IMMUNOLOGICAL PHENOTYPE ANALYSIS OF PATIENTS WITH FANCONIS-ANEMIA ANDTHEIR FAMILY MEMBERS

In contrast to patients affected with Fanconi's anaemia (FA), who are homozygotes, parental heterozygotes are generally considered normal. I n this preliminary work the main immunological phenotypes of circulati ng mononucleated cells were studied, both in homozygous and heterozygo us subjects. The statistical analysis of results showed that two sets of variables may be distinguished: (a) the first set, including CD20, CD4, CD8 cell markers and CD20/CD3 and CD4/CD8 ratios, that was able t o differentiate between FA patients and the other subject groups; (b) the second set, including CD25, HLA-DR, HLA-DP, HLA-DQ cell markers, t hat was able to differentiate healthy subjects from the other groups. Therefore, in contrast with the literature data, immunological abnorma lities may already be present in parental heterozygotes of FA patients . These subjects displayed a reduced number of cells expressing both s pecific (CD25) and non-specific (HLA) antigens. This defect was more s evere in FA homozygous patients, who showed, in addition, a reduced to tal lymphocyte count, reduced levels of T helper (CD4+) and B lymphocy tes (CD20+), and a reduced CD4+/CD8+ cell ratio. In conclusion, our re sults suggest the presence of a grading of immunological defects in FA patients and family members. Our suggestion needs to be confirmed by functional studies.