Cranial nerve involvement in typical and atypical chronic inflammatory demyelinating polyneuropathies.

BACKGROUND AND PURPOSE: Cranial nerve palsy is occasionally present in patients with chronic inflammatory demyelinating polyneuropathy (CIDP), but its prevalence, characteristics and relations with the CIDP subtypes have rarely been investigated. The aim of this study was to systematically assess cranial nerve involvement in typical and atypical CIDP. METHODS: Clinical data were reviewed in 132 consecutive patients with CIDP, including typical CIDP (n = 89), multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) (n = 31), distal acquired demyelinating symmetric (DADS) (n = 9) and others (n = 3). RESULTS: The frequency of cranial nerve palsy was 11% in typical CIDP, 48% in MADSAM and 11% in DADS. Facial and bulbar palsy was most frequently present (9%), followed by ocular motor nerve palsy (5%). Bilateral involvement was seen in all typical CIDP and DADS patients, whereas 80% of MADSAM patients had unilateral palsy. The presence of cranial nerve involvement was associated with more severe limb muscle weakness in typical CIDP, but not in MADSAM. Cranial nerve palsy fully recovered in 90% of typical CIDP and in 67% of MADSAM patients. CONCLUSION: Amongst the CIDP subtypes, cranial palsy is frequent and unilateral in MADSAM, and less frequent and bilateral in typical CIDP and DADS. In typical CIDP, facial and bulbar palsy reflects more severe and extensive inflammation.

How often and when Fisher syndrome is overlapped by Guillain-Barré syndrome or Bickerstaff brainstem encephalitis?

BACKGROUND AND PURPOSE: Fisher syndrome (FS) may overlap with Guillain-Barré syndrome (GBS), in particular the pharyngeal-cervical-brachial variant form (PCB-GBS), or Bickerstaff brainstem encephalitis (BBE). Our aim was to elucidate the frequency of this overlap and the patterns of clinical progression in patients with FS. METHODS: Sixty consecutive patients with FS were studied. FS/PCB-GBS was diagnosed when the patients developed pharyngeal, cervical and/or brachial weakness. Patients with flaccid tetraparesis were diagnosed as having FS/conventional GBS. FS/BBE was defined as the development of consciousness disturbances. RESULTS: All 60 patients initially developed the FS clinical triad alone (pure FS). Of these, 30 (50%) patients had pure FS throughout their course, whereas the remaining 50% of patients showed an overlap: PCB-GBS in 14 (23%) patients, conventional GBS in nine (15%) patients and BBE in seven (12%) patients. The median (range) durations from FS onset to progression to FS/PCB-GBS, FS/GBS or FS/BBE were 5 (1-7), 3 (1-4) and 3 (1-5) days, respectively. Patients with overlap syndromes more frequently received immune-modulating treatment, and the outcomes were generally favourable. The frequencies of positivity for anti-GQ1b, GT1a, GD1a, GD1b, GalNAc-GD1a and GM1 antibodies were not significantly different amongst the four groups. CONCLUSIONS: Of the patients with pure FS, 50% later developed an overlap with PCB-GBS, conventional GBS or BBE. The overlap occurred within 7 days of FS onset; thus, physicians should pay attention to the possible development of this overlap during the first week after FS onset.

POEMS syndrome with Guillan-Barre syndrome-like acute onset: a case report and review of neurological progression in 30 cases.

POEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes) syndrome is a rare cause of demyelinating neuropathy with monoclonal plasma cell proliferation, and POEMS neuropathy is usually chronically progressive. Herein, the authors report a 34-year-old woman with POEMS syndrome presenting as acute polyneuropathy. Within 2 weeks of disease onset, she became unable to walk with electrodiagnostic features of demyelination and was initially diagnosed as having Guillan-Barré syndrome. Other systemic features (oedema and skin changes) developed later, and an elevated serum level of vascular endothelial growth factor led to the diagnosis of POEMS syndrome. She received high-dose chemotherapy with autologous peripheral blood stem cell transplantation, resulting in good recovery. The authors also reviewed patterns and speed of progression of neuropathy in the 30 patients with POEMS syndrome; 22 (73%) of them were unable to walk independently with the median period of 9.5 months from POEMS onset (range 0.5-51 months). Whereas the speed of neuropathy progression varies considerably among patients, some POEMS patients can show acute or subacute polyneuropathy. The early diagnosis and treatment could result in rapid improvement as shown in the present patient.

Neuromuscular transmission is not impaired in axonal Guillain--Barré syndrome.

BACKGROUND: Previous studies have shown that anti-GQ1b antibodies induce massive neuromuscular blocking. If anti-GM1 and -GD1a antibodies have similar effects on the neuromuscular junction (NMJ) in human limb muscles, this may explain selective motor involvement in axonal Guillain--Barré syndrome (GBS). METHODS: Axonal-stimulating single-fibre electromyography was performed in the extensor digitorum communis muscle of 23 patients with GBS, including 13 with the axonal form whose sera had a high titre of serum IgG anti-GM1 or -GD1a antibodies. RESULTS: All patients with axonal or demyelinating GBS showed normal or near-normal jitter, and no blocking. CONCLUSION: In both axonal and demyelinating GBS, neuromuscular transmission is not impaired. Our results failed to support the hypothesis that anti-GM1 or -GD1a antibody affects the NMJ. In GBS, impulse transmission is presumably impaired in the motor nerve terminal axons proximal to the NMJ.

Eosinophilic differentiation of the human promyelocytic leukemia cell line, HL-60.

HL-60 promyelocytic leukemia cells differentiated to eosinophils and eosinophilic precursors when cultured under mildly alkaline conditions (pH 7.6-7.8) for 7 d without refeeding. New cytoplasmic granules appeared blue in the least mature cells and red in the most mature cells when stained with Wright-Giemsa. The granules also stained with Luxol-fast-blue, a characteristic of eosinophil granules. Furthermore, most cells contained the eosinophil major basic protein (MBP); the Charcot-Leyden Crystal (CLC) protein (lysophospholipase), eosinophil peroxidase, acid phosphatase, and arylsulfatase were also detected in a portion of these cells. The eosinophil major basic protein was found in a high proportion of undifferentiated cells, and thus may be constituitively produced. By examining finely banded chromosomes, translocation break points were demonstrated at q22 on one chromosome 16 and at q23 on the other homologue; abnormalities in this region of the long arm of 16 are a characteristic finding in the recently described syndrome of acute myelomonocytic leukemia (AMMoL) with abnormal bone marrow eosinophils. In common with the bone marrow eosinophils in these patients, the HL-60 eosinophil granules contained chloroacetate esterase and periodic-acid Schiff (PAS) reactive material; crystalloid inclusions were rare. Therefore, the HL-60 cell line appears to be an in vitro model for eosinophilopoiesis and may be specially suited for the study of the abnormal eosinophils seen in certain malignant conditions.

Thalidomide reduces serum VEGF levels and improves peripheral neuropathy in POEMS syndrome.

BACKGROUND: Polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes (POEMS) syndrome is a rare multi-system disorder associated with plasma-cell dyscrasia. Several case series and reports have suggested that high-dose chemotherapy with autologous peripheral blood stem-cell transplantation is efficacious treatment, but this transplantation is not indicated for elderly patients and patients with renal failure. OBJECTIVE: To investigate the effects of thalidomide treatment for POEMS syndrome. METHODS: Nine patients, who were not indicated for high-dose chemotherapy, were treated with thalidomide. Neurological disability scores, nerve conduction studies and serum levels of vascular endothelial growth factor (VEGF) were prospectively examined. VEGF levels were measured by an enzyme-linked immunosorbent assay. RESULTS: During follow-up periods of 8-23 months (mean, 15 months), all patients showed substantial clinical improvement (n = 6) or stabilisation of symptoms (n = 3). Serum VEGF levels decreased in all patients and were normalised in five patients. Nerve conduction velocities in the median nerve increased in seven patients. There were no serious adverse effects, including thalidomide neuropathy. CONCLUSION: Thalidomide treatment should be further studied as a treatment for POEMS syndrome, particularly for patients who are not indicated for transplantation therapy.

Bickerstaff's brainstem encephalitis and Fisher syndrome form a continuous spectrum: clinical analysis of 581 cases.

Whether Bickerstaff's brainstem encephalitis (BBE) is a distinct disease or a subtype of Fisher syndrome (FS) is unclear as there have been no clinical studies with sufficiently large numbers of patients with FS or BBE. Our aim was to clarify the nosological relationship. Medical records of patients suffering acute ophthalmoplegia and ataxia within four weeks of onset were reviewed. BBE was the diagnosis for patients with impaired consciousness, FS for those with clear consciousness and areflexia. Clinical features, neuroimages, and laboratory findings were analyzed. Patients were grouped as having BBE (n = 53), FS (n = 466), or as unclassified (n = 62). The BBE and FS groups had similar features; positive serum anti-GQ1b IgG antibody (68 % versus 83 %), antecedent Campylobacter jejuni infection (23 % versus 21 %), CSF albuminocytological dissociation (46 % versus 76 %), brain MRI abnormality (11 % versus 2 %), and abnormal EEG findings (57 % versus 25 %). BBE (n = 4) and FS (n = 28) subgroups underwent detailed electrophysiological testing. Both groups frequently showed absent soleus H-reflexes, but normal sensory nerve conduction (75 % versus 74 %) and a 1-Hz power spectrum peak on postural body sway analysis (67 % versus 72 %). Common autoantibodies, antecedent infections, and MRI and neurophysiological results found in this large study offer conclusive evidence that Bickerstaff's brainstem encephalitis and Fisher syndrome form a continuous spectrum with variable CNS and PNS involvement.

The ipsilateral cortico-spinal tract is activated after hemiparetic stroke.

BACKGROUND AND PURPOSE: The presence of a projection from the primary motor cortex to the ipsilateral muscles has been established in human, but whether this pathway contributes to functional recovery after stroke is unclear. We investigated whether the ipsilateral tract is activated in hemiparetic stroke. METHODS: Motor-evoked potentials (MEPs) were simultaneously recorded from the bilateral trapezius or abductor digiti minimi (ADM) muscles after magnetic stimulation to the motor cortex in 40 acute stroke patients. RESULTS: At rest, ipsilateral trapezius MEPs were recordable in none of the 24 normal controls, and in 38% of the patients after stimulation to the non-affected hemisphere (P < 0.001). With voluntary contraction, ipsilateral trapezius MEPs were elicited in 21% of the normal controls and 73% of the patients (P < 0.001). Ipsilateral ADM MEPs were rarely recordable in both controls (0%) and patients (3%). The presence of ipsilateral trapezius MEPs was associated with less severe paresis in the trapezius (P = 0.04) and deltoid (P = 0.07), but not in the more distal muscles. CONCLUSIONS: The ipsilateral cortico-spinal tract is acutely facilitated after stroke in the trunk or proximal muscles, but not in the hand muscles. Activation of such pathway appears to partly compensate motor dysfunction of the trunk/proximal muscles.

Double minute chromosomes in acute myeloblastic leukemia.

Two patients with acute myeloblastic leukemia (AML) with double minute chromosomes (dmins) are described. One patient had dmins in approximately one-third of bone marrow cells examined at diagnosis; no other karyotypic changes were observed. The dmins disappeared when the patient achieved a complete remission. The second patient developed acute leukemia as a second cancer, having previously received radiotherapy and chemotherapy for a breast carcinoma. At the time of diagnosis of AML, the patient exhibited dmins in 12% of bone marrow cells; other complex karyotypic changes were observed. Data on the clinical and cytogenetic features of these cases are compared with those of other reported cases of acute leukemia with dmins. The possible biologic and clinical significance of dmins in acute leukemia is discussed.

Nonrandom rearrangement of chromosome 14 at band q32.33 in human lymphoid malignancies with mature B-cell phenotype.

Chromosomes were studied in 61 patients with differentiated B-cell malignancies including 21 with non-Hodgkin's lymphoma (NHL), three with hairy cell leukemia (HCL), eight with Waldenström's macroglobulinemia (WM), and 29 with plasma cell disorder. Chromosomally abnormal clones were identified in 35 of 61 patients studied: all with NHL, all with HCL, three of eight with WM, and eight of 29 with plasma cell disorder. The most recurrent chromosomal abnormality, observed in 26 of the 35 patients whose chromosomes were abnormal, was a rearrangement involving chromosome 14, in which an additional segment was attached at band 32 in the long arm to form a 14q+ marker chromosome. This rearrangement was seen in 17 patients with NHL, three with HCL, one with WM, and five with plasma cell disorder. In NHL, the rearrangement correlates with histological subclasses: t(14;18) in all four patients with malignant lymphoma (ML)-follicular, mixed small cleaved and large cell; t(8;14) or its variant form, t(8;22), in all six with ML-small noncleaved cell; and t(11;14) in two of three with ML-diffuse, mixed small and large cell. A t(14;18) was also found in each patient with ML-diffuse, large cell, WM, and multiple myeloma, and a variant three-way translocation, t(5;18;14) (q13;q21;q32), in one with ML-diffuse, small cleaved cell. The donor sites for these 14q+ were assigned to oncogene loci: c-myc (8q24), bcl-1 (11q13), and bcl-2 (18q21). Moreover, the donor sites were also located near immunoglobulin light chain gene loci in each patient with leukemic ML-diffuse, mixed small and large cell, t(2;14) (p13;q32.3), and HCL, t(14;22)(q32.3;q11.2). These findings suggest that chimeric DNA formation, not only between an immunoglobulin gene and a certain oncogene, but also between the IgH gene and one of the IgL genes may be potentially relevant in malignant B-cell proliferation.

Frequent p53 gene mutations in blast crisis of chronic myelogenous leukemia, especially in myeloid crisis harboring loss of a chromosome 17p.

We investigated chromosome alterations and mutations of the p53 gene in 118 samples from 92 patients with chronic myelogenous leukemia in various clinical phases, i.e., chronic phase, accelerated phase, and blast crisis (BC). Single-strand conformation polymorphism analysis and subsequent nucleotide sequencing disclosed no alteration of the p53 gene in chronic phase (no mutation in 80 samples), while five of 31 BC samples showed point mutations: four in myeloid and one in lymphoid crisis. One of seven accelerated phase samples also showed a p53 gene mutation. Ten of 31 BC samples showed loss of one of the short arms of chromosome 17 (17p) through the formation of isochromosome 17q, i(17q), or unbalanced translocations. Loss of heterozygosity at the p53 locus in the accelerated phase and BC was detected only in two cases with i(17q) but not in seven cases with normal chromosome 17 homologues, suggesting that loss of one p53 allele is rare without cytogenetically detectable loss of a 17p. Among those six samples with p53 gene mutations, five showed loss of a 17p cytogenetically, and only one lymphoid crisis case exhibited normal chromosome 17 homologues. Thus, mutations of the p53 gene were closely associated with myeloid crisis with loss of a 17p (four mutations in ten samples), in contrast to myeloid crisis with normal chromosome 17 homologues (zero in 13) or lymphoid crisis (one in seven). Our results also suggest that alterations of the p53 gene might occur after loss of a 17p during the course of chronic myelogenous leukemia.

Chromosomal alterations in acute leukemia patients studied with improved culture methods.

Cytogenetic studies, using improved short-term culture techniques, were performed on 64 patients with acute leukemia to determine the incidence and kinds of clonal karyotypic changes detectable with this newer methodology. An adequate number of analyzable mitoses was obtained from 59 patients. Clonal chromosomal alterations were found in 88% (52 of 59) of patients, as compared to approximately 50% in previous studies of acute leukemia in which conventional techniques were used. From our series, abnormal karyotypes were detected in 37 of 44 (84%) cases with primary acute nonlymphocytic leukemia, all 5 with secondary acute nonlymphocytic leukemia, and all 10 with acute lymphoblastic leukemia. Among the entire group of patients, several recurrent abnormalities were observed, e.g., -7 in eight cases, +8 in seven cases, t(15;17) in four cases, and t(8;21) or a variant of this translocation in four cases. In five patients, the only abnormality was a rather subtle structural rearrangement (e.g., tiny deletion). Five other patients had clonal changes which were found in less than 10% of the mitoses examined in each case. Our results indicate that most patients with acute leukemia, both acute nonlymphocytic leukemia and acute lymphoblastic leukemia, have clonal chromosome abnormalities associated with their disease.

Cloning of cDNA for rat eosinophil major basic protein.

We have determined the complete nucleotide sequence for the cDNA encoding rat eosinophil major basic protein (MBP) using the rapid amplification of cDNA ends (RACE) procedure. The deduced amino acid sequence revealed that the rat prepro-MBP has three functional domains, namely the signal peptide, the acidic peptide that contains numerous acidic amino acids, and the mature MBP, as in human and guinea pig MBP.

Abnormalities of chromosome 16 in association with acute myelomonocytic leukemia and dysplastic bone marrow eosinophils.

Six patients with M4 acute myelomonocytic leukemia ( AMMoL ) were identified who had abnormalities of chromosome 16 in bone marrow cells. Five had a pericentric inversion, inv(16)( p13q22 ), and a sixth patient had a translocation, t(16;16)(p13.1;q22). Each of these six patients had bone marrow eosinophils that were abnormal in morphology on light and/or electron microscopy and by cytochemical stains. The eosinophils constituted 1%-24% of nucleated marrow cells. Of 61 acute nonlymphocytic leukemia (ANLL) patients, all those with AMMoL and abnormal bone marrow eosinophils had an inv(16) or a t(16;16). One other patient in this group had a rearrangement of chromosome 16 (with a break in the short arm at band p13); however, the ANLL type was M1 and no abnormal eosinophils were present. Four patients with ANLL types other than M4 had an increase in marrow eosinophils; three in whom the eosinophils appeared normal and one with ANLL-M2 and bizarre eosinophils morphologically distinct from those seen in AMMoL . Chromosome pair 16 was normal in the latter four patients. AMMoL with dysplastic bone marrow eosinophils appears to represent a unique clinicopathologic entity associated with several related abnormalities affecting 16q . The morphologic features of both blasts and eosinophils may be more important than the absolute number of eosinophils in the marrow in identifying this group of patients. This may have prognostic importance as five of six patients achieved complete remission with standard antileukemic therapy and are still alive.

Absence in Ph-negative, M-BCR rearrangement-positive chronic myelogenous leukemia of linkage between 5' ABL and 3' M-BCR sequences in Philadelphia translocation.

The Philadelphia (Ph) chromosome can be detected in the vast majority of patients with chronic myelogenous leukemia (CML). We performed a long-range analysis of chromosomal translocation junction by pulsed-field gel electrophoresis (PFGE) techniques, to examine whether molecular evidence of a reciprocal Ph translocation exists in Ph-positive CML as well as Ph-negative, M-BCR rearrangement-positive CML. The rearrangement within M-BCR and ABL was detected in all patients including nine Ph-positive CML, and three Ph-negative CML. The rearranged 3'-abl fragments showed comigration with rearranged 5'-bcr fragment in rare-cutting restriction enzyme digests in all patients with Ph-positive CML. Thus, the physical linkage of the 3' part of ABL to the 5' side of M-BCR on 22q-chromosome was shown. The same linkage was also demonstrated in all three patients with Ph-negative CML. Meanwhile, the rearranged 3'-bcr fragments showed comigration with rearranged pHabl5' (or T39-1-2) fragments in all patients with Ph-positive CML, indicating the linkage of the 5' end of ABL to the 3' part of M-BCR on 9q+ chromosome. However, this linkage was absent in two Ph-negative CML patients who could be studied. The results suggest that a genomic insertion of 3' ABL into M-BCR in Ph-negative CML occurs by a single cytogenetic event rather than a two-translocation mechanism.

Microsatellite instability is an early genetic event in myelodysplastic syndrome but is infrequent and not associated with TGF-beta receptor type II gene mutation.

We examined microsatellite instability (MSI) at 10 loci of dinucleotide repeats using the polymerase chain reaction (PCR) in patients with myelodysplastic syndrome (MDS). Bone marrow DNA was obtained from 45 patients repeatedly during the disease course and fibroblast DNA was also collected from 19 of them as a normal control. Three of the 19 patients showed an alteration at more than three loci, when the allele length was compared between their fibroblast DNA and the initial marrow DNA. On the other hand, none of the 45 patients showed an alteration when the initial sample was compared with the latest one. One of the three patients with MSI had refractory anemia and two refractory anemia with ring sideroblasts and none of them showed disease progression, complex chromosome abnormality, karyotypic evolution, or mutation of N-RAS or TP53. Moreover, a frameshift mutation within 10 repeating adenines of transforming growth factor beta type II receptor gene, which was recently recognized as a critical target of MSI, was not found in any of the patients including the three with MSI. These findings suggest that MSI is an early but infrequent genetic event and is independent of other critical genetic aberrations in the development of MDS.

Genetic aberrations in the development and subsequent progression of myelodysplastic syndrome.

We performed longitudinal analyses of chromosomes and studied the configuration of NRAS, TP53, NF1, and cFMS genes in 70 patients with myelodysplastic syndrome(MDS). The NRAS mutations were detected in 6 patients(9%) at codons 12 or 13. The TP53 mutations were found in 10 patients(14%) in exons 4 through 8. Longitudinal studies revealed that the NRAS mutation was a late-appearing event, while the TP53 mutations were detectable at the presentation of MDS. No patients had both NRAS and TP53 mutations, simultaneously. NF1 and cFMS genes showed any mutational event among these 70 patients. Patients with a TP53 mutation had a significantly shorter survival time than those with an NRAS mutation or those without NRAS or TP53 mutation. However, patients who showed an NRAS mutation had a shorter survival time once the mutation emerged, similar to that of patients with a TP53 mutation.

Primary acute myeloid leukemia cells negative for c-kit receptor protein expression do not proliferate in vitro in response to colony-stimulating factors.

This study examined the effects of recombinant human stem cell factor (SCF) alone or in combination with colony-stimulated factors (CSFs) on colony formation of leukemic progenitors obtained from 29 acute myeloid leukemia (AML) patients. C-kit receptor (c-kitR) protein expression was examined using an immunofluorescence method and was detected on more than 10% of leukemic cells in 20 of 29 cases (c-kitR+). SCF alone could stimulate formation of colonies in 14 of 20 c-kitR+ cases. Granulocyte(G)-CSF, granulocyte-macrophage (GM)-CSF, and interleukin (IL)-3 alone stimulated colony growth in 18, 17 and 16 of c-kitR+ cases, respectively. In contrast, colony and cluster formations from eight of nine c-kitR- cases was not stimulated at all by SCF alone nor SCF in combination with CSF nor with any CSF alone. However, the in vitro culture behavior of fluorescence-activated cell sorter-sorted c-kitR- cells from c-kitR+ cases did not significantly differ from c-kitR+ cells. These results suggest that responses of leukemic progenitors to CSFs were variable but may be predicted by their c-kitR expressions, and that c-kitR(-) cases may have a different disease entity from c-kitR(+) cases.

Prospective monitoring of minimal residual disease during the course of chemotherapy in patients with acute lymphoblastic leukemia, and detection of contaminating tumor cells in peripheral blood stem cells for autotransplantation.

A prospective study for detecting minimal residual disease (MRD) was conducted on children with acute lymphoblastic leukemia (ALL). Thirty-nine patients (38 B-lineage ALL, one T-ALL) with TCR delta rearrangements could be followed for 21 to 44 months (mean 30.9 months) excluding four patients who died. One hundred and ninety four bone marrow (BM) samples and 13 peripheral blood stem cell (PBSC) grafts were available for detection of MRD. Initially 34 cases were treated prospectively according to the CCLSG risk-stratified protocols for ALL (ALL874 or ALL911), and five cases according to the other protocols. Conventional chemotherapy was replaced by autologous PBSC transplantation (PBSCT) in five patients, by allogenic BM transplantation (BMT) in one patient, or suspended in another patient. Twenty-nine of 32 children in whom conventional chemotherapy could be continued without interruption remain in complete remission (CR). In 24 of the 29 patients MRD became undetectable within 12 months of their diagnosis. In five cases, BM samples obtained during maintenance therapy exhibited residual leukemia cells, and yet none of them relapsed (mean follow-up period 28.6 months). Our results thus indicate that intensive maintenance therapy for patients with PCR-positive results during consolidation therapy may prevent subsequent relapse. Nine events of relapse were diagnosed in eight patients (five BM, two isolated central nervous system (CNS), one combined BM and CNS, one isolated skin relapse). An increase or a re-emergence of MRD was detected in BM samples obtained from patients prior to BM relapse, but one patient remained in CR despite reappearance of leukemic cells following a PCR-negative status. Monitoring of MRD failed to predict isolated CNS or skin relapse. PBSCT allows high-dose cytoreduction therapy for patients with refractory neoplasia. In our study, leukemic cells were identified in eight of 13 PBSC grafts harvested from five patients. Three of four children who received PBSC grafts containing leukemic cells relapsed within 6 months after PBSCT. Monitoring of MRD as part of quality control of PBSC grafts may ultimately contribute to improvements in PBSCT procedures.

Alterations of CDKN2 gene structure in childhood acute lymphoblastic leukemia: mutations of CDKN2 are observed preferentially in T lineage.

We analyzed homozygous deletions and mutations of the CDKN2(p16(INK4A)/MTS1) gene, using polymerase chain reaction and Southern blot analysis, in 120 children with acute lymphoblastic leukemia (ALL). Homozygous deletion was found in 17 of 89 (19%) precursor B-ALL patients, in 11 of 24 (46%) T-ALL patients, and in 0 of 7 other phenotype ALL patients. After excluding 28 (23%) patients who showed a homozygous deletion of CDKN2, we found that three patients (3%) had mutation at exon 2 of CDKN2 using PCR-SSCP and sequencing strategy. One had a CGA to TGA nonsense mutation (Arg to stop) at codon 72, one had a 1-bp deletion at codon 117, and the third had a 2-bp deletion at codon 70, resulting in frameshifts in the two latter patients. All three of these patients were T phenotype ALL, and the incidence of mutation in the 24 T-ALL patients examined was 13%. In contrast, no mutation was detected in the remaining patients with precursor-B or other type ALL (0/96). Our results suggest that mutational inactivation of the CDKN2 gene may contribute to the leukemogenic growth, especially in some patients with T-ALL.