Selective IgA deficiency. Immunologic and cytogenetic studies

24 cases of selective IgA deficiency were found among 2,650 children studied in an immuno-Allergy service. The population studied must therefore be considered highly selected. The Amman and Hong criteria were used as a basis for diagnosis (Table 1). Even though they are currently being revised, they are still on some practical value. Statistically, the incidence of selective IgA deficiency in this study is higher (0.905%) than in other publications. Respiratory symptoms were the most important. Only one case presented digestive symptoms (resembling coeliac disease), and no cases with autoimmune disease were found, although the possibility of its occurrence later on cannot be dismissed. A cytogentic analysis was performed in 8 cases and interesting results were found. Five cases showed an increase in heterochromatic material in the paracentric region (1qh+, 2qh+, 16qh+ and Yqh+). These polymorphic variations are present in the general population without any apparent clinical significance, even though their presence in several clinical has been described. However, in this study the frequency seems higher than in the general population. In 2,051 cases studied for other reasons, the frequency of occurrence of polymorphic traits was 3.12%, while in the cases studied by us the incidence amounted to 62.5%, a highly significant proportion. Our data do not try to establish a relationship between the chromosomal alterations and the etiology of the IgA deficiency, even through some relationship may in the future be found to exist.