SARS-CoV-2-Specific T Cell Responses in Immunocompromised Individuals with Cancer, HIV or Solid Organ Transplants

Abstract

Adaptive immune responses play an important role in the clinical course of SARS-CoV-2 infection. While evaluations of the virus-specific defense often focus on the humoral response, cellular immunity is crucial for the successful control of infection, with the early development of cytotoxic T cells being linked to efficient viral clearance. Vaccination against SARS-CoV-2 induces both CD4+ and CD8+ T cell responses and permits protection from severe COVID-19, including infection with the currently circulating variants of concern. Nevertheless, in immunocompromised individuals, first data imply significantly impaired SARS-CoV-2-specific immune responses after both natural infection and vaccination. Hence, these high-risk groups require particular consideration, not only in routine clinical practice, but also in the development of future vaccination strategies. In order to assist physicians in the guidance of immunocompromised patients, concerning the management of infection or the benefit of (booster) vaccinations, this review aims to provide a concise overview of the current knowledge about SARS-CoV-2-specific cellular immune responses in the vulnerable cohorts of cancer patients, people living with HIV (PLWH), and solid organ transplant recipients (SOT). Recent findings regarding the virus-specific cellular immunity in these differently immunocompromised populations might influence clinical decision-making in the future.

Humoral and cellular immune response in patients of liver cirrhosis and immunocompetent recipient of ChAdOx1nCoV-19 Vaccine (Covishield)

“…Costiniuk et al, in their study on HIV patients, found that anti-RBD and anti-S antibody levels were maintained in 92% patients after 6 months and in 100% patients after 1 month of third dose and suggested timely booster administration in HIV patients for improved immune response [ 23 ]. Studies have shown reduced seroconversion in immunocompromised patients [ 24 ]. Therefore, many European countries recommend booster (third) dose for immunocompromised individuals; even some countries advocate extended (forth dose) or yearly dose in susceptible and vulnerable population with different cut-off for age, citing the waning effect of vaccination over time [ 25 ].…”

T-cell responses to ancestral SARS-CoV-2 and Omicron variant among unvaccinated pregnant and postpartum women living with and without HIV in South Africa

“…have been associated with increased risk of fatal outcomes during acute Covid-19 [24]. However, the CD4 + /CD8 + T-cell ratio appears to remain constant during SARS-CoV-2 infection in PWH compared with HIV-uninfected individuals in whom the ratio is increased [25].…”

“…A total of 24 HIV-uninfected women (n = 12 pregnant, n = 12 postpartum) and 15 WLWH (n = 5 pregnant n = 5 postpartum, n = 5 not pregnant) were recruited with a median age of 30 years (IQR: [22][23][24][25][26][27][28][29][30][31][32][33] and 34 years (IQR: 29-40; p = 0.035), respectively. Most of the participants (56.4%, 22/39) had been infected with the Beta variant (B.…”

Macrophage migration inhibitory factor receptor CD74 expression is associated with expansion and differentiation of effector T cells in COVID-19 patients

“…Both CD4+ and CD8+ T cells are necessary for viral control. Accordingly, cellular or functional T-cell deficiencies are associated with severe COVID-19 disease courses ( 20 ). However, an uncontrolled activity of these cells can lead to inflammation in infected organs and subsequent severe pathologies.…”