Antiretroviral therapy has transformed HIV into a manageable condition. However, some patients remain HIV immunological non-responders who cannot adequately restore their CD4+ T-cell counts. These individuals face increased risks of morbidity and mortality because their immune systems stay compromised. Scientists recently analyzed multi-omics data from the 2000HIV study to understand this phenomenon. Their findings highlight the critical role of the Src kinase-associated phosphoprotein 1, or SKAP1, in immune reconstitution.

Biological Pathways in HIV Immunological Non-Responders

The study compared plasma protein levels between responders and non-responders. Significantly, the research team found that HIV immunological non-responders have much lower SKAP1 concentrations. These plasma levels directly reflect the intracellular levels within CD4+ T-cells. Because SKAP1 facilitates T-cell proliferation and migration, its depletion poses a significant hurdle. Consequently, the body cannot effectively rebuild its immune defense.

Moreover, DNA methylation analysis provided a biological reason for this protein deficiency. The team discovered significant hypermethylation at the SKAP1 promoter region. This epigenetic change essentially silences the gene, leading to reduced protein production. Furthermore, three specific single-nucleotide polymorphisms close to the gene appeared to associate with poor immune responses. Preliminary data also suggest that persistent infections like CMV might further suppress SKAP1 expression.

Future Directions for Immune Restoration

These insights offer a potential roadmap for new treatment strategies. Addressing the hypermethylation of the SKAP1 promoter might help revive T-cell activity. Additionally, monitoring SKAP1 levels could serve as a biomarker for clinical risk. Clinicians should remain aware of these biological barriers when managing patients with persistently low CD4 counts despite viral control.

Frequently Asked Questions

What defines HIV immunological non-responders?

These are individuals living with HIV who achieve viral suppression through antiretroviral therapy but fail to restore their CD4+ T-cell counts to healthy levels, typically remaining below 350 or 500 cells/mm³.

How does SKAP1 influence immune recovery in HIV?

SKAP1 is an adaptor protein essential for T-cell proliferation and migration. Low levels of this protein, often caused by DNA hypermethylation, hinder the body's ability to regenerate the CD4+ T-cell pool.

Disclaimer: This content is for informational and educational purposes only. It does not constitute professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified healthcare provider with any questions you may have regarding a medical condition. Refer to the latest local and national guidelines for clinical practice.

References

1. Vos WA et al. HIV immunological non-responders show low SKAP1 concentration and DNA hypermethylation in the SKAP1 promotor region: Low Skap1 in HIV Immunological Non-Responders. AIDS. 2026 Apr 21. doi: 10.1097/QAD.0000000000004529. PMID: 42013451.


2. Vos WA et al. HIV immunological non-responders are characterized by extensive immunosenescence and impaired lymphocyte cytokine production capacity. Frontiers in Immunology. 2024 May 8;15:1350065.


3. Huang J et al. Multi-functional adaptor SKAP1: regulator of integrin activation, the stop-signal, and the proliferation of T cells. Frontiers in Immunology. 2023 May 31;14:1192838.