Compiled and edited by Laurence Gibson
Use of cannabis does not seem to adversely affect CD4 count or viral load
in HIV-infected patients, a new study has found.
The University of California report found no harmful changes in HIV levels in the participants when they either smoked marijuana or took the oral cannabinoid dronabinol.
In HIV-infected patients, marijuana has been used as an appetite stimulant and as a treatment for the nausea associated with some antiretroviral medication. But, in the past, concern has been raised that such therapy could have a harmful effect on disease status.
This 25-day study included 62 infected people on antiretroviral regimes including a protease inhibitor.
The subjects were divided into three groups: 20 smoked marijuana, 22 received dronabinol, and 20 received an oral placebo.
Researchers measured changes in HIV levels in the blood of the volunteers as well as their CD4 counts. In all three groups, patients with detectable levels of HIV had no change in the levels of virus in their blood.
However, CD4 cell counts actually increased about 20 per cent for both the groups that received cannabis - while there was no change in the CD4 of the placebo group.
“The change in lymphocyte counts for the group that smoked marijuana is intriguing. At a minimum, it contradicts findings from previous studies suggesting that smoked marijuana actually suppresses the immune system,” said study author Dr Donald Abrams, a professor of clinical medicine.
“People with HIV are a vulnerable population, so successfully addressing the safety concerns allows us to move on to effectiveness studies, three of which are currently under way here,” he said. Laurence Gibson
This month a study by the Medical Research Council aims to find out if cannabis can help to relieve pain - where the patients actually receive capsules containing standardised cannabis extract.
In the maiden voyage for a novel technique to study the disease, researchers have found that the genes underlying HIV patients’ immune systems can predict their risk of progressing to Aids.
The new analysis showed the virus is less likely to progress in patients bearing rare immune system variants - rather than with those with more common gene variants.
The researchers said the finding clarifies the interaction between HIV and patients’ immune defences and provides information that may ultimately help doctors tailor treatments to individual patients.
“Specific combinations of alleles [variations of a gene that differ slightly in structure and function] that humans carry, appear to protect against HIV,” said Thomas Kepler, from Duke’s University in Chicago.
“HIV-infected people who carry particular rare gene variants have much lower viral loads than the other patients do,” he continued.
The study focused on 996 men, 562 of whom were HIV positive. The researchers genetically screened participants’ blood samples for two immune system genes, HLA-A and HLA-B.
HLA molecules orchestrate the response of the T-cells.
As immune system alleles are notoriously diverse, it was necessary for Kepler and his team to devise a novel statistical method to divide patients into disease progression groups.
“The method allowed us to exhaustively go through all possible gene partitions and assign a score to each, while avoiding the pitfalls of traditional methods of analysis,” Kepler stated.
The analysis of the patients revealed that “greater protection against HIV was afforded by rare immune system alleles” according to Kepler.
“This suggests that HIV has adapted to attack the dominant alleles in the population. In other words, the virus goes after the bigger target,” said Kepler.
By screening patients’ immune systems, doctors may eventually be able to identify those at the greatest risk of developing Aids - and prescribe accordingly.
Wide publicity has recently heralded the licensing of T-20, or Fuzeon, the first of a new class of HIV drugs called fusion inhibitors. They block HIV in a new way, by preventing it entering cells in the first place.
However T-20 has to be injected twice a day, and the race is on to develop fusion inhibitors that can be taken in pill form.
The drug company Bristol-Myers Squibb recently announced promising pre-clinical results for a substance called BMS-378806. This works at an earlier stage of fusion than T-20, preventing the gp-120 protein - the ‘knobs’ on the surface of HIV - from making contact with the CD4 molecules on the surface of immune cells. This is the very first stage of the virus infecting a cell. Drugs further along in development block the next stage of HIV fusion when it links to the ‘co-receptor’ CCR5 or CXCR4 molecules also on cells. T-20 blocks a further stage in the process, where HIV ‘injects’ itself through the cell membrane.
But top UK HIV researchers Drs Aine McKnight and Robin A Weiss from University College London noted: “While anti-HIV compounds that block co-receptors and membrane fusion are in preliminary clinical trials, BMS-378806 is the first small molecule to block the gp120-CD4 binding event.”
Studies in rats, dogs and monkeys showed that BMS-378806 had “good oral bioavailability and a clean safety profile,” according to Dr Pin-Fang Lin of BMS. The drug appeared active against a wide range of different HIV viruses, including ones resistant to current drugs.
The drug is thus the first proof that an oral blocker of the gp120 molecule can work. However, gp120 is the most genetically variable of all HIV’s components - and resistance to the drug itself would therefore arise quickly if it were not used as part of effective combination therapy.
Taking antiretroviral treatment significantly improves the lives of young people, a new US study has found.
In the groundbreaking study, 258 participants were obtained from clinical care sites, street outreach programmes and community announcements in New York and Los Angeles.
The subjects, all aged between 14 and 29, answered questions about their medications/adherence, their health status, sexual behaviour, substance use, life expectancies, negative life events, mental health symptoms, and their quality of life.
54 per cent of the sample were currently using HAART, and 77 per cent had used HAART at some point.
Those that were not users of HAART (non-users) cited fear of side effects or fear that HAART would make them feel worse.
But the study found that HAART users were less likely than non-users to have more than nine sexual partners. Thus, users also reported lower levels of STDs over their lifetimes.
Users reported lower substance abuse rates and said they anticipated a longer life than non-users.
Users were less likely than non-users to have spent time in jail and reported higher levels of social support.
Most importantly, all the users said they also expressed higher levels of life satisfaction than non-users.
Two new studies, one from London and one from California, last month claimed
the internet is becoming the preferred way for men to meet men for sex - but
safe sex is often forgotten, leading to higher rates of diseases.
“What we are hearing from the participants in terms of why they are using the Internet is that they find it amazingly easy, efficient and low cost, and that there are a wide range of partners available to them,” said Gregory Rebchook, a researcher from California.
Recent public health surveys of gay men with syphilis, in London and California, revealed that one-third of them had found partners online.
In the California study, the figure was one-eighth just two years ago.
“The internet is now more commonly reported than saunas, sex clubs or bars and clubs as a venue for meeting partners,” said Terrence Lo, from the Department of Health.
Both studies clearly demonstrate the health dangers that internet dating can pose.
