[4] Patients with combined immune deficiencies typically exhibit recurrent gastrointestinal and respiratory tract infections, which can be attributed to a wide variety of bacteria.

Other intracellular microbes, such as mycobacteria, can be difficult to control in CID patients, as can opportunistic or normally non-pathogenic infections caused by Pneumocystis jirovecii or Candida.

[1] Treatment for combined immunodeficiencies with defects in antibody production primarily consists of immunoglobulin replacement therapy.

[5] For patients with severe and lethal forms of inborn errors of immunity, hematopoietic stem-cell transplantation is currently the curative treatment of choice.

There has been reported to be a diagnostic delay of a few days to several years between the age at which the disease first manifests and the diagnosis of CID.