Kinetics of T cell response, inflammatory profile and induction of smallpox-specific T cells in monkeypox infection

Preprints with The Lancet*describes changes in immune T cell profile over time after infection with monkeypox virus.


A history of smallpox vaccination confers 85% protective immunity against monkeypox, although this is limited to people aged 40 or older. CD8 T cells appear to play a major role in the cellular immune response to monkeypox virus. All convalescent cases develop specific responses to the virus (IgM, IgG, B and T cells).

During the first 3 days post-infection, CD4 T cells were markedly reduced while CD8 T cells increased in proportion. CD4 and CD8 T cells exhibited predominantly the effector memory cell phenotype, with a reduced frequency of naïve cells, indicating active engagement with the virus. Over time, the relative proportions normalized.

These changes occurred independently of HIV status, indicating preservation of the immune response. These responses occurred mostly in those with more or larger lesions and systemic symptoms.

What are the conclusions?

The virus clade currently circulating is very similar to that from West Africa and appears to evoke an early immune-inflammatory response, indicating that protective innate immune responses are at work. This could explain the preponderance of mild infections.

Disruption of adaptive cellular immunity by HIV infection did not appear to impede the rapid and effective response to monkeypox, although all patients in this study had well-controlled HIV. These results support other research showing that HIV does not affect the presentation or severity of monkeypox. Additionally, she suggests that monkeypox vaccines may be equally effective in PLHIV.

Further work should be devoted to patients with advanced HIV infection, whose cellular immune capacity is presumably lower.

*Important Note

The Lancet Preprints publishes preliminary scientific reports which are not peer-reviewed and therefore should not be considered conclusive, guide clinical practice/health behavior or be treated as established information .

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