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:
- Circulating CD3+ cells were found to be lower in MS patients as compared with the controls and HIV patients.
- Both HIV groups (relapse and remission and ART-treated patients) showed higher circulating CD3+ lymphocytes than both RRMS patients in relapse and in remission.
- 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.
- 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.