Low IgG or IgA: a further indicator of poor prognosis in childhood acute lymphoblastic leukaemia

Acute lymphoblastic leukemia. A comprehensive review with emphasis on biology and therapy

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children. It is now curable in 60-70% of children. Most of the current understanding of the biology and treatment of ALL originates from studies of children. In adults, although much progress has been achieved, ALL is curable in only 20-35% of patients.

METHODS

A review of the biology and treatment of ALL from the English literature was performed.

RESULTS

Immunophenotypic and cytogenetic analyses of ALL have contributed to a more rational classification of ALL. These analyses have identified subgroups with poor prognosis or with different therapeutic requirements. Overall, 60-70% of adults with ALL have poor prognostic features, including older age, a high leukocyte count, non-T-cell immunophenotype, Ph-positive genotype, and longer time to achieve a complete remission. These patients have a cure rate of 20-25%, whereas those without these risk factors, have a 60-70% probability of survival. The use of more intensive induction regimens with growth factor support may improve survival rates. Also, intensive consolidation-intensification may improve survival rates. Most patients benefit from maintenance therapy, but the dose schedule must be optimized. Central nervous system (CNS) prophylaxis is beneficial, particularly for patients with a high risk for CNS relapse and when introduced early during induction of remission. Patients with high risk characteristics may benefit from allogeneic bone marrow transplantation (BMT) during first remission, and all other patients may benefit from it during first or subsequent relapse. Autologous BMT may be a valuable option for poor compliant patients.

CONCLUSIONS

Although the prognosis of patients with ALL has improved markedly during the past decades, newer strategies, including more dose-intensive therapy, the search for new drugs, and more target-specific therapy, are needed to improve the current cure rates.

Immunoglobulin concentrations in untreated lymphoblastic leukemia

Early studies indicated that low immunoglobulin (Ig) concentrations at diagnosis predict a worse outlook for children with acute lymphoblastic leukemia (ALL). We re-examined this suggestion in the light of immunophenotypic disease subtyping and more modern therapy. The concentrations of Ig, IgA, and IgM at diagnosis of ALL in 199 children were reviewed. One hundred forty-one (71%) had normal values and 58 (29%) had at least one abnormal value. No obvious pattern of abnormality relating to disease immunophenotype emerged. Disease-free survival (DFS) was not significantly different when simply comparing children with normal and abnormal values. Those with a white blood cell count lower than 20 x 10(9)/L (n = 106) included 22 with at least one low Ig whose 5-year DFS was inferior to the "normal" group (56% vs 83%; P < 0.005). The 140 children with CD10 + B precursor ALL included 31 with one or more low Ig concentrations who also showed an inferior 5-year DFS to the remainder (55% vs 77%; P < 0.02). Minor abnormalities in Ig concentrations are seen in approximately one third of children with ALL regardless of immunologic subtype. Low values may relate to poor outcome in patients with the disease at otherwise good risk.

Immunoglobulin levels and lymphocyte response to mitogenic stimulation in children with malignant disease during treatment and follow-up

Intensification of chemotherapeutic regimens has improved survival in childhood malignant disease. To characterize the impact of this intensified therapy on some aspects of the immune system, we have, in an unselected material of 220 children with malignant disease, investigated serum immunoglobulin levels and lymphocyte response at diagnosis and then subsequently during and up to 4 years after cessation of therapy. In leukemia and Hodgkin's disease, all immunoglobulin isotypes decreased during therapy. A profound depression of immunoglobulin M levels, lasting well after completion of therapy, was seen in all tumor types. The mitogenic response was attenuated in patients with leukemia at diagnosis but was rapidly restored after institution of therapy. Patients with solid tumors, particularly Hodgkin's disease, had a reduced mitogenic response during therapy. Thus these patients exhibit multiple immunological disturbances. The basis of the pronounced immunoglobulin M deficiency remains unclear.

Acute lymphoblastic leukemia in children: current status, controversies, and future perspective

Disease-free survival (DFS) in childhood ALL is 60%, and survival in good, average, and poor prognostic groups defined by initial WBC and age is 90, 60, and 45%, respectively. Additional immunological, morphological, biochemical, cytokinetic, and cytogenetic factors have been identified, illustrating the heterogeneity of ALL and its derivation from malignant clones at various stages of differentiation and with varying rates of proliferation. Of biologic importance, these factors may refine further the characteristic features of clinically-determined prognostic groups. Multivariate analysis of large prospective trials with homogeneous therapy will be required to determine the independent prognostic importance of these factors. Current treatment strategies in ALL include (1) tailoring therapy and its intensity to prognostic groups; (2) multiple-drug combinations in induction; (3) early use of intrathecal (IT) methotrexate (MTX); (4) CNS prophylaxis with IT MTX alone in good prognosis patients and combined cranial radiation (CXRT), 1800 rads plus IT MTX, in average and poor prognosis patients. Current studies show a CNS relapse rate of 5% in all prognostic groups. Late neuropsychological defects caused by cranial XRT and IT MTX have prompted programs designed to reduce the potential late toxicity of CNS prophylaxis. More pronounced in younger children, these abnormalities include decreased IQ, visual-motor incoordination, poor performance in mathematics, and memory dysfunction. Until 1980, more intensive induction, consolidation, and maintenance therapy had failed to prolong DFS in children with a poor prognosis. In West Germany (Berlin-Frankfurt-Muenster protocol) a 70 to 75% DFS is seen in all patients regardless of initial WBC, suggesting that effective therapy will override prognostic factors. Ultra-high-dose MTX, without cranial radiation, is also showing promise in poor prognosis patients. Other issues include the optimal duration of therapy, the role of testicular biopsies, and prophylactic testicular radiation. Recent studies suggest that prognostic factors lose their significance after 2 years of continuous complete remission and that 2 years of maintenance therapy is adequate. Bilateral open-wedge testicular biopsies have identified occult testicular disease in 8 to 10% of males. A unified approach to children with leukemia/lymphoma, a group with a particularly poor prognosis, utilizing NHL-type therapy may be more effective than conventional ALL therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Haemoglobin and prognosis in childhood acute lymphoblastic leukaemia

Two hundred and nine children presenting consecutively with acute lymphoblastic leukaemia to a regional paediatric oncology unit were investigated to determine the prognostic significance of various factors at diagnosis. There was a strong positive correlation between the pretreatment haemoglobin level and the percentage of bone marrow blast cells in S phase of the cell cycle as assessed by flow cytometry. Patients with T- and B-cell leukaemia had significantly higher haemoglobin levels than non-B non-T patients. In patients with total white cell counts less than 20 X 10(9)/l, aged less than 13 years, and no mediastinal mass, there was no association of haemoglobin with length of first remission. However, among those with white blood counts greater than 20 +/- 10(9)/l there was a strong positive trend towards shorter remission with higher haemoglobin levels. Children with high white blood counts at diagnosis and low haemoglobin levels may have a better prognosis than predicted by the white blood count alone.

A score at diagnosis for predicting length of remission in childhood acute lymphoblastic leukaemia

Thirty-two variables at diagnosis of acute lymphoblastic leukaemia (ALL) were studied in an unselected population-bases series of 209 children. Twelve variables had individually a statistically significant effect on the duration of first remission. A multivariate analysis using data on the 199 children who went into complete remission showed that all significant variation in remission times could be explained by only 3 variables acting simultaneously. These were the total white blood count (WBC) at diagnosis, the Franco-American-British (FAB) classification of blast morphology and the percentage of lymphoblasts with PAS+ coarse granules or blocks. A simple scoring system (for WBC add 1 if less than 20 X 10(9)/1, add 2 if 20 - 50 X 10(9)/1, add 3 if greater than or equal to 50 X 10(9)/1; for L2 or L3 leukaemia add 1; for PAS+ less than 5% add 1) separated patients into risk groups with widely different median lengths of first remission. Application of the risk score improves the prediction of the outcome of treatment, and the clinical trials, allows more accurate stratification, less extensive data collection and simpler analysis.