Epidemiology of combined immunodeficiencies affecting cellular and humoral immunity– a multicentric retrospective cohort study from the Arabian Peninsula

Aims: To understand the characteristics of combined immunodeficiency disorders that affect cellular and humoral immunity (CID) in the Arabian Peninsula. Methods: Retrospective study of 236 patients with CID from the region were enrolled from 2004 to 2022. Results: 236 patients were included with a majority being profound CID. Among patients with a family history of CID, the ages at onset and diagnosis, and the delay in diagnosis were lower compared to those with no family history of CID, but this did not affect time to transplant. HSCT was performed for 51.27% of the patients with median time from diagnosis to HSCT of 6.36 months. On multivariate analysis, patients who underwent early transplant had increased odds of having CD3 count ≤1000 cell/μl, diagnosed by screening or erythroderma. Conclusion: There is a delay in diagnosis and treatment of CID in our region. Establishing newborn screening programs and HSCT units in our region are the urgent need.