Can Bugs Increase CD4 Cells?

This question and answer originally appeared on Nelson's "Ask the Experts" forum on Nutrition and Exercise.


Hello, some studies show that probiotic yogurt can increase CD4 counts, but others show risks to those with compromised immune systems taking probiotics. What are your thoughts? I have been on HIV therapy for nearly 3 years and have not yet achieved a consistent CD4 count over 200. My % is 14. I started very low, under 20. Do you know of any progress on immune therapies to raise the counts? I have been following Cytheris and IL-7 therapy but the trials are taking a very long time. Thanks for your help.

Nelson's answer:

Thanks for this interesting question.

Researchers have discovered that the human body hosts 100 trillion mostly benign bacteria, which help digest food, program the immune system, prevent infection, and even influence mood and behavior.

Everybody hosts at least 10,000 different species of bacteria, contributing up to 5 pounds of body weight. Half of your stool is not leftover food. It is microbial biomass.

Last year, scientists presented evidence that everybody has one of three bacterial profiles characterized by high levels of specific bacterial species.

Microbiome research is in its infancy, but there is already evidence that an imbalance of gut flora may cause gastrointestinal problems such as irritable bowel syndrome and Crohn's disease.

Some 80% of a person's gut flora comes from his or her mother. A newborn exits the womb microbe-free, but it is colonized by the mother's vaginal bacteria as it passes through the birth canal. Other microbes are picked up in the first few years of life.

Diet plays a major role in determining what bacteria people host. However, researchers are still trying to determine what factors could set the microbe population (microbiome) in a good direction versus a bad direction.

Pills, drinks, and yogurts containing probiotic bacteria have become very popular with several TV ads showing daily. A review of probiotics research by scientists at Yale University found that certain strains of bacteria did appear to reduce diarrhea and alleviate irritable bowel syndrome, and another study showed that they could shorten colds. But researchers still aren't sure which bacterial strains are helpful for which conditions, and how they interact with a person's existing microbiome. PCR testing of gut bacteria is a fast evolving field in the present.

The studies that you mentioned that showed that probiotics increase CD4 cells have been done in monkeys infected with simian immunodeficiency virus (SIV) and not in humans with HIV. We need to wait until further data are available from human studies to say for sure if probiotic supplements help HIV+ patients increase their CD4 cells. More information on the studies here: "Effect of HAART on beneficial gut microbes."

I take probiotics when I have diarrhea or after I take antibiotics for any reason. There are several commercially available products out there. Some have more human data than others. I take Culturelle since that was a product used in the latest monkey study that looked at CD4 cells in SIV-infected monkeys supplemented with probiotics.

Interleukin 7 therapy has been shown to increase CD4 cells in HIV-positive patients. However, it is still in early phases of research. A recent study showed that interleukin 7 could not decrease the amount of HIV reservoirs in HIV-positive patients that were treated with it. It is definitely an exciting cytokine that may improve CD4 cells for people who have not responded immunologically to HIV medications. But we will have to wait at least 2 to 3 years to get more access to this option.

Another approach that has been researched lately for patients who do not have increases in CD4 cells over 200 cells per milliliter has been the Sangamo zinc finger nuclease technology that modifies a patient's CD4 cells in the lab so that they are resistant to HIV infection. In early phase 1 studies patients gained a substantial amount of CD4 cells after an infusion of their own CD4 cells which were modified in a lab to have CCR5 receptor mutations. Sangamo is currently studying patients like you to explore the use of their technology as a means to increase CD4 cells in those who have not been able to normalize their CD4 counts after years of HIV treatment. We will keep you abreast of any progress in this area.

I hope this update helped you. Stay tuned for upcoming research data in the field of what we call immunological discordant responders (those who have undetectable viral load for a few years but whose CD4 cells remain under 200 cells/ml).