EXTENDED FAMILY STUDIES FOR THE IDENTIFICATION OF BONE MARROW (BM) DONORS IN JEWISH AND ARAB PATIENTS.
T Klein, J Stein, E Hershkovitz, R Narinsky, B Kfir, C Or, H Zakai, Y Gat, BZ Garty and I Yaniv, Tissue Typing Lab and Transplant Unit, Rabin Medical Center and Schneider Children's Medical Center of Israel, Petah Tikva, Sackler School of Medicine, Tel Aviv University, Israel.

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The most suitable donor for a patient in need of an allogeneic BMT is an HLA genotypically identical donor which is available for only a small portion of the patients. When an HLA identical core family member is not found, it is possible to perform an extended family search. During the last 10 years (1990-1999), 356 patients and 3,015 of their family members were tissue typed in order to find a matched donor; 239 (67%) were Jewish and 117 (33%) were Arab. An HLA identical donor was identified for 168 (47%) patients of which 49 (29%) had more than one potential donor. Of the Jewish patients, 95 (39.7%) had a matched donor while for the Arab patients, genotypically identical donor was identified for 73 (62.3%). In 38 families where a matched sibling was not identified, an extended family search (grandmother/father, cousins, uncles, etc.) was performed. Among 5 Jewish families, only one HLA genotypically identical donor was found while 21 out of 33 (63.6%) Arab patients had an HLA genotypically identical donor in the extended family. We conclude that extended family search for potential identical HLA donors is worthwhile especially when performed in distinct ethnic populations such as Israeli-Arab where consanguinity often prevails thus offering substantial chance of finding donors other than core family members.