Immune Memory is Less Durable After Severe COVID-19 Infection

Infection-fighting B cells retain better memory of the coronavirus spike protein in University Hospital patients who recover from less-severe cases of COVID-19 than in those recovering from severe COVID-19, suggests a new study published in the journal PLOS ONE.

The study focused on memory B cells that react against the SARS-CoV-2 spike protein. Blood samples were analyzed one month after symptom onset and five months post-onset. After one month, a significant proportion of spike-specific B cells were active.

‘A more dysfunctional B cell response is seen in severe COVID-19 cases.’

However, samples from eight individuals who recovered from less-severe disease showed increased expression of markers associated with durable B cell memory as compared to individuals who recovered from severe disease.The markers include T-bet and FcRL5.

T-bet-positive, spike-specific B cells nearly disappeared from the blood samples five months post-symptom onset.

Non-severe cases were defined as not requiring supplemental oxygen or invasive ventilation, while severe cases needed invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO).

"The definition of severe disease was made based on the need for mechanical ventilation or ECMO because this distinguishes the most critical patients, who are the most likely to develop impaired immune responses," said study senior author Thomas Patterson, MD, professor and chief of infectious diseases at UT Health San Antonio who leads COVID-19 care at clinical partner University Health.

Study participants were enrolled in the Adaptive COVID-19 Treatment Trial (ACTT)-1 or ACTT-2 clinical trials. Samples were from University Health patients co-enrolled in the UT Health San Antonio COVID-19 Repository.

The increased percentage of B cells associated with long-lived immunity in non-severe COVID-19 patients may have consequences for long-term immunity against SARS-CoV-2 re-infection or severity of the resulting disease.



Source: Medindia