Report of the Tunisian Registry of Primary Immunodeficiencies: 25-Years of Experience (1988-2012).

PURPOSE: Primary immunodeficiencies (PIDs) are a large group of diseases characterized by susceptibility to not only recurrent infections but also autoimmune diseases and malignancies. The aim of this study was to describe and analyze the distribution, clinical features and eventual outcome of PID among Tunisian patients. METHODS: We reviewed the record of 710 patients diagnosed with Primary Immunodeficiency Diseases (PIDs) from the registry of the Tunisian Referral Centre for PIDs over a 25-year period. RESULTS: The male-to-female ratio was 1.4. The median age at the onset of symptoms was 6 months and at the time of diagnosis 2 years. The estimated prevalence was 4.3 per 100,000 populations. The consanguinity rate was found in 58.2 % of families. According to the International Union of Immunological Societies classification, spectrums of PIDs were as follows: combined T-cell and B-cell immunodeficiency disorders account for the most common category (28.6 %), followed by congenital defects of phagocyte (25.4 %), other well-defined immunodeficiency syndromes (22.7 %), predominant antibody deficiency diseases (17.7 %), diseases of immune dysregulation (4.8 %), defect of innate immunity (0.4 %) and complement deficiencies (0.4 %). Recurrent infections, particularly lower airway infections (62.3 %), presented the most common manifestation of PID patients. The overall mortality rate was 34.5 %, mainly observed with combined immunodeficiencies. CONCLUSION: The distribution of PIDs was different from that reported in Western countries, with a particularly high proportion of Combined Immunodeficiencies and phagocyte defects in number and/or function. More is needed to improve PID diagnosis and treatment in our country.

δ0-Thalassemia in cis of ßKnossos globin gene: first homozygous description in thalassemia intermedia Libyans and first combination with codon 39 (C→T) in thalassemia intermedia Tunisian patients.

BACKGROUND: ß-Thalassemia is the most common disease among hemoglobinopathies in North African and Arab populations. In the present study we report the first description of the ß-Knossos codon27 (G→T) (ßKnossos) allele in cis with the δ059 (-A) mutation in thalassemia intermedia patients in Tunisia and Libya. METHODS: This identification was carried out by sequencing analysis of the whole coding regions of the δ- and ß-globin genes. RESULTS: We noted that heterozygous inheritance of the ßKnossos mutation results in a mild ß-thalassemia phenotype with a low level of HbA2 while homozygous leads to intermediate ß-thalassemia with an atypical high performance liquid chromatogram showing a complete absence of HbA2 and HbF. Compound heterozygosity of the ßKnossos with ß0 codon39 (C→T) is identified in a Tunisian proband for the first time and gives rise to a mild phenotype. In both families, the δ0 codon59 (-A) and the ßKnossos alleles were found to be associated with a single Mediterranean ß-haplotype I similar to that observed in previous reports from Algeria, Egypt, Cyprus, and Turkey. CONCLUSIONS: The chromosome supporting the ßKnossos and the δ0 codon59 (-A) alleles seems to be of a single Mediterranean origin. Premarital screening studies in families in which only one of the parents has typical aspects of ß-thalassemia trait and the other has a normal HbA2 level associated with abnormal red cell indices becomes a necessity to avoid missing thalassemia carriers.