PROGNOSTIC-SIGNIFICANCE OF PEANUT AGGLUTININ BINDING IN CHILDHOOD ACUTE LYMPHOBLASTIC-LEUKEMIA

We previously reported the favorable prognosis associated with positiv e peanut agglutinin (PNA) binding in childhood T cell acute lymphoblas tic leukemia (ALL), and hypothesized that this may be related to gluco corticoid sensitivity (Veerman et al. Cancer Res 1985, 45: 1890). The purposes of this prospective study involving 202 children with newly d iagnosed ALL were to determine the relationship between PNA binding an d (1) immunophenotype; (2) in vitro resistance to prednisolone (PRD) a nd dexamethasone and other drugs; (3) clinical response to a systemic PRD monotherapy (plus one intrathecal injection with methotrexate); an d (4) multidrug chemotherapy. PNA positivity was more frequent in T ce ll ALL (65% of 43 cases) than in pro-B (0% of seven cases), common (17 % of 106 cases) and pre-B (16% of 45 cases) ALL (P < 0.007). PNA bindi ng was not associated with in vitro resistance to PHD or dexamethasone . However, in 38 evaluable T cell ALL patients, nine of 13 PNA-negativ e cases were clinically poor responders to PRD, while all 25 PNA-posit ive cases were good responders to PRD clinically (P < 0.0001). The fou r clinically poor PHD responders with B cell precursor (BCP)-ALL were also PNA negative. Within T sell ALL, PNA-positive patients had a 3.4- fold (95% CI, 1.1-10.4, P = 0.03) lower relative risk of any event, th an PNA-negative patients. Within BCP-ALL, PNA binding was not of progn ostic significance. In conclusion, PNA positivity, especially frequent in T cell ALL, is a marker for a subgroup of childhood ALL patients w ho are very likely to respond well to systemic PRD 'monotherapy'. In a ddition, PNA positivity is a favorable. prognostic factor in T cell AL L.