Syphilis
The sexually transmitted infection syphilis has made a resurgence in the past five years, both in Europe and North America, and in Asia.
In Europe and North America the syphilis resurgence has been particularly noticeable among HIV-positive gay men, leading to a recent UK recommendation that all HIV-positive patients should be screened for syphilis every three months.
Several studies have now shown that syphilis can cause increases in viral load – the amount of HIV in the blood – and declines in the CD4 cell count.
A large Spanish study has now shown that the people most vulnerable to a large CD4 cell decline are those who have higher CD4 counts when they contract syphilis. CD4 cell counts fell by around 100 cells when patients in the study contracted syphilis, but rose again after syphilis was successfully treated.
Syphilis can be contracted through unprotected anal or vaginal intercourse, but also through oral sex. It can also be transmitted by close physical contact with syphilitic rashes and lesions, which can be anywhere on the body, and from contact with blood.
Early syphilis infection will result in a small lesion called a chancre that may not be noticeable if it is on a mucous membrane inside the body, like the anus, vagina or mouth.
Regular blood tests are the only way to be certain that you do not have syphilis – if your clinic does not routinely test you for syphilis at every clinic visit, you should ask for a regular sexual health screen.
Syphilis must be treated with injections into buttocks, and many clinics in the UK think that the most effective treatment is a course of 17 days of injections of procaine penicillin.
Syphilis treatment is more likely to fail in HIV-positive people for reasons that are not entirely understood. However, one reason for treatment failure pinpointed in a recent study was the failure to return for follow-up blood tests. If syphilis is not fully eradicated from the body, there may be a higher risk for HIV-positive people of developing nervous system symptoms like headache or even meningitis.
Antiretroviral treatment and the kidneys
HIV can cause damage to the kidneys, especially in people of African origin. Several studies presented at last month’s Conference on Retroviruses and Opportunistic Infections showed that kidney function tends to improve when people start taking antiretroviral therapy, but that HIV-positive African-Americans remain at higher risk of chronic kidney disease requiring dialysis treatment or kidney transplant when compared to African-Americans without HIV.
Several studies presented at the conference showed that treatment with the antiretroviral drug tenofovir (Viread, also contained in Truvada ) can cause a modest decline in kidney function, especially when combined with a protease inhibitor that is boosted by a small dose of ritonavir.
At present these modest declines in kidney function have not been shown to translate into long-term harm, but it is important that kidney function is tested regularly in anyone taking antiretroviral therapy, so that drug doses can be adjusted if any decline in kidney function is detected. Kidney function is normally measured by the amount of creatinine in the urine.
Declines in kidney function on tenofovir treatment seem most likely to occur in people who already have some impairment of their kidney function.
How long does the immune system take to return to normal levels on HIV treatment?
Antiretroviral therapy with three potent drugs can reduce levels of HIV in the blood to undetectable levels within 16-24 weeks of beginning treatment. However, it takes much longer for the immune system to replenish the immune system cells lost as a result of HIV infection.
Several studies presented last month at the Conference on Retroviruses and Opportunistic Infections looked at how long it takes for the immune system to regenerate CD4 lymphocytes, the type of cells that are lost as HIV levels in the blood rise.
Treatment guidelines around the world recommend that treatment should start before the CD4 cell count falls below 200 cells/mm3, the level at which people begin to have a much higher risk of serious illnesses or death as a result of immune suppression.
Healthy adults without HIV infection will have a CD4 cell count anywhere between 500 and 1200, on average.
After HIV treatment begins an HIV-positive person’s CD4 cell count may rise by up to 100 cells in the first year. Recent US research had suggested that people who started treatment with higher CD4 cell counts (above 350) were much more likely to experience a rise in CD4 count to near-normal levels.
However, European research presented at CROI did not show this effect: everyone who remained on treatment with fully controlled viral load could potentially reach a normal CD4 cell level eventually, if treatment continued to be fully effective.
A major Swiss study showed that young people, women, and those who started treatment with higher HIV levels had the biggest CD4 cell gains. People who started treatment at very high CD4 counts, those who were taking efavirenz (Sustiva) or nevirapine (Viramune) rather than a protease inhibitor, and those taking tenofovir (Viread) when compared to d4T (Zerit) had smaller CD4 cell gains.
TB in the UK
HIV-positive Africans living in the UK are two and half times more likely to develop tuberculosis than other HIV-positive people, a review of all the HIV-positive TB cases has found.
This is not altogether surprising, since people who have lived in Africa are much more likely to have been exposed to TB in the past. The TB germ can lie dormant for many years before becoming activated, but can be detected in the majority of HIV-positive people with a skin test. Active TB develops when the immune system declines. It can be prevented by giving preventative treatment with isoniazid, a drug also used in the treatment of active TB.
The study also showed that HIV-positive Africans are often being diagnosed with TB very soon after being diagnosed HIV-positive, and at very low CD4 cell counts.
Many of these TB cases could be prevented, say doctors, if people were diagnosed with HIV earlier. Antiretroviral therapy could be started before the immune system declines to a level at which TB becomes highly likely. People with very low CD4 cell counts, and a high risk of developing TB, could receive isoniazid treatment for a period.
This is one reason why learning your HIV status can protect you against the risk of illness caused by the virus.