Cytometric analysis and clinical features in a Moroccan cohort with severe combined immunodeficiency

Article type: Research Article

Authors: El Allam, Aicha^{a; b; *} | El Fakihi, Sara^{a; d} | Tahoune, Hicham^e | Sahmoudi, Karima^{a; f} | Bousserhane, Houria^{a; d} | Bakri, Youssef^{b; g} | El Hafidi, Naima^{c; h} | Seghrouchni, Fouad^{a; d; *}

Affiliations: [a] Laboratory of Cellular Immunology, National Institute of Hygiene, Rabat, Morocco | [b] Laboratory of Biology and Human Pathology, Faculty of Sciences, University Mohammed V, Rabat, Morocco | [c] Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA | [d] Med Biotech Laboratory, Faculty of Medicine and Pharmacy, University Mohammed V, Rabat, Morocco | [e] Department of Biology, Faculty of Sciences, University Ibn Tofail, Kenitra, Morocco | [f] Department of Biology, Faculty of Sciences, University Mohammed V, Rabat, Morocco | [g] Centre of Human Pathology Genomic, Faculty of Medicine and Pharmacy, University Mohammed V, Rabat, Morocco | [h] Immunology, Allergic and Respiratory Diseases Unit, Children’s Hospital of Rabat, Ibn Sina University Hospital Centre, Rabat, Morocco

Correspondence: [*] Corresponding authors: Fouad Seghrouchni, Laboratory of Cellular Immunology, National Institute of Hygiene, Rabat, Morocco. E-mail: [email protected]. Aicha El Allam, Department of Immunobiology, Yale University School of Medicine, 333 Cedar Street, TAC 610, New Haven, CT 06519, USA. E-mail: [email protected].

Abstract: Severe combined immunodeficiency (SCID) is a form of primary immunodeficiency disease (PID). It is characterized by a serious abnormality of the cellular and sometimes humoral system due to a deficiency in development of T cells, B cells and/or NK cells. The early diagnosis of SCID improves the prognosis. Typically, the initial consideration of SCID is made based on low lymphocyte counts. Notwithstanding, the heterogeneity of lymphocyte count presentation makes the diagnosis of SCID a significant challenge. The objective of this cross-sectional retrospective study was to analyze the lymphocyte subpopulation counts along with clinical manifestations within a Moroccan cohort diagnosed as SCID compared to children diagnosed with non-PID diseases. Thirty-five SCID confirmed patients were selected in the period between 2008 and 2018 and compared with non-PID patients. Results of peripheral blood T, B, and NK lymphocyte subpopulation counts were measured by flow cytometry for each SCID subtype. As expected, T cell count was less than 300 cells/μL in most patients with SCID (85.5%). Unexpectedly, significantly higher T cell counts were detected in some patients with a confirmed clinical diagnosis and family history of SCID. 5.7% of our SCID Moroccan cohort had T cell numbers in the range between 300 and 500 cells/μL. 8.7% of our SCID Moroccan cohort had T cell numbers higher than 500 cells/μL. Of the SCID subtypes, the proportion of SCID with B cell deficiencies was highly represented in our cohort. 71.4% of Moroccan SCID patients (25 out of 35 patients) were of T-B-subtype. Furthermore, 40% of the patients (14 out of 35 patients) had a T-B-NK+ profile and 31.4% had a T-B-NK- profile (11 out of 35 patients). The most common clinical manifestations observed in our SCID cohort were pneumonia, failure to thrive, candidiasis, diarrhea, bronchitis and urinary tract infections. Our results not only highlight the relatively frequent presence of atypical SCID in the Moroccan population with unexpectedly high T cell numbers, but also describes the incidence pattern of common SCID subtypes in Morocco. Physicians in Morocco may find this local region-specific difference in SCID important for making improved early diagnosis of this disease.

Keywords: Severe combined immunodeficiency, diagnosis, primary immunodeficiency, lymphocytes subpopulation counts, flow cytometry, Morocco

DOI: 10.3233/HAB-211510

Journal: Human Antibodies, vol. 30, no. 2, pp. 67-77, 2022