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

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.

Age-stratified pediatric reference values of lymphocytes in the Moroccan population.

The number of circulating lymphocytes is altered in a number of diseases including either increase (lymphocytosis) or decrease (lymphocytopenia). Therefore, the assessment of total blood lymphocyte numbers and the relative distribution of lymphocyte subsets is a critical front-line tool in the clinical diagnosis of a number of diseases, including pediatric diseases and disorders. However, the interpretation of this data requires comparison of patient's results to reliable reference values. Blood lymphocyte subpopulation numbers are also subject to genetic polymorphisms, immunogenic and environmental factors and vary greatly between populations. While the best practice reference values should be established within local representative populations of healthy subjects, to date, Caucasian reference values are used in Morocco due to the absence of indigenous reference values. Potential differences in blood lymphocyte subpopulation reference values between Caucasian versus Moroccan populations can adversely affect the diagnosis of pediatric and childhood diseases and disorders such as primary immunodeficiency (PID) in Morocco. OBJECTIVE: The aim of this study was to establish the age-stratified normal reference values of blood lymphocyte subsets for the pediatric Moroccan population. METHODS: We measured the concentration of lymphocyte subpopulations by flow cytometry from 83 Moroccan healthy subjects stratified into 5 age groups of 0-1, 1-2, 2-6, 6-12 and > 12-18 (adult). RESULTS: The absolute and relative amounts of the main lymphocyte subsets of T-cells, B cells and Natural Killer (NK) cells were measured and compared to previously described reference values from Cameroonian, Turkish, American and Dutch populations. Additionally, we also observed an age-related decline in the absolute population sizes of lymphocyte subsets within our study group. Relative proportions of CD3+CD4+ helper T lymphocytes decreased with increasing age and by 12 years-adult age, both proportions of CD3+CD4+ helper T lymphocytes and CD3+CD8+ cytotoxic T lymphocytes, as well as CD3-CD19+ B lymphocytes were also decreased. Finally, we compared the median values and range of our Moroccan study group with that of published results from Cameroon, Turkey, USA and Netherlands and observed significant differences in median and mean values of absolute number and relative proportions of lymphocyte subsets especially at 0-1 years and 1-2 years age groups. Above age 12 years, the Moroccan values were lower. For NK cells, the Moroccan values are also lower. CONCLUSIONS: The results of this study have a significant impact in improving the threshold values of the references intervals routinely used in the diagnosis of paediatric diseases such as PIDs or mother-to-child transmitted HIV within the Moroccan population.

Moroccan lymphocyte subsets reference ranges: age, gender, ethnicity, and socio-economic factors dependent differences.

Lymphocyte subsets reference ranges are helpful for a precise diagnosis and therapy of various diseases. We attempted in the current study to establish Moroccan lymphocyte reference range and reveal age, gender, ethnicity, income, and instructional levels dependent differences. Lymphocyte subsets percentage and absolute count were determined by 4-color flow cytometry in a population study of 145 adults Moroccan healthy volunteers. Analysis showed significant age-dependent changes. Age was associated with a decrease of naïve CD4+ and CD8+ T cells and an increase of memory CD4+ or CD8+ T cells. Activated CD4+ CD38+ and CD8+ CD38+ T cells, Treg as well as NK cell showed age-dependent alterations. In contrast, B cells remained unchanged. A higher percentage of CD3+ and CD4+ T cells was observed in females while CD8+, B and NK cells count were higher in men. Ethnicity, instructional levels, and personal income seem to not influence lymphocyte subsets reference values. This study provides reference ranges for lymphocyte subsets of healthy Moroccan adults. These results can be used for other North African (Maghrebian) countries considering their geographic, ethnic, economic, and cultural similarities.

Immune activation and regulatory T cells in Mycobacterium tuberculosis infected lymph nodes.

BACKGROUND: Lymph node tuberculosis (LNTB) is the most frequent extrapulmonary form of tuberculosis (TB). Studies of human tuberculosis at sites of disease are limited. LNTB provides a unique opportunity to compare local in situ and peripheral blood immune response in active Mycobacterium tuberculosis (Mtb) disease. The present study analysed T regulatory cells (Treg) frequency and activation along with CD4+ T cell function in lymph nodes from LNTB patients. RESULTS: Lymph node mononuclear cells (LNMC) were compared to autologous peripheral blood mononuclear cells (PBMC). LNMC were enriched for CD4+ T cells with a late differentiated effector memory phenotype. No differences were noted in the frequency and mutifunctional profile of memory CD4+ T cells specific for Mtb. The proportion of activated CD4+ and Tregs in LNMC was increased compared to PBMC. The correlation between Tregs and activated CD4+ T cells was stronger in LNMC than PBMC. Tregs in LNMC showed a strong positive correlation with Th1 cytokine production (IL2, IFNγ and TNFα) as well as MIP-1α after Mtb antigen stimulation. A subset of Tregs in LNMC co-expressed HLA-DR and CD38, markers of activation. CONCLUSION: Further research will determine the functional relationship between Treg and activated CD4+ T cells at lymph node sites of Mtb infection.