Kaposi's sarcoma: the most common tumor after renal transplantation in Saudi Arabia.

Between September 1975 and November 1986, 263 renal transplant recipients at the King Faisal Specialist Hospital and Research Center were followed; 82 procedures were done by the authors using live related donors. Among the 263 patients, 14 cases of Kaposi's sarcoma were identified, an incidence of 5.3 percent compared with an incidence of 0.4 percent in renal transplant recipients from Western countries. In addition, two more patients had other types of tumors. Thus, Kaposi's sarcoma represents 87.5 percent of tumors in the King Faisal Hospital renal transplant population, in contrast to 3.7 percent in the Cincinnati Transplant Tumor Registry. The mean period between transplantation and diagnosis of Kaposi's sarcoma was 12.5 months (range, one to 37 months). Eleven patients were Saudis and three were other Arab nationals. Seven of the 11 Saudi patients were from the southwestern region of the country. Cytomegalovirus titers were not elevated in six of 10 patients. Results of tests for human immunodeficiency virus were negative in seven of eight patients. HLA-A2 antigen frequency was significantly increased in the King Faisal Hospital renal transplant patients with Kaposi's sarcoma as compared with a control population (83.3 percent versus 43.6 percent, p value = 0.006 [P = 0.06 with Bonferroni adjustment]), and increased, though nonsignificantly, compared with the live related kidney transplant recipients without Kaposi's sarcoma (83.3 percent versus 49.4 percent, p value = 0.058 [P = 0.58 with Bonferroni adjustment]), suggesting a genetic predisposition to Kaposi's sarcoma in these patients.