Health-related quality of life and radiographic vertebral fracture

BACKGROUND

Vertebral fractures are associated with back pain and disability; however, relatively little is known about the impact of radiographic vertebral fractures on quality of life in population samples. The aim of this study was to determine the impact of a recent radiographic vertebral fracture on health-related quality of life (HRQoL).

METHODS

Men and women aged 50 years and over were recruited from population registers in 12 European centers. Subjects completed an interviewer-administered questionnaire and had lateral spine radiographs performed. Subjects in these centers were followed prospectively and had repeat spinal radiographs performed a mean of 3.8 years later. Prevalent deformities were defined using established morphometric criteria, and incident vertebral fractures by both morphometric criteria and qualitative assessment. For each incident fracture case, three controls matched for age, gender, and center were selected: one with a prevalent deformity (at baseline) and two without prevalent deformities. All subjects were interviewed or completed a postal questionnaire instrument which included Short Form 12 (SF-12), the EQ-5D (former EuroQol), and the quality of life questionnaire of the International Osteoporosis Foundation (QUALEFFO). The median time from the second spinal radiograph until the quality of life survey was 1.9 years. Comparison between cases and their matched controls was undertaken using the signed rank test.

RESULTS

73 subjects with incident vertebral fracture (cases), mean age 64.8 years (of whom 23 had a baseline deformity), and 196 controls, mean age 63.9 years (of whom 60 had a baseline deformity), were studied. There were strong correlations between the domain scores for each of the three instruments. There was no statistically significant difference in any of the domain scores between cases and those controls with a prevalent deformity. However, compared with the controls without a prevalent deformity the cases had significantly impaired quality of life as determined using the total QUALEFFO score (38.2 vs 33.7), the physical component score of the SF-12 (39.9 vs 43.7) and the health status score of the EQ-5D (62.3 vs 69.9). When the analysis was repeated after stratification of the cases by baseline deformity status (i.e., cases with and without a prevalent deformity at baseline), cases with a prevalent deformity had impaired quality of life compared with their matched controls, both with and without a prevalent deformity. In contrast there was no significant difference in quality of life among the cases without a prevalent deformity and either control group.

CONCLUSIONS

In this population-based study a recent vertebral fracture was associated with impairment in quality of life, though this was mainly among those who had sustained a previous vertebral deformity.

Prevalence of obesity in an elderly Hungarian population

BACKGROUND

There are few cross-sectional population-based studies on obesity in Hungary. Aim of this study was to characterize the prevalence, associated diseases and metabolic laboratory parameters for obesity in men and women in Budapest, Hungary.

METHODS

A random sample of 641 persons (307 males and 334 females) aged 50 years and over were recruited from a population register in Budapest. Subjects were interviewed, had height and weight measured in standard fashion. Those who were obese (BMI > 30.0 kg/m2) were matched individually with non-obese subjects. Altogether 101 pairs (48 women and 53 men pairs) were taking part and these subjects had blood taken for amount of serum glucose, lipids and uric acid.

RESULTS

The mean age of men and women was 65.0 (SD = 9.1) years and 64.6 (SD = 8.9) years, respectively. The prevalence of obesity was 18.1% in men and 15.4% in women (p < 0.05). In both sexes the mean body mass index was higher at age of 50-64 years than at older ages [in men 27.2 (SD = 3.7) kg/m2 vs. 26.7 (SD = 3.3) kg/ m2, p = 0.286 and in women 26.7 (SD = 4.2) kg/m2 vs. 25.4 (SD = 4.0) kg/m2, p = 0.005]. Body mass index was higher in men than in women at all ages. In the case-control study the mean age of obese and non-obese individuals were 63.1 (SD = 7.8) years and 63.2 (SD = 7.9) years, respectively. Obesity was significantly associated with a history of diabetes mellitus (18 vs. 7%, p < 0.05) and hypertension (48 vs. 28%, p < 0.05). Compared to the non-obese, those who were obese had a higher level of serum uric acid (311 +/- 102 vs. 280 +/- 96 micromol/l, p < 0.05) and triglyceride (2.67 +/- 1.95 vs. 1.86 +/- 0.95 mmol/l, p < 0.05).

CONCLUSION

The high prevalence of obesity both in elderly men and women and its strong association with chronic diseases causes economical and social burden for Hungary. Strategies and programs for weight maintenance as well as weight reduction must become a higher public health priority.

Interleukin-6 and granulocyte-macrophage colony-stimulating factor in apical periodontitis: correlation with clinical and histologic findings of the involved teeth

Apical periodontitis is characterized by the presence of immunocompetent cells producing a wide variety of inflammatory mediators. Releasing cytokines with long-range action, such as interleukin-6 (IL-6) and granulocyte-macrophage colony-stimulating factor (GM-CSF), apical periodontitis may induce changes in remote organs of the host. This study quantified the levels of IL-6 and GM-CSF in symptomatic and asymptomatic human periradicular lesions. Lesions were also characterized by size and histologic findings. Tissue samples were homogenized and supernatants were assayed using an enzyme-linked immunosorbent assay (ELISA). Correlations between cytokine levels and characteristic features (as single variables) of the lesions were analysed. There was a trend for higher levels of IL-6 and GM-CSF in symptomatic than in asymptomatic lesions, but the difference was not significant. Levels also tended to be higher in large than in small lesions, in polymorphonuclear (PMN) cell-rich than in PMN cell-poor samples, and in epithelialized than in non-epithelialized lesions. Significantly higher levels of IL-6 (778.1 +/- 220.5 pg/microg) and GM-CSF (363.3 +/- 98.4 pg/microg) were found in samples coincidentally possessing symptomatic and epithelialized features than in asymptomatic, small, PMN cell-poor, non-epithelialized lesions (IL-6: 45.2 +/- 13.1 pg/microg and GM-CSF: 135.1 +/- 26.4 pg/microg). These results suggest that symptomatic lesions containing epithelial cells represent an immunologically active stage of apical periodontitis, whereas asymptomatic, small, PMN cell-poor, non-epithelialized lesions represent healing apical lesions.

Kynurenate production by cultured human astrocytes

In the rodent brain, astrocytes are known to be the primary source of kynurenate (KYNA), an endogenous antagonist of both the glycine(B) and the alpha7 nicotinic acetylcholine receptor. In the present study, primary human astrocytes were used to examine the characteristics and regulation of de novo KYNA synthesis in vitro. To this end, cells were exposed to KYNA's bioprecursor L-kynurenine, and newly formed KYNA was recovered from the extracellular milieu. The production of KYNA was stereospecific and rose with increasing L-kynurenine concentrations, reaching a plateau in the high microM range. In an analogous experiment, astrocytes also readily produced and liberated the potent, specific glycine(B) receptor antagonist 7-chlorokynurenate from L-4-chlorokynurenine. KYNA synthesis was dose-dependently reduced by L-leucine or L-phenylalanine, two amino acids that compete with L-kynurenine for cellular uptake, and by aminooxyacetate, a non-specific aminotransferase inhibitor. In contrast, KYNA formation was stimulated by 5 mM pyruvate or oxaloacetate, which act as co-substrates of the transamination reaction. Aglycemic or depolarizing (50 mM KCl or 100 microM veratridine) conditions had no effect on KYNA synthesis. Subsequent studies using tissue homogenate showed that both known cerebral kynurenine aminotransferases (KAT I and KAT II) are present in astrocytes, but that KAT II appears to be singularly responsible for KYNA formation under physiological conditions. Taken together with previous results, these data suggest that very similar mechanisms control KYNA synthesis in the rodent and in the human brain. These regulatory events are likely to influence the neuromodulatory effects of astrocyte-derived KYNA in the normal and diseased human brain.

Risk factors for diffuse idiopathic skeletal hyperostosis: a case-control study

OBJECTIVE

Diffuse idiopathic skeletal hyperostosis (DISH) is a skeletal disease characterized by ligamentous ossification of the anterolateral side of the spine. The aim of this study was to characterize risk factors associated with DISH.

METHODS

Subjects were recruited for participation in a screening survey of vertebral osteoporosis. The cases were 69 men and 62 women with DISH and the controls were 69 men and 62 women with spondylosis over the age of 50 yr. Cases and controls were matched for age and sex. Radiographs were taken according to a standardized protocol and DISH was classified using the Resnick criteria. Laboratory parameters and an interviewer-administered questionnaire were used to obtain data about exposure.

RESULTS

The mean ages of the populations with DISH and spondylosis were 65.2+/-8.8 and 65.0+/-9.1 yr respectively. Compared with controls, patients with DISH had a greater body mass index (27.8 vs 26.0 kg/m(2), P<0.05) and a higher serum level of uric acid (308 vs 288 micromol/l, P<0.05) and were more likely to have had diabetes mellitus (19.8 vs 9.1%, P<0.05).

CONCLUSION

DISH is clearly a distinct disorder with risk factors that distinguish it from other spinal degenerative diseases.

Identification of P-selectin glycoprotein ligand-1 as a useful marker in acute myeloid leukaemias

Immunophenotyping is considered to be less valuable in the diagnosis of acute myeloid leukaemias (AML) compared with acute lymphoid leukaemias. Here, we present data on the use of quantitative flow cytometry (QFC) of P-selectin glycoprotein ligand 1 (PSGL-1, CD162) and three-colour immunophenotyping including CD162 staining in the identification of myeloid precursors in AML. Analysis of normal peripheral blood (n = 20) and normal bone marrow (n = 5) samples and on 20 samples from de novo M1, M2, M4 and M5 AML patients demonstrated that PSGL-1 is differentially expressed on various mature and immature leucocyte subsets. It was found by QFC that neutrophils expressed 26500 +/- 4500 and monocytes 47200 +/- 9900 copies of PSGL-1 on their surface, whereas AML blasts from M1 and M2 AML patients expressed significantly less PSGL-1 (12 000 +/- 5300) than mature neutrophils (P < 0.001). In M4 and M5 leukaemias, however, the amount of PSGL-1 on monocytic precursors is displayed in a fairly broad range that is not significantly different from that of mature monocytes (P = 0.084). Using three-colour immunophenotyping PSGL-1-dim staining was co-expressed with CD7 and C34 positivity and PSGL-1 staining intensity on immature myeloid cells paralleled with CD45 expression. This would imply a differential expression of PSGL-1 during myeloid haematopoietic development and suggests that quantification of surface PSGL-1 may aid in differentiating myeloblasts from monoblasts by immunophenotyping in different AML subsets.

EBNA promoter usage in EBV-negative Burkitt lymphoma cell lines converted with a neomycin-resistant EBV strain

Latent Epstein-Barr virus (EBV) uses two alternative strategies to express the Epstein-Barr nuclear antigens (EBNAs). Resting normal B cells harboring latent virus and Burkitt's lymphoma (BL) cells use monocistronic messages generated from the Q promoter (restricted strategy). EBV-transformed immunoblasts express all EBNAs by using giant messages generated from the W/C promoter (full program). Whether the virus establishes the restricted program on primary infection of a BL cell (or its progenitor) or, alternatively, whether such cells are generated by phenotypic down-regulation from the immunoblast is unclear. We found previously that conversion of EBV-negative BL lines to EBV-positive sublines required repeated exposure to large virus doses. The converted sublines used the full program. However, the possibility that cells with a full program had a selective advantage during the long period of in vitro passage could not be excluded. We therefore infected EBV-negative BL lines with recombinant EBV carrying a neomycin resistance marker. Most convertants of the 12 lines tested were positive for YUK splicing, indicative of the full program, but some were also positive for the restricted QUK splice program. One convertant DG75 line showing both YUK and QUK was cloned and gave rise to stable QUK users. We conclude that EBV infection of established BL lines can give rise to subclones with either the full or the restricted program. The fact that all EBVs carrying BL lines use the restricted program in vitro may be a consequence of immunoselection.

The LZTFL1 gene is a part of a transcriptional map covering 250 kb within the common eliminated region 1 (C3CER1) in 3p21.3

Deletions on 3p have been described in a large number of human tumors, suggesting the presence of a tumor suppressor gene(s). Using the elimination test, we previously defined a 1-Mb segment from human 3p21.3 (C3CER1). Genomic sequencing allowed us to construct a transcription map covering 250 kb containing five genes. We have characterized a human leucine zipper containing gene, leucine zipper transcription factor-like 1 (LZTFL1), and its mouse orthologue (Lztfl1), which was also mapped to mouse chromosome 9F. The LZTFL1 gene has two transcript isoforms displaying alternative polyadenylation. We have localized the human orthologue of the yeast SAC1 (suppressor of actin) gene as well as characterized and mapped the mouse Sac1 gene. Furthermore, the XT3 gene was characterized, encoding a member of the Na(+)/Cl(-) neurotransmitter superfamily. It has been shown that the XT3 gene had an alternatively spliced brain-specific isoform, predicted to remove 1 of 12 putative transmembrane domains. The transcription map also includes the CC chemokine receptor 9 gene (CCR9) and the LIM domain containing gene 1 (LIMD1). This work partially defines the gene content of C3CER1 that is a prerequisite for delineation of its role in tumorigenesis.

Configuration and racemization determination of cysteine residues in peptides by chiral derivatization and HPLC: application to oxytocin peptides

An improved RP-HPLC method was developed for the determination of the configuration and stereochemical purity of cysteine residues in peptides. The method consists of oxidation of cysteine and cystine residues to cysteic acid, followed by hydrolysis and pre-column chiral derivatization with Val-Marfey's reagent.

Effect of myelopoietic and pleiotropic cytokines on colony formation by blast cells of children with acute lymphoblastic leukemia

The aim of this study was to see whether pleiotropic or myeloid hematopoietic growth factors, which do not stimulate normal lymphoid cells, can induce proliferation of blast cells of the acute lymphoid leukemia (ALL) of childhood. Bone marrow cells of 13 children with untreated ALL (nine common ALL, two myeloid antigen positive ALL and two early T-cell ALL) formed colonies of leukemic blast cells in primary methylcellulose cultures. Spontaneous growth was observed in three of 13 cases, whereas phytohemagglutinin-stimulated leukocyte conditioned medium (PHA-LCM), a conventional source of various natural human cytokines, induced colony formation in ten of 13 cases. A similar rate of responsiveness was seen with recombinant human granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and stem cell factor (SCF); a combination of these three cytokines induced colony formation in all cases studied. The effect of these growth factors on colony formation seemed to be dose-dependent in some cases. Of the stimuli studied, GM-CSF induced the smallest number of colonies, whereas the effects of G-CSF, SCF and PHA-LCM were similar in this respect. Combination of cytokines proved to be even more efficient in inducing clonal proliferation of leukemic lymphoblasts. In double combinations, G-CSF and GM-CSF as well as G-CSF and SCF were able to potentiate each other's effects. Triple combination of these cytokines mediated the most potent growth stimulus. Our results demonstrate that myeloid and pleiotropic cytokines are able to stimulate clonal proliferation of pediatric leukemic lymphoblasts. This may present a potential hazard to children with ALL while on adjuvant therapy with hematopoietic growth factors. In vitro colony assays performed prior to or in parallel with the administration of hematopoietic growth factors to ALL patients may help to forecast their possible effects on leukemic cells in vivo.

Proteins associated with the promyelocytic leukemia gene product (PML)-containing nuclear body move to the nucleolus upon inhibition of proteasome-dependent protein degradation

Several recent findings have indicated that the promyelocytic leukemia gene product (PML) oncogenic domains (PODs) are involved in proteasome-mediated degradation of ubiquitinated proteins. We wanted to examine the intracellular distribution of PML protein in the presence of a proteasome inhibitor. We used high-resolution microscopy to study the distribution of PML protein and other POD-associated proteins along with the proteasomes themselves under normal conditions and in cells treated with the proteasome inhibitor, MG132. Inhibition of the proteasomes in MCF-7, HeLa, and IB-4 cell lines resulted in a radical redistribution of the POD-associated proteins PML, Sp100, and SUMO-1. After 6-10 h of MG132 treatment, PML, Sp100, and SUMO-1 were no longer detectable in the PODs and accumulated mainly in the nucleolus. Moreover, MG132 treatment changed the cellular distribution of the proteasomes. Interestingly, this included the accumulation in euchromatin areas of the nucleus and within the nucleoli. Several non-POD-associated proteins did not change their cellular distribution under the same conditions. The accumulation of POD-associated proteins and proteasomes in the nucleoli of MG132-treated cells indicates that these proteins may target the nucleoli under normal conditions and that the nucleolus may have a function in the regulation of proteasomal protein degradation.

Some metabotropic glutamate receptor ligands reduce kynurenate synthesis in rats by intracellular inhibition of kynurenine aminotransferase II

Some metabotropic glutamate receptor (mGluR) ligands, such as quisqualate, L-(+)-2-amino-4-phosphonobutyric acid (L-AP4), 4-carboxy-3-hydroxyphenylglycine (4C3HPG), and L-serine-O:-phosphate (L-SOP), reduced the formation of the endogenous excitatory amino acid receptor antagonist kynurenate in brain and liver slices. The use of novel, subtype-selective mGluR agonists and antagonists excluded a role for any known mGluR subtype in this effect. The reduction of kynurenate formation was no longer observed when slices were incubated with the active mGluR ligands in the absence of extracellular Na(+). trans-Pyrrolidine-2,4-dicarboxylate (trans-PDC), a broad-spectrum ligand of Na(+)-dependent glutamate transporters, was also able to reduce kynurenate formation. Quisqualate, 4C3HPG, L-AP4, and L-SOP did not further reduce kynurenate formation in the presence of trans-PDC, suggesting that the two classes of drugs may share the same mechanism of action. Hence, we hypothesized that the active mGluR ligands are transported inside the cell and act intracellularly to reduce kynurenate synthesis. We examined this possibility by assessing the direct effect of mGluR ligands on the activity of kynurenine aminotransferases (KATs) I and II, the enzymes that transaminate kynurenine to kynurenate. In brain tissue homogenates, KAT II (but not KAT I) activity was inhibited by quisqualate, 4C3HPG, L-AP4, L-SOP, and trans-PDC. Drugs that were unable to reduce kynurenate formation in tissue slices were inactive. We conclude that some mGluR ligands act intracellularly, inhibiting KAT II activity and therefore reducing kynurenate formation. This effect should be taken into consideration when novel mGluR ligands are developed for the treatment of neurological and psychiatric diseases.

Protective and destructive immune reactions in apical periodontitis

Apical periodontitis is initiated primarily by the mixed microflora of infected root canals. Continuous flow of bacteria and their products through the apical foramen induces influx, activation and coordinated interaction of immune-inflammatory cells within the periapical area. Successful mobilization of host defense mechanisms prevents abundant extraradicular bacterial invasion. However, anti-infective effector mechanisms are not restricted to killing the invading microorganisms but also destroy normal tissue components and induce bone absorption, resulting ultimately in the loss of the affected teeth. Moreover, autocrine and paracrine loops of stimulation may lead to the perpetuation of the local inflammatory lesion and may also alter the function of remote tissues and organs. This review attempts to summarize current knowledge about the pathogenic mechanism of apical periodontitis, focusing on the formation of a special granulation tissue that effectively fights bacteria originated from the infected pulp chamber and, by exerting this protective function, also contributes to harmful local and distant events. The dynamic equilibrium between defensive and destructive mechanisms may provide a pathobiological basis for better understanding of clinical signs and symptoms of various forms of apical periodontitis lesions and influence treatment strategy and practice.

Differential in situ distribution of interleukin-8, monocyte chemoattractant protein-1 and Rantes in human chronic periapical granuloma

In situ distribution of three prototype chemokines interleukin (IL)-8, monocyte chemoattractant protein (MCP)-1 and Rantes was determined in chronic human periapical granulomas by immunohistochemistry using monoclonal antibodies. IL-8 was found primarily in the cytoplasm of the Malassez epithelial cells. MCP-1 immunoreactivity was confined to the endothelial cells that lined small venules. Each of the three investigated chemokines, including Rantes, exhibited a characteristic binding pattern to the extracellular matrix of the lesion. The observed chemokines may play a role in establishing the cellular composition of chronic apical periodontitis, thus augmenting the intensity of local inflammation and tissue damage.

A novel gene containing LIM domains (LIMD1) is located within the common eliminated region 1 (C3CER1) in 3p21.3

Chromosomal deletions on 3p have been described in a large number of human tumors, suggesting the presence of a tumor suppressor gene(s). Using an experimental system, called the elimination test, we previously identified a 1 Mb segment, the common eliminated region 1 (C3CER1). C3CER1 was also covered by a PAC contig. Using the sequence of two overlapping PACs from C3CER1, we localized the human KIAA0028 cDNA, encoding the precursor of mitochondrial leucyl-tRNA synthetase. We also characterized a novel human LIM domain-containing gene (LIMD1) and its mouse ortholog (Limd1). LIM domains consist of a cysteine-rich consensus sequence containing two distinct zinc-binding subdomains, which mediate protein-protein interactions. The predicted protein sequences of the human and mouse genes reveal three LIM domains located at the C-terminal end, which indicates that they belong to the group 3 of the gene family encoding LIM motifs. We characterized the genomic structure of the human LIMD1 gene and assigned the mouse Limd1 gene to the chromosome 9F subtelomeric region. Both genes are ubiquitously expressed at the mRNA level. The LIM motif has been previously identified in many developmentally important factors from various eukaryotes. These factors have been shown to play a role in intracellular signaling, transcriptional regulation and cellular differentiation during development. The human C3CER1-located LIMD1 gene should therefore be further studied for its possible role in tumor suppression.

[Analysis of activated cells in apical granuloma]

The ratio and in situ distribution of CD3+ T-lymphocytes, CD4+ and CD8+ subsets, CD14+ macrophages, CD56+ natural killer cells and CD25+ activated T-lymphocytes and CD68+ activated macrophages were determined in 20 chronic peripical granulomas by immunohistochemical method using monoclonal antibodies. CD3+ T-lymphocytes made up about 50% of the mononuclear cells. CD14+ macrophages were distributed all over the area but their proportion was much less that that of the T-lymphocytes. CD56+ natural killer cells made up a small proportion of the cells. The major proportion of the T-lymphocytes and macrophages were in activated stage within the lesion.

Analysis of NotI linking clones isolated from human chromosome 3 specific libraries

We have partially sequenced more than 1000 NotI linking clones isolated from human chromosome 3-specific libraries. Of these clones, 152 were unique chromosome 3-specific clones. The clones were precisely mapped using a combination of fluorescence in situ hybridization (FISH) and hybridization to somatic cell or radiation hybrids. Two- and three-color FISH was used to order the clones that mapped to the same chromosomal region, and in some cases, chromosome jumping was used to resolve ambiguous mapping. When this NotI restriction map was compared with the yeast artificial chromosome (YAC) based chromosome 3 map, significant differences in several chromosome 3 regions were observed. A search of the EMBL nucleotide database with these sequences revealed homologies (90-100%) to more than 100 different genes or expressed sequence tags (ESTs). Many of these homologies were used to map new genes to chromosome 3. These results suggest that sequencing NotI linking clones, and sequencing CpG islands in general, may complement the EST project and aid in the discovery of all human genes by sequencing random cDNAs. This method may also yield information that cannot be obtained by the EST project alone; namely, the identification of the 5' ends of genes, including potential promoter/enhancer regions and other regulatory sequences

Identification of new tumor suppressor genes based on in vivo functional inactivation of a candidate gene

As a step towards developing a new functional test for the identification of tumor suppressor genes, human wild type and mutant RB genes were expressed in the mouse A9 fibrosarcoma cell line under the transcriptional regulation of the tetracycline repressor using two new vectors: pLNCtTA and pETI. Following passage of the transfectants in immunodeficient SCID mice, the wild type RB gene was deleted or functionally inactivated already after the first passage in all 20 tumors tested. In contrast, a non-functional mutant RB gene was maintained in all 10 tumors studied. These results suggest that tests for the identification of tumor suppressor genes may be based on their functional inactivation in vivo, rather than on growth suppression.

Human herpesvirus 8 in hematologic diseases

Human herpesvirus type 8 (HHV-8), also known as Kaposi's sarcoma-associated herpesvirus (KSHV) is a new member of the g-herpesvirus family. It is an unusual herpesvirus in that it carries a large number of genes that encode oncoproteins or cell signaling proteins. In addition to being the causative agent of both HIV-associated and non-HIV-associated Kaposi's sarcoma this DNA tumor virus has been implicated in the pathogenesis of several diseases. These include multiple myeloma (MM), Waldenstöm's macroglobulinemia (WM), multicentric Castleman's disease (MCD), body cavity-based lymphoma (BCBL), and various other conditions such as sarcoidosis and pemphigus. While the causative role of the viral infection is fairly certain in the development of BCBL and multicentric Castleman's disease, HHV-8 may act through a different mechanism to induce plasma cell malignancies. It has been suggested though the finding is still controversial - that infection of bone marrow stromal dendritic cells by HHV-8 might be a key factor in the etiology and pathogenesis of monoclonal gammopathies. The aim of this review is to provide a short introduction into the tumorigenic potential of HHV-8 as well as to detail the available data and possible mechanisms on the involvement of this virus in different hematologic diseases.