Four aged siblings with B cell chronic lymphocytic leukemia

All four aged siblings (>80 years) of one family presented with B cell chronic lymphocytic leukemia (B-CLL). In an attempt to find common characteristics in the four patients, we performed detailed immunological marker analysis, Southern blot analysis of immunoglobulin (Ig) genes, and cytogenetic studies, In three patients clonality of the B-cells could be proven by single Ig light chain expression, hut in the fourth patient no Ig light chain expression was detected and clonality of the B cells could only be demonstrated by Southern blot analysis of the Ig genes. interestingly, in two patients, the Ig gene rearrangement patterns were compatible with the presence of two independent B cell clones, whereas in the two other siblings a monoclonal rearrangement pattern was found, All four patients showed clonal chromosome aberrations, which were different in each patient. In the two patients with biclonal Ig gene rearrangement patterns, two unrelated clones could also be demonstrated by the cytogenetic studies. These combined Ig gene and cytogenetic data indicate the presence of two different B-CLL in two of the four patients. Remarkably, the B-CLL cells of the hive oldest patients expressed the CD8 antigen, which is rarely observed, Our finding of six different B-CLL in the four living siblings indicates that the members of this family are highly susceptible to the development of B-CLL. However we could not identify a common factor to explain this susceptibility further. In contrast to the literature, the occurrence of two B CLL in one patient and the expression of CD8 were not associated with clinically aggressive disease in this family.