Do CD4 Counts Matter After Starting Treatment? An HIV Doc Responds

Joel Gallant, M.D., M.P.H.
Joel Gallant, M.D., M.P.H.

One of the main goals of HIV treatment is to get your viral load below 50 copies/mL where it is considered "undetectable." But what about your CD4 count? Currently, all of the five major international HIV treatment guidelines recommend starting treatment for all individuals living with HIV, regardless of CD4 count. But does CD4 count matter after you start treatment? Why do we continue to monitor CD4 counts if they're not as important as viral loads?

On his personal Tumblr, Joel Gallant, M.D., M.P.H., an HIV doctor at Southwest CARE Center in Santa Fe, New Mexico, answers questions from people living with HIV who are concerned about a number of issues, including starting treatment and CD4 counts.

On May 8, 2016, an anonymous user asked:

I know you and others say to ignore CD4 count, once on meds. However, I'm not quite sure why being undetectable changes why CD4 count is not important. I began meds four months ago and my CD4 count and percentage have not changed from 500 and 21%. I know some see their [numbers] begin to jump right away, while others don't. I also know someone with 900 isn't necessarily better off than someone with 300. I've always read 21% is on the edge of having a fairly functioning system. Why does being undetectable change that, besides not making it worse?

Gallant answered:

We don't pay attention to CD4 counts when you're on therapy because there's nothing you can do with the results. Unless the count is low enough to require opportunistic infection prophylaxis, you can only control your viral load, keeping it undetectable. Beyond that, you have no control over your CD4 count, and there are no interventions you would make based on the number.

In your own case, you're worried about why your normal CD4 count is not higher. But a normal count is a normal count. There's no evidence that 900 is healthier than 500.

So there you have it -- although CD4 counts can be meaningful, there's not much you can do to change them. What do you think? Do you closely monitor your CD4 counts and, if so, why? Discuss in the comments section below.

Joel Gallant, M.D., M.P.H., is the associate medical director of specialty services at Southwest CARE Center in New Mexico. You can ask him a question directly on his Tumblr page, Ask Dr. Joel.