Doctors Hospital at Renaissance is putting out another call for plasma as the Rio Grande Valley sees another significant rise in COVID-19 cases. DHR is asking for plasma donations from people who’ve been infected with the coronavirus and recovered. Patients who’ve recovered from COVID-19 develop antibodies against the virus and those antibodies can help other patients fight off the virus. Hospital officials say the post-Thanksgiving increase in COVID-19 cases has reduced their supply of plasma. DHR says it especially needs plasma from people with Type B and Type O blood.