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Body
Positive Staffordshire
The long awaited return of Henry Grahame Smith to Stoke was well worth the time and effort it took. Henry is a charismatic leader with an endearing laid back approach well able to cope with a diverse range of personalities and with people at different stages of HIV progression. He is happy to stop and answer questions at any point. He makes use of excellent visual aids and like all good teachers uses appropriate stories, parables and anecdotes that make complicated medical information easy to understand. In the morning we looked at the immune system and how it works. The different types and functions of leukocytes (white blood cells) that make up the immune system became clear with the help of overhead projections of sea creatures. A killer shark represented a CD8 cell whilst the CD4 was an intelligent dolphin. Phagocytes were likened to the Pacman in the electronic game who gobbles up everything in front of him. Another effective illustration was a reference to the film “The Incredible Journey” in which a group of scientists are shrunk to microscopic size to perform an operation inside a human body. An explanation of the life cycle of the HIV virus (about 1.2 days) led on to a look at the way the HIV virus attaches itself to CD4 cells and replicates. By lunchtime we had become acquainted with the double spiral building blocks of human DNA and the enzymes that enable the single strands of the HIV RNA to replicate and produce new HIV infected cells as well as the types of anti HIV drugs that inhibit this progression of HIV infection. After a superb buffet lunch provided by Staffordshire Buddies we went on to explore The nature and significance of blood tests including CD4 Counts and Viral Loads. We learned that the amount of blood taken, although it may seem like an armful, is really quite small and that readings represent the number of cells in a millilitre of blood (less that a pin prick). It was a surprise to discover that only 2% of CD4 cells are present in the blood, the rest are in tissues such as lymph nodes. We discovered that people can have naturally high or low CD4 counts and that a CD4 percentage is a more useful indicator of HIV progression than a CD4 alone. Another important measurement is the ratio between CD4 and CD8 count. How resistance develops was the major theme that followed. Henry used clear diagrams showing the peaks and troughs of effective drug interaction to show the points at which mutations of drug resistant virus occurred. This was brilliantly supplemented with an analogy of fruit flies in a crop of sugar cane that mutated to survive insecticide. We were left with a clearer understanding of why it is important to take drugs at the right time and not to miss doses. An explanation followed of how Phenotypic and Genotypic tests detected viral mutations that could indicate drug resistance. We discovered that the test needed a detectable viral load of at least 1,000 copies and were most useful on starting therapy for the first time (you could have been infected with HIV that is resistant to one or more of the drugs) The other occasion when resistance tests might be helpful is when drugs fail - though it should be noted that poor absorption, drug interactions and missing doses are other possible causes for drug failure. It is most important in the second instance that the resistance test is done whilst you are still taking a failing combination. One of the best things about Henry’s workshop is the opportunity to ask questions and this happened throughout the day. Some of the ones that stood out were those that revealed that individuals can naturally have very high or low CD4 counts and that each one of us has a different rate of metabolism. This last point showed that there was a great deal of sense in employing TDM (Therapeutic Drug Monitoring) a relatively inexpensive test that by measuring drug levels against known optimum concentrations. This would overcome the risks of relying on predetermined dosing for all patients (Particular useful in treating children). As Henry pointed out ‘one dose for all’ is not necessarily the best dose for some. Those who were unable to attend the workshop can still enjoy the benefit of Henry’s wisdom as the areas covered in the workshop appear in articles he writes for “Positive Nation” and the new magazine “+ ve” NAM provides an excellent range of treatment information material and these are free for people affected by HIV. To find out more telephone 020 7627 3200 M |
