EPIDEMIOLOGY AND ETHNIC ASPECTS OF B-CELL CHRONIC LYMPHOCYTIC-LEUKEMIA IN ISRAEL

Chronic lymphocytic leukemia (CLL) represents 30% of all leukemias in Caucasians. In East Europe and USA the disease incidence is high while in Asia and Africa CLL is rare. The present study deals with 302 case s of B cell CLL and related disorders; 207 patients originating from E urope and America (Ashkenazi Jews) and 95 descendants from Asia, The M editerranean or Africa (Sephardic Jews). The patients were recruited d uring 1975-1996 in a single center covering the Hashfela region - a So uthern area of Israel with a current population of 430 000 inhabitants . Incidence of the disease, clinical pattern, biological parameters, p rognosis and outcome were investigated and compared in both ethnic gro ups. The results of this study show a high incidence of CLL in Israel. The mean annual age-adjusted incidence 4.3 per 100 000 person-year is among the highest reported values. Our study confirms previous data o n the prevalence of CLL in Ashkenazi compared to Sephardic Jews. The r ise in CLL rate in the reviewed period occurred in both populations, m ainly in the Sephardic group. The relative risk for Ashkenazies compar ed to Sephardics decreased from 6.0 in the 1975-1979 period to 2.4 in 1990-1996. A high rate of CLL was found in new immigrants from the for mer USSR with 26 cases de novo diagnosed and 11 prevalent cases not in cluded in this series among approximately 60 000 new immigrants in the ara over the last 8 years. No differences were found in clinical, lab oratory and immunological parameters at the time of diagnosis in the t wo ethnic groups. The follow-up showed a similar pattern in the diseas e evolution. A preliminary study of immunoglobulin heavy chain rearran gement performed in 14 patients showed no significant differences in J H hybridization in the early stages of the disease, but more aberratio ns in advanced CLL in the Ashkenazi group. Our findings suggest that e thnic origin of the patients itself does not affect the biological and clinical behavior of this disease.