HIV and cancers

The importance of maintaining a strong immune system when taking HIV treatment has been underlined by a new Dutch study.

It showed that patients taking antiretroviral therapy who had a CD4 cell count below 200 had an increased risk of some non-AIDS-related cancers.

There was also some evidence that the risk was increased for patients with a CD4 cell count below 350.

Non-AIDS-related cancers are an increasingly important cause of serious illness and death in people with HIV.

There are a number of possible reasons for this.

These include the natural ageing process – thanks to HIV treatment, many people are now living long enough to develop the cancers associated with older age.

Among people with HIV, there is a high prevalence of some risk factors that are especially associated with some cancers – most notably smoking.

Infections that are associated with certain cancers are also common in people with HIV – for example some strains of the human papillomavirus (HPV) that are associated with anal and cervical cancer.

Having a weak immune system may also increase the risk of cancers.

Dutch researchers wanted to find out if factors related to HIV and infections such as HPV and hepatitis were increasing the risk of non-AIDS-related cancers for people taking antiretroviral treatment.

They looked at the medical records of over 11,000 people who started HIV treatment between 1996 and 2009.

A total of 236 non-AIDS-related cancers were diagnosed, and 43% of these were related to infections.

There were 35 cases of anal cancer, and this was associated with longer duration of time with a CD4 cell count below 350.

Liver cancer was associated with infection with the hepatitis B virus, older age and alcohol abuse.

Further analysis showed that, overall, the longer a person had a CD4 cell count below 200, the higher their risk of non-AIDS-related cancers caused by infections.

The researchers believe that their findings emphasise the importance of starting HIV treatment promptly.

They also call for patients to be screened for cancers in their routine HIV care, and stress that HIV-positive people should be vaccinated against hepatitis B.

HIV treatment

The type of cell HIV uses to attach itself in the body is associated with the success of HIV treatment, according to a recent study.

One of two co-receptors is used by HIV to latch onto immune system cells. This is called HIV tropism.

In most people, virus uses the CCR5 co-receptor, but in patients who’ve had HIV for a long time, especially if they have a damaged immune system, HIV often uses a co-receptor called CXCR4.

In patients not taking HIV treatment, virus using the CXCR4 co-receptor has been associated with faster HIV disease progression.

The anti-HIV drug maraviroc (Celenstri) works by blocking the CCR5 co-receptor, and all patients should be tested to see which co-receptor their HIV uses before starting therapy with this drug.

The latest research involved 569 patients who were starting HIV treatment (none were taking maraviroc).

Overall, 14% of patients had virus that used the CXCR4 co-receptor.

These patients had a lower CD4 cell count and higher viral load at baseline than those whose virus used CCR5.

One year after starting treatment, patients with CXCR4 virus were significantly less likely to have an undetectable viral load than those with CCR5 virus.

However, there was no evidence that co-receptor type affected CD4 cell count.

“In antiretroviral-naïve patients beginning antiretroviral therapy, baseline HIV-1 tropism seems to be an independent predictor of virologic response,” conclude the investigators, adding “this observation may have important clinical implications for the monitoring of antiretroviral therapy and interpretation of comparative trials.”