[Primary immunologic deficiency by deficiency of HLA class II antigens: nine new Tunisian cases]. / Déficit immunitaire primitif par défaut d'expression des antigènes HLA de classe II: neuf observations tunisiennes.

BACKGROUND: Bare lymphocyte syndrome is a rare inherited primary immunodeficiency. The majority of the patients reported to date are from North Africa. We report nine new Tunisian cases. POPULATION AND METHODS: Over a period of 5 years, we have established the diagnosis of bare lymphocyte syndrome in nine patients who belong to seven different families. Class II HLA antigen expression was studied on resting peripheral mononuclear cells and PHA blasts. RESULTS: The clinical symptoms started at the mean age of 4.5 months (2-10 months) with chronic diarrhea. The evolution was characterized by appearance of other recurrent infections: pneumopathies (seven cases), thrush (seven cases), otitis (five cases) and septicemia (four cases). Allergic manifestations were observed in four cases. Six patients died at the mean age of 30 months from severe denutrition. Class II HLA antigens were not expressed on resting and activated lymphocytes. The absolute count of TCD4+ lymphocytes was decreased in seven patients. Lymphoproliferative response to specific antigens was absent. Four patients had panhypogammaglobulinemia. CONCLUSION: This study confirms the frequency of this disease among the North African population. The severity of the recurrent infection suggests the diagnosis of bare lymphocyte syndrome. This disease is fatal in the absence of bone marrow transplantation.