P.Patients with hematologic cancers such as leukemia who are hospitalized with COVID-19 are more likely to die than those with solid cancers who contract the infection and go to hospital. This is evident from an analysis published as a preprint for In retrospect on February 2nd. The researchers suggest that an impaired immune response in blood cancer patients with acute COVID-19 could lead to these poor results, as they found that CD8 + T cell depletion was associated with the highest mortality among all participants.
“When you think about it, it makes sense. By definition, patients with leukemia have cancer of the immune system, ”says Mikkael Sekeres, head of hematology at the University of Miami’s Sylvester Cancer Center, who was not involved in the study. Corrupt bone marrow produces abnormal white blood cells, making people with leukemia primarily more susceptible to infection, adds Sekeres, who is a member of a research group at the American Society of Hematology that collects ongoing data on clinical outcomes from blood cancer patients with COVID -19.
Since the pandemic began, several studies have shown that cancer patients with COVID-19 have higher death rates than those without cancer, especially if the cancer is in the blood. The reason is unclear. “Perhaps inadequate immune responses are part of the problem,” says Santosha Vardhana, an oncologist at Memorial Sloan Kettering Cancer Center and the study author.
Even if [blood cancer patients] After clearing the virus, they still seem to have a lingering effect from COVID, making it look more like a chronic infection.
– Sheeba Irshad, King’s College London
Vardhana and colleagues wanted to find out which immune profiles correlate with a higher risk of death in cancer patients with COVID-19 and whether blood cancer patients are more likely than others to have the riskiest of these profiles. They compared the death rates and immune profiles of blood and cancer patients with COVID-19 at Sloan Kettering in New York and the University of Pennsylvania in Philadelphia.
They saw increased death rates in hospitalized patients with blood cancer and COVID-19 compared to patients with other cancers, as in previous studies. For example, nearly half of 45 blood cancer patients with COVID-19 in Sloan Kettering died in hospital, compared with 20 percent of 39 people with solid cancers.
In a group of COVID-19 patients in Penn, more than half of blood cancer (12 out of 22) died within 30 days of leaving the hospital. This was true for a third (26 out of 78) of patients with solid cancers.
The immune profiles of these two groups could explain the difference, says Vardhana. Compared to COVID-19 patients with solid cancers, patients with blood cancer had elevated markers of inflammation, suggesting an increased immune response to the virus.
“Even if [blood cancer patients] After clearing the virus, they still seem to have persistent effects from COVID, making it look more like a chronic infection, ”says Sheeba Irshad, an oncologist at King’s College London who has also studied cancer patients’ immune responses to COVID . 19 was not involved in this study. According to Irshad, solid cancer patients with COVID-19 generally show an immune response like people without cancer, while blood cancer patients have different immune profiles.
A detailed analysis of the lymphocytes from 45 COVID-19 patients performed at Penn supports Irshad’s claim. Just like those without cancer, most solid cancer patients had a balanced complement of B cells, CD4 + T cells, and CD8 + T cells, all of which are critical to adaptive immunity to a virus. In contrast, those with blood cancer showed lower production of B cells and CD4 + T immune cells, indicating impaired immunity.
At Sloan Kettering, blood cancer patients with few B cells often died in the hospital. Solid cancer patients, on the other hand, found it easier to maintain their B cell counts and usually lived as long as they had enough CD8 + T cells. Patients with significant CD8 + T cell depletion across all cancers died in hospital 71 percent of the time, even when their B cell responses were adequate.
Vardhana notes that some chemotherapies suppress T cells, making it an open question as to whether COVID-19 itself or chemotherapy of a cancer patient contributes more to T-cell depletion. He hopes to address this question in future research.
This study arrives as COVID-19 vaccination programs roll out in the US, prompting the American Association for Cancer Research’s COVID-19 and Cancer Task Force to give priority access to vaccines to cancer patients as cancer is a risk factor for development is severe COVID-19. While this is in line with the recommendations of the U.S. Centers for Disease Control and Prevention, there is little direct evidence of the vaccine-cancer interaction, as many people with cancer have been excluded from vaccine trials.
However, Vardhana argues that vaccination could be helpful for many cancer patients, as both vaccines currently approved in the US produce a robust CD8 + T cell response.
“Given that we have some data to suggest that a T cell response is important and helpful, it is reasonable to obtain it [the vaccine]”Says Vardhana. Irshad is more cautious, arguing that more evidence is needed about the specific benefits of vaccines for cancer patients. Her recommendation is that everyone who cares for someone with cancer – family members and healthcare workers – be vaccinated with it.” there is some protection for this person.
E. Bange et al., “CD8 T cells compensate for impaired humoral immunity in COVID-19 patients with hematologic cancer”. In retrospect, doi: 10.21203 / rs.3.rs-162289 / v1, 2021.