HIV and Lower Risk of Multiple Sclerosis: There is a Connection

Recently, researchers had discovered that HIV infection might decrease the risk of developing multiple sclerosis (MS).

This finding had opened the debate about the possible explanations of why.

MS is generally classified as a CD4+ Th1/Th17-mediated inflammatory disease, but recent studies have shown an important role of both CD8+ and CD19+ B cells in the pathogenesis of the disease.

And, the way HIV works is that it can infect CD4+ T cells, macrophages, and microglial cells, inducing a dysfunction of the acquired immune response.

As such, Tatiana Koudriavtseva, MD, Regina Elena National Cancer Institute, Rome, Italy, and colleagues sought to analyze the number of circulating CD3+, CD4+, CD8+, and CD19+ lymphocytes in a cohort of RRMS patients in a group of antiretroviral (ART)-treated HIV patients and compare them with a healthy control group.

Using flow cytometry, the team assessed the number of circulating CD3+, CD4+, CD8+, and CD19+ lymphocytes of 46 RRMS patients — 23 were in relapse and 23 were in remission, and 40 ART-treated HIV patients.

The administered 18 MS patients with immunomodulatory drugs like interferon-beta and copolymer.

Study results indicated four distinct points:

1. Circulating CD3+ cells were found to be lower in MS patients as compared with the controls and HIV patients.

2. Both HIV groups (relapse and remission and ART-treated patients) showed higher circulating CD3+ lymphocytes than both RRMS patients in relapse and in remission.

3. Circulating CD8+ cells were increased in both ART-treated HIV groups as compared to RRMS patients both in relapse and in remission, and to healthy controls.

4. The CD4/CD8 ratio was reduced in both ART-treated HIV groups as compared to healthy subjects and to RRMS patients, both in relapse and in remission.

Experts attribute the lack of significant reduction in the number of CD4+ lymphocytes within the HIV group to the ongoing ART. “Interestingly, we found a reduction of circulating CD3+ cells in MS patients as compared both to controls and to HIV patients, suggesting their accumulation in the central nervous system as MS target organ,” noted the authors.