type 1 Raji and type 2 HR-1 strains, the third repeat element contained an insertion of 5 amino acids that were also the first five unique amino acids after the last partial repeat element. The third variation was a deletion of amino acids 343 to 352 of the B95-8 LMP-1. This deletion was detected in the type 1 Chinese EBV strains, but was not detected in the type 2 Alaskan strains although the Chinese and Alaskan strains have nearly identical amino acid changes at the amino terminus. Numerous other amino acid changes were detected in the carboxy terminus which did not cosegregate with either EBV type, amino acid changes in the amino terminus, or specific geographic regions. These data indicate that EBV strains can be distinguished by sequence differences within LMP-1 and that unlike the divergence between type 1 and type 2 EBV in Epstein-Barr nuclear antigen sequences, different EBV types are nearly identical in LMP-1 sequence.

Epstein-Barr virus (EBV) gene expression in EBV-positive peripheral T-cell lymphomas

Epstein-Barr virus (EBV) DNA has been detected in peripheral T-cell lymphomas. In this study, analysis of the EBV termini indicated that the infection was clonal and nonpermissive. Analysis of viral expression detected the processed, spliced mRNAs representing EBNA1, LMP1, LMP2, and BamHI A transcripts in all EBV-positive peripheral T-cell lymphomas. The LMP1 protein was detected by immunofluorescence in a single specimen. In contrast, neither the EBNA2 protein nor the spliced EBNA2 mRNA were detected. These data indicate that EBV-infected T-cell lymphomas are clonal expansions of a single EBV-infected cell with a pattern of gene expression which is distinct from that detected in Burkitt's lymphomas or posttransplant lymphomas but similar to viral expression in nasopharyngeal carcinomas.

Coinfection with multiple strains of the Epstein-Barr virus in human immunodeficiency virus-associated hairy leukoplakia

Epstein-Barr virus DNA was analyzed from specimens of hairy leukoplakia, an oral lesion that occurs in patients infected with the human immunodeficiency virus. The simultaneous presence of both type 1 and type 2 Epstein-Barr virus was demonstrated by Southern blot analysis and polymerase chain reaction assay. Restriction fragment length polymorphisms in the BamHI WYH region and in clones of the EcoRI C region suggested the presence of multiple strains of type 1 and type 2 viruses. The demonstration of multiple variably sized BamHI H fragments on Southern blot analysis and cloning of the EBNA-2 gene coding region also suggested the presence of multiple viral strains or variants coinfecting hairy leukoplakia. Recombination of the viral genome in and around the EBNA-2 gene apparently generated viral variants that replicated efficiently, one of which appeared to increase in abundance in a lesion over time. These data indicate that hairy leukoplakia involves coinfection with multiple strains of replicating Epstein-Barr virus and the endogenous generation of viral variants, some of which have mutations of the EBNA-2 gene.

Pyomyositis in patients with diabetes mellitus

Pyomyositis is a pyogenic infection of skeletal muscle that is endemic in the tropics and is being recognized with increasing frequency in temperate climates. We report two cases of nonendemic pyomyositis in patients with diabetes mellitus. A review of the literature suggests that diabetes mellitus may be an important risk factor for the development of pyomyositis. Possible mechanisms of this association are discussed.

Disseminated infection with Trichosporon beigelii

Two cases of systemic infection with Trichosporon beigelii are reported. Both patients had acute leukemia and were receiving cytotoxic and antibiotic drug therapy, which included amphotericin B, at the time of sepsis. Although clinical isolates of the organisms were found to be sensitive to amphotericin B in vitro, both patients died from severe, widespread fungal infection. The pathologic findings in these two cases suggest that the host response to trichosporon infection is a granulomatous inflammation. Trichosporon is a virulent opportunistic pathogen that may originate from the gastrointestinal tract damaged by cytotoxic therapy in the patient with aplasia. Despite aggressive antifungal therapy, survival is most closely related to recovery of the host's hematopoietic system.

Immunologic effects of interferon-alpha in man: treatment with human recombinant interferon-alpha suppresses in vitro immunoglobulin production in patients with chronic type B hepatitis

The effect of human recombinant interferon-alpha on lymphocyte proliferation and differentiation was studied in 18 patients with chronic type B hepatitis who were participating in a randomized controlled trial of interferon-alpha therapy. Peripheral blood mononuclear cells (PBMC) were obtained by lymphopheresis before and during a 4 mo course of interferon. Pokeweed mitogen-induced immunoglobulin synthesis by PBMC obtained from patients before therapy was similar to that of PBMC from normal individuals. However, after 2 wk treatment with human recombinant interferon-alpha mitogen-induced immunoglobulin production was decreased by an average of 50%. Staining for cytoplasmic immunoglobulin revealed decreases that paralleled secreted immunoglobulin, indicating that interferon-alpha treatment inhibited immunoglobulin synthesis. Mixing autologous T and B cell enriched populations from before and during interferon treatment revealed that the decrease in immunoglobulin synthesis involved a defect in the B cell-enriched population. In contrast to immunoglobulin synthesis, pokeweed mitogen-induced lymphocyte proliferation was not significantly affected by in vivo administration of interferon-alpha. Thus a major effect of in vivo interferon-alpha on immunoregulation in patients with chronic type B hepatitis appears to be an inhibition of the late stages of B cell differentiation into immunoglobulin producing and secreting plasma cells.

Immunologic effects of interferon-alpha in man: treatment with human recombinant interferon-alpha suppresses in vitro immunoglobulin production in patients with chronic type B hepatitis

The effect of human recombinant interferon-alpha on lymphocyte proliferation and differentiation was studied in 18 patients with chronic type B hepatitis who were participating in a randomized controlled trial of interferon-alpha therapy. Peripheral blood mononuclear cells (PBMC) were obtained by lymphopheresis before and during a 4 mo course of interferon. Pokeweed mitogen-induced immunoglobulin synthesis by PBMC obtained from patients before therapy was similar to that of PBMC from normal individuals. However, after 2 wk treatment with human recombinant interferon-alpha mitogen-induced immunoglobulin production was decreased by an average of 50%. Staining for cytoplasmic immunoglobulin revealed decreases that paralleled secreted immunoglobulin, indicating that interferon-alpha treatment inhibited immunoglobulin synthesis. Mixing autologous T and B cell enriched populations from before and during interferon treatment revealed that the decrease in immunoglobulin synthesis involved a defect in the B cell-enriched population. In contrast to immunoglobulin synthesis, pokeweed mitogen-induced lymphocyte proliferation was not significantly affected by in vivo administration of interferon-alpha. Thus a major effect of in vivo interferon-alpha on immunoregulation in patients with chronic type B hepatitis appears to be an inhibition of the late stages of B cell differentiation into immunoglobulin producing and secreting plasma cells.

Immune effects of alpha-interferon in chronic liver disease

The effect of prolonged alpha-interferon therapy on immune function was studied in patients with chronic type B hepatitis. These patients with chronic type B hepatitis have been shown to have a defect in their in vitro response to human recombinant alpha-interferon. This defect consists of a failure to augment pokeweed mitogen-stimulated immunoglobulin production at low concentrations of interferon and an increased susceptibility to the suppressive effects of interferon. After 2 weeks therapy with interferon, immunoglobulin production was further suppressed. However, after 4 months of therapy with interferon, pokeweed mitogen-stimulated immunoglobulin production partially returned towards the pretreatment values. Antibody to hepatitis B core antigen was less affected by interferon therapy. This altered response to interferon was not specific as it was seen in some patients with other forms of liver disease. The suppression of B cell differentiation appears to be separate from its antiviral and antiproliferative effects.