We thank Celgene for providing an unrestricted educational grant which made possible these updates from Stockholm.
This is a summary of the events of September 5, 1999 at the VII International Workshop.
HHV-8 in Multiple Myeloma
This session dealt with the controversial issue of the potential role Kaposi's Sarcoma-related Herpesvirus (HHV-8) in multiple myeloma. This remains an area of serious controversy and this session's lack of consensus on the presence or potential role of the virus reflects this.
- Dr. Frank Niepel of Germany reviewed epidemiological background of this virus. While it was initially an object of some controversy, it is now accepted that HHV-8 is present in patients with a number of diseases like primary effusion lymphoma, Castleman's disease and Kaposi's Sarcoma (KS). There remains controversy as to whether the virus can be found in semen, prostatic glands and skin tumors other than KS and multiple myeloma. There also remain questions about whether the virus plays a role in the development of the diseases with which it is typically found, like KS. Studies have shown a marked increase in HHV-8 in patients exhibiting high risk sexual behavior. However, there is as yet no definitive proof that this virus can be transmitted sexually.
- Dr. James Berenson of the UCLA presented an update on prior findings about the potential role of HHV-8 in the pathogenesis (development) of multiple myeloma. It has already been shown that IL-6 is up-regulated (produced in higher than normal quantities) in the bone marrow in the presence of myeloma cells. This upregulation is also present in KS. The HHV-8 virus produces a viral homologue (equivalent) of IL-6. This led to investigation of the possibility that HHV-8 could be present in the stromal (bone marrow) cells and possibly playing a role in the development of the disease. The virus was detected in cultured cells as well as fresh bone marrow and peripheral blood cells of myeloma patient/ Ot was [resemt om 44 pf 52 mm patients, 2 of 7 MGUS patients, and 0 of 8 solitary plasmacytoma patients. This work was repeated on patients from other parts of the US, Europe, Asia and the middle east. It was noted that HHV-8 was rarely detected (2% vs. 70% for patients) in the peripheral blood of myeloma patient's family members, suggesting that the risk of sexual transmission is not a cause for concern. There have been problems reproducing these results in other labs. Studies were done, blinded, with two different labs and three sets of primers. There was agreement in about 98% of the cases. Dr. Berenson discussed the various assays available for detecting the virus and specific changes to the genetic sequences of the virus that appear to be specific to myeloma (seem to occur uniquely and frequently in myeloma patients)
- Dr. Ruth Jarrett of the UK reviewed data on testing for the presence of HHV-8 in the blood of myeloma patients. In a study where blood from 78 myeloma patients and 37 normal controls was tested for the presence of the virus, there was no evidence found of the presence of HHV-8.
- Dr. K Tarte of France discussed her view that HHV-8 is not causally associated with (i.e., does not cause) multiple myeloma. The usage of nested PCR, which dramatically amplifies, through repeated cycles, the material in the original sample is a concern because it can generate false positives. A series of studies were done with multiple laboratories and the conclusion of all of these studies was that there is no increased serioprevalance (frequency of people with the virus present in their blood) for myeloma patients versus the rest of the population. The conclusion was that there is no association of KSHV (HHV-8) with multiple myeloma.
- Dr. Quing Yi of the University of Arkansas Medical School presented work done to examine dendritic cells for the presence of KSHV. No evidence could be found for the presence of KSHV in these cells for any of the 10 patients tested. This was the conclusion despite multiple methods used to detect the potential presence of the virus.
- Dr. Erik Weimer of Rotterdam presented work looking for the presence of HHV-8 in mononuclear cells of myeloma patients. The ORF 26 signature of the virus was found in one myeloma patient and none of the controls. The conclusion was that the virus could be found in 30% of the myeloma patients and none of the controls. When the ORF 26 signature could be detected, the ORF K9 signature could also be detected.
- Dr. Moosa Patel of the University of Witwatersrand discussed issues about HHV-8 and multiple myeloma. Multiple myeloma is the most common hemopoietic malignancy in South Africa. Looking at 27 newly-diagnosed myeloma patients and 19 control patients, nested PCR was used to look for the ORF26 signature. The majority of the patients had advanced stage disease. 40% of the adherent cell cultures were positive. None of the controls were positive. The significance of these findings was characterized as unclear, given the small number of patients and the high seroprevalence of JSHV in the general population in South Aftrica. Further studies are planned to get more clartiy on this issue.
- Dr. Rask of Denmark presented findings that the presence of HHV-8 could not be detected in Danish patients with untreated, active mutiple myeloma. 15 patients, most with advanced disease were studied, using bone marrow and peripheral blood cells. Nested PCRs were performed using these fresh samples and with longer-term stromal (bone marrow) cell cultures. Looking for three of the characteristic genetic signatures of the virus, it could not be detected in any of the Danish patients studied.
- Dr. Thomas Rasmussen of Denmark discussed findings using semi-nested PCR on a group of Danish and Norwegian patients looking for KSHV infection. Tests were performed on 7 patients, using fresh bone marrow cells and dendritic cell cultures. No virus was detected in the fresh marrow cultures. 2 of 11 patients were positive in the cultured cells, which were detected after 2x45 cycles of PCS, which stretches the limits of PCR amplification and has a higher risk of false positives. The conclusion was that these patients were not infected with KSHV.
A roundtable discussion followed. Dr. Anderson posted five questions to be addressed by the group:
- Is the association with multiple myeloma pathogenic (causing the disease) or opportunistic (a consequence of having myeloma)?
- Is activation of :MM-HHV-8" prodrome or iatrogenic consequence?
- Is the HHV-8 detected in myeloma the same as KSHV or is it an "MM-HHV-8 subtype"?
- Which cells are infected? (stromal, hematopoietic or dendritic cells?)
- How can we standardize methodology and diagnostic criteria?
Dr. Peter Bieberfeld reviewed the experience in looking at the potential association of the Epstein-Barr virus with Burkitts Lymphoma. In that disease, it was easier to prove the existence of the virus in the patients because it can be imaged on an electron microscope. However, in Burkitts, the virus was found only in patients in Africa and not in Burkitts patients elsewhere in the world, indicating that the disease could clearly develop without the virus. Dr. Bieberfeld counseled the group to take the steps necessary to settle the question of whether or not the virus is present, including having the proponents of the various positions exchanging materials and repeating their tests.
- Dr. Brian Durie of Cedars-Sinai Comprehensive Cancer Center presented findings of an RNA moleculatr markers for myeloma in the plasma (blood) of myeloma patients. A 713 nucleotide sequence homologous to chromosome 22q11.2 was found in the blood of patients with active myeloma, which is largely absent from those in remission, those with MGUS and healthy controls. Analysis of the sequence shows that it contains ALU sequences, which are recombinant elements (DNA which can transcribe into RNA and reinsert itself into other locations in the genome). The possibility was discussed that transcription could be triggered by one or more events, such as toxic exposures, viruses or physical stress. Work is currently underway analysing the RNA material using electron microscopy, purification and staining to understand its nature and composition. They hypothesis was advanced that this material could be "voyager RNA", which Prof. Luc Montagnier has postulated as a potential infectious agent for viruses. Further studies are needed to understand more fully the nature of this material and its potential role in the pathogenesis of multiple myeloma.
Closing the Workshop
Dr. Mellstedt led a panel discussion about future directions in myeloma research. The participants expressed their optimism at all of the good progress that had been discussed during the workshop. They urged their colleagues to build bridges between the clinicians and the basic scientists, to ensure that the best ideas could be applied to best advantage. It was suggested that new approaches looking at targeting the bone marrow microenvironment with an eye toward interfering with myeloma cell growth as opposed to targeting the myeloma cells could prove productive. It was also suggested that more focus be placed on long-time survivors, with an eye towards understanding, at a molecular level, the reasons for sustained stable remissions. They also discussed the importance of reaching outside of the myeloma community to other disciplines to help deal with some of the more challenging areas brought up in the latest research, including the role of viruses and immunotherapy.
The participants look forward to the next workshop to be held in Banff in May, 2001.