BTK and hyperinsulinemic hypoglycemia, familial, 4: Given the suppressive effects of BTK inhibitors or Btk deficiency on cytokine production and inflammatory responses (24, 94), the clinical trials on COVID-19 are evaluating if acalabrutinib or ibrutinib can lessen the inflammatory responses in the lungs and reduce respiratory failure in patients, while preserving overall immune function (138–143).