HLA Polymorphism in Algerian Children With Lymphomas.

BACKGROUND: Non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) are the 2 types of lymphoma that represent the third most common childhood malignancy. Multiple etiological factors are involved in lymphoma pathogenesis, including viral infection, immune deficiencies, environmental agents, and genetic factors. Strong arguments supporting a genetic linkage between the susceptibility to lymphomas and human leukocyte antigens (HLA) are reported and give an idea about susceptibility or protection from the disease. METHODS: Seventy-one cases were included in this study: 36 cases of non-Hodgkin lymphoma and 35 patients with Hodgkin lymphoma. Their ages ranged from 4 to 18 years. The control group consisted of 70 unrelated healthy individuals, with a mean age of 5 to 17 years. The genotype of HLA-A, HLA-B, HLA-DR, and HLA-DQ alleles was typed by means of PCR sequence-specific priming. RESULTS: HLA-B*18, HLA-DRB1*03, *07, and HLA-DQB1*02 were significantly increased in patients with lymphomas when compared with controls, whereas HLA-DRB1*13 and DQB1*03 were significantly decreased when compared with controls. CONCLUSIONS: These results indicate that HLA-B*18, DRB1*03, *07, and DQB1*02 may contribute to lymphoma susceptibility, whereas HLA-DRB1*13 and DQB1*03 may confer protection to lymphoma in the Algerian population.

Clinical, immunological and genetic features in eleven Algerian patients with major histocompatibility complex class II expression deficiency.

Presenting processed antigens to CD4+ lymphocytes during the immune response involves major histocompatibility complex class II molecules. MHC class II genes transcription is regulated by four transcription factors: CIITA, RFXANK, RFX5 and RFXAP. Defects in these factors result in major histocompatibility complex class II expression deficiency, a primary combined immunodeficiency frequent in North Africa. Autosomal recessive mutations in the RFXANK gene have been reported as being the principal defect found in North African patients with this disorder. In this paper, we describe clinical, immunological and genetic features of 11 unrelated Algerian patients whose monocytes display a total absence of MHC class II molecules. They shared mainly the same clinical picture which included protracted diarrhoea and respiratory tract recurrent infections. Genetic analysis revealed that 9 of the 11 patients had the same RFXANK founder mutation, a 26 bp deletion (named I5E6-25_I5E6+1, also known as 752delG26). Immunological and genetic findings in our series may facilitate genetic counselling implementation for Algerian consanguineous families. Further studies need to be conducted to determine 752delG26 heterozygous mutation frequency in Algerian population.