Background: Familial chronic lymphocytic leukemia (CLL) has the most frequent familial aggregation among hematological malignancies. Familial CLL families have been studied to identify susceptibility genes and other factors that contribute in the etiology of CLL. To date no study has been conducted to evaluate and compare patterns of cell surface antigen expression in familial CLL and sporadic CLL.
Methods: The pattern of cell surface antigen expression was studied in familial and sporadic CLL to determine if unique identifiers of familial CLL could be detected. Survival in familial CLL verses sporadic CLL was compared and the association between prognosis and CD38 expression studied.
Results: Familial and sporadic CLL demonstrated the same characteristic immunophenotype (positive for surface immunoglobulin, CD5, CD19, and CD23 with dim CD20, and CD22). CD2 and CD13 expression, however, were more frequent (30% of cases) in familial CLL (P = 0.0003 for CD2, P = 0.006 for CD13) than in sporadic CLL (2-6%). There was no significant difference in survival in the two groups studied. Although the incidence of CD38 expression was similar in familial and sporadic CLL (47% and 44% respectively) the association with prognosis differed. There was a trend to decreased survival in CD38 positive sporadic (P = 0.06) but not familial CLL patients.
Conclusions: We conclude that detection of CD2 or CD13 expression in CLL suggests familial CLL and examination of family history for additional affected members is warranted. Furthermore, CD38 expression does not carry the negative prognosis observed in sporadic CLL.