We tested anti-polio antibodies titer and delayed hypersensitivity (DHS) to tetanic and diphteric antigens (Multitest-Merieux) in 80 children (42 M, 38 F), aged between 22 and 170 months (median: 103 months), off-therapy for onco-haematologic diseases, to evaluate persistence of immunologic memory after chemotherapy. The immunologic control was performed between 1 month and 55 months (median: 32 months) after stop-therapy. Moreover, we tested immunologic reactivity of those patients who appeared non immune, therefore ulteriorly vaccinated against poliomyelitis, tetanus and diptheria.

46 patients had been treated for ALL (26 cases medium risk, 20 high risk); 5 children had AML, 9 NHL, 4 HL, 4 Histiocithosis, 3 RMS, 3 NB, 2 Wilms' Tumor, 4 other neoplastic diseases; 8 of these patients underwent BMT (3 allogenic BMT, 5 autologous BMT). All patients had been previously protected according to national obligatory vaccination plans.

After the end of therapy 71 children (89%) resulted non immune: 49 subjects(61%) without anti-polio antibodies, and 60 children (75%) Multitest-negative. Both tests appeared negative in 38 children.

The 8 BMT-treated children, the 5 AML patients and the 20 high-risk ALL subjects appeared non immune. Only 3 of 49 patients not immune to poliomyelitis presented hypogammaglobulinemia; only 1 case had IgG lack.

49 of 71 non immune patients underwent another vaccination: 25 of these children (59.5%) had a good response after this first dose; the other 24 patients needed a complete vaccination plan.

Finally, a remarkable percentage of the onco-haematologic patients,(particularly those who underwent aggressive treatment), appears non immune after the end of chemotherapy, 50% of these patients need a complete vaccination plan.