Recovery of cognitive function after relapse in multiple sclerosis.

BACKGROUND: Cognitive impairment is common in multiple sclerosis (MS) but its manifestation as acute disease activity is underappreciated. OBJECTIVE: The aim of this study is to examine recovery after MS relapse on multiple tests of cognitive and motor function and explore correlates of change with Expanded Disability Status Scale (EDSS), magnetic resonance imaging (MRI), and cognitive reserve. METHODS: Fifty relapsing group (RG) and matched stable participants were examined at baseline, during relapse, and at 3-month follow-up. Tests of cognitive processing speed (Symbol Digit Modalities Test (SDMT)) and consensus opinion measures of memory, ambulation, and manual dexterity were administered. All RG patients were treated with a 5-day course of Acthar Gel (5 mL/80 IU). RESULTS: In RG patients, SDMT declined from 55.2 to 44.6 at relapse and recovered to 51.7, a slope differing from stable controls (p = 0.001). A statistical trend (p = 0.07) for the same effect was observed for verbal memory and was significant for ambulation (p = 0.03). The Cerebral Function Score from the EDSS also changed in the RG and recovered incompletely relative to controls (p = 0.006). CONCLUSION: These results replicate earlier reports of cognitive worsening during relapse in MS. Clinically meaningful improvements followed relapse on SDMT and ambulation. Cognitive decline during relapse can be appreciated on neurological exam but not patient-reported outcomes.

Necessity of technicians for computerized neuropsychological assessment devices in multiple sclerosis.

OBJECTIVE: Determine the influence of technician supervision on computer-administered cognitive tests in multiple sclerosis (MS). METHODS: Eighty MS patients underwent assessment using the CogState Brief Battery (CSBB) and the Cleveland Clinic Cognitive Battery (C3B). Each was administered twice, once with a technician guiding assessment, and once with technician-absent. Twenty-eight healthy controls were also evaluated. RESULTS: The influence of technician guidance was not statistically significant for group means on either test. For CSBB, administration problems were more common in the technician-absent condition. CONCLUSION: In this MS sample, reliable and valid test results were obtained from computer-assisted cognitive testing without technician guidance.

Dalfampridine benefits ambulation but not cognition in multiple sclerosis.

BACKGROUND: Impaired cognition and ambulation are common in multiple sclerosis (MS). Dalfampridine is the first Food and Drug Administration (FDA)-approved medication to treat impaired ambulation in MS. Dalfampridine may benefit patients with cognitive impairment, given its effects on saltatory conduction and the association between cognitive and motor function. OBJECTIVE: To examine the effects of dalfampridine on cognition in MS. To determine if the anticipated improved cognition is grounded in dalfampridine's effects on ambulation. METHODS: Adults with MS were randomized to dalfampridine (n = 45) or placebo (n = 16) for 12 weeks. Cognition and motor function were assessed at baseline and end-point. RESULTS: T25FW and 6-minute walk (6MW) performance improved at end-point in the treatment group but not in the placebo group (p < 0.05). Our primary outcome, performance on the Symbol Digit Modalities Test, did not improve. About 30% (n = 12) of the dalfampridine group demonstrated ⩾20% improved ambulation and were categorized "responders." Among "responders", Symbol Digit Modalities test performance did not improve. However, performance on the Paced Auditory Serial Addition Test improved among "responders" (p < 0.05). CONCLUSION: Dalfampridine benefits timed ambulation but not cognition. Some improvement among ambulation "responders" is consistent with prior reports of cognition-motor coupling in MS ( ClinicalTrials.gov #: NCT02006160).

Preliminary investigation of cognitive function in aged multiple sclerosis patients: Challenges in detecting comorbid Alzheimer's disease.

BACKGROUND: Cognitive impairment can be seen in patients of all ages with multiple sclerosis (MS). However, there is limited research on neurocognitive disorder in older adults with MS and how to detect Alzheimer's disease (AD) or its prodromal stage, amnestic mild cognitive impairment (aMCI). Thus, the MS clinician is challenged to discriminate between signs of MS-related cognitive decline versus a secondary neurodegenerative process. OBJECTIVE: Compare cognition in older MS patients to patients with AD and aMCI. METHODS: We evaluated cognitively impaired and unimpaired MS patients, AD patients, aMCI patients, and healthy controls (HCs), all elderly (n = 20 per group). AD and aMCI diagnoses were derived by consensus conference independent of the MS research project. Neuropsychological measures assessed domains commonly affected in AD, including verbal memory and expressive language. RESULTS: Cognitively impaired and unimpaired MS groups did not differ on any measures sensitive to AD. Unimpaired MS patients were comparable to HCs. Impaired MS patients showed decreased semantic fluency, similar to aMCI patients. Lastly, while both AD and aMCI groups had deficient memory retention, there was no evidence of a retention deficit in either MS group. CONCLUSION: Our findings suggest that the cognitive profiles of MS and AD are distinct. In contrast to AD, MS is not associated with impairment of memory consolidation. However, there may be overlap between cognitive deficits related to MS and aMCI. Thus, evidence of poor memory retention, in an older MS patient may merit comprehensive dementia evaluation. The study is preliminary and includes no AD biomarkers (e.g., amyloid imaging) to confirm or rule out AD pathology.

Longitudinal personality change associated with cognitive decline in multiple sclerosis.

We previously reported that personality and cognition were stable over 3 years in patients with multiple sclerosis (MS). This study examined whether a longer duration would reveal evidence of emerging personality dysfunction. The NEO Five-Factor Inventory and Brief International Cognitive Assessment for MS was used to assess personality and cognition, respectively. Patients were classified as "Cog Stable" or "Cog Decline" based on cognitive deterioration over 5 years. Extraversion and Conscientiousness declined across pooled groups. Follow-up of a group by time interaction found that decline in these traits was more evident in the Cog Decline group, demonstrating a link between personality and cognitive change.

Remote assessment of verbal memory in MS patients using the California Verbal Learning Test.

We used the California Verbal Learning Test, Second Edition (CVLT-II), one component of the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS), to determine feasibility of a remote assessment protocol. We compared telephone-administered CVLT-II data from MS patients to data acquired in person from an independent sample of patients and healthy controls. Mixed factor analyses of variance (ANOVAs) showed no significant differences between patient groups, but between-group effects comparing patients and healthy controls were significant. In this study, CVLT-II assessment by conventional in-person and remote telephone assessment yielded indistinguishable results. The findings indicate that telephone-administered CVLT-II is feasible. Further validation studies are underway.

Trait neuroticism, extraversion, and conscientiousness in multiple sclerosis: Link to cognitive impairment?

BACKGROUND: Previous research suggests that patients with multiple sclerosis (MS) have higher neuroticism, lower extraversion, and lower conscientiousness relative to healthy controls (HCs). However, the prevalence of this maladaptive profile in MS and its relation to cognition is unknown. OBJECTIVE: Determine prevalence of maladaptive personality among MS patients, compared to HCs, and examine how it relates to cognitive dysfunction. METHODS: A sample of 275 MS patients and 55 HCs completed neuroperformance measures of information processing speed and memory. Self and informant ratings were obtained on the NEO Five-Factor Inventory. RESULTS: MS patients had higher neuroticism and lower extraversion than HCs. Cognitively impaired patients were also lower in conscientiousness. Cluster analysis revealed a configuration of these same three traits, representing a maladaptive profile. This profile was found in 50% of the overall MS sample, compared to 24% of HCs. However, only cognitively impaired MS patients had a higher prevalence of maladaptive personality compared to HCs. Among cognitively impaired patients, those with maladaptive traits were impaired in more cognitive domains than those with more adaptive traits. CONCLUSION: Cognitively impaired MS patients have a higher prevalence of seemingly maladaptive traits compared to HCs, demonstrating an association between cognition and personality in MS.

Differential effects of aging on motor and cognitive functioning in multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) patients are impaired in motor and cognitive performance, but the extent to which these deficits are magnified by aging is unknown. In one prior study, differences in cognitive processing speed between MS patients and healthy individuals were of similar magnitude across the lifespan. Here, we have improved on this work by expanding assessment to multiple cognitive domains and motor functioning. OBJECTIVE: To determine whether the degree of cognitive and motor dysfunction in MS is magnified with increasing age. METHODS: In all, 698 MS patients (aged 29-71 years) and 226 healthy controls (HCs; aged 18-72 years) completed neuroperformance tests covering ambulation, upper extremity function, information processing speed, and memory. RESULTS: Linear regression models predicting cognitive and motor function revealed main effects of MS/HC diagnosis, age, and education across all measures. There was also an interaction between age and diagnosis on measures of motor function, but not on cognitive outcomes. CONCLUSION: The progression of motor decline is amplified by aging in MS. However, the degree of cognitive impairment does not vary across the lifespan. Thus, evidence of accelerated cognitive impairment in older adults with MS may signal the presence of other age-related cognitive pathologies.

Latent profile analysis of regression-based norms demonstrates relationship of compounding MS symptom burden and negative work events.

OBJECTIVE: We endeavored to clarify how distinct co-occurring symptoms relate to the presence of negative work events in employed multiple sclerosis (MS) patients. Latent profile analysis (LPA) was utilized to elucidate common disability patterns by isolating patient subpopulations. METHOD: Samples of 272 employed MS patients and 209 healthy controls (HC) were administered neuroperformance tests of ambulation, hand dexterity, processing speed, and memory. Regression-based norms were created from the HC sample. LPA identified latent profiles using the regression-based z-scores. Finally, multinomial logistic regression tested for negative work event differences among the latent profiles. RESULTS: Four profiles were identified via LPA: a common profile (55%) characterized by slightly below average performance in all domains, a broadly low-performing profile (18%), a poor motor abilities profile with average cognition (17%), and a generally high-functioning profile (9%). Multinomial regression analysis revealed that the uniformly low-performing profile demonstrated a higher likelihood of reported negative work events. CONCLUSIONS: Employed MS patients with co-occurring motor, memory and processing speed impairments were most likely to report a negative work event, classifying them as uniquely at risk for job loss.

Impact of Pharmacotherapy on Cognitive Dysfunction in Patients with Multiple Sclerosis.

Cognitive impairment is a common symptom of multiple sclerosis (MS), adversely impacting many spheres of daily functioning. Yet the effectiveness of pharmacological interventions for cognitive impairment in MS is unclear. Clinicians and patients alike would benefit from formal guidelines regarding effective management of cognitive symptoms. We reviewed the background on the measurement, pathophysiology and risk factors for cognitive dysfunction in MS, and then examined the published clinical trials of pharmacotherapy, including both disease-modifying treatments (DMTs) and symptom-management therapies (SMTs). Our review of DMTs revealed only a single well-designed, randomized, controlled trial where intramuscular interferon (IFN)-ß1a, administered once weekly, was compared with placebo. The results showed significant benefits in terms of cognitive processing speed and memory. Less convincing but promising data have shown the potential benefits of IFN-ß1b and natalizumab. The literature on SMTs is replete with placebo-controlled, single-centre studies, with a failure to replicate initially promising results. The results for SMTs such as acetylcholinesterase inhibitors and psychostimulants are mixed. Some encouraging data show promise but not to a threshold of indication for standard clinical use. Numerous methodological factors hamper research in this area. Acknowledging the lack of firm conclusions, we argue that all DMTs are likely to benefit cognition and that, if otherwise safe, SMTs with some empirical support may be attempted at the discretion of the treating clinician. We offer some guidance on the assessment and monitoring of cognitive function to inform off-license treatment of cognitive impairment in MS patients.

Benchmarks of meaningful impairment on the MSFC and BICAMS.

BACKGROUND: Cognitive and motor abilities in multiple sclerosis (MS) are typically quantified using reliable, consensus standard tests validated in the MS population. While these performance measures are associated with vocational disability in parametric analyses, translation of raw scores into anchors reflecting clinically relevant, functional impairment requires further research. OBJECTIVE: To examine performance-based motor and cognitive outcomes among definitive anchors that designate varying degrees of functional impairment, thereby establishing benchmarks for score interpretation. METHODS: We evaluated MS patients and healthy controls, all undergoing a brief test battery. Outcomes were derived from the MS Functional Composite (MSFC) and the Brief International Cognitive Assessment for MS (BICAMS). Functional impairment anchors were (1) disability benefits, (2) employed with negative work events, and (3) employed without problems. RESULTS: All measures yielded statistically significant differences across all levels of work status, after accounting for the effects of age and education. Benchmark values distinguished the functional impairment groups. When evaluated in combination, the Timed 25-Foot Walk and the Symbol Digit Modalities Test were the most robust predictors of functional decline. CONCLUSION: We have established benchmark scores for popular motor and cognitive tests that are associated with specific degrees of impairment in work status.

Stable neuropsychiatric status in multiple sclerosis: a 3-year study.

Personality changes and neuropsychiatric symptoms are found in multiple sclerosis (MS), but no study has evaluated decline compared to healthy controls. This study assessed personality traits and neuropsychiatric symptoms over 3 years using the NEO Five Factor Inventory and the Neuropsychiatric Inventory. Additional metrics evaluated ambulation, manual dexterity and cognitive function. Contrary to hypothesis, patients showed no significant change in personality or neuropsychiatric status relative to controls. Patients were impaired in motor and cognitive function at baseline and follow-up, but showed only slowing in ambulation over time. The findings indicate that neuropsychiatric status is stable in MS over 3 years.

High-mobility group box 1 in multiple sclerosis.

This study is one in series determining the potential of RAGE axis (receptor for advanced glycation end products, isoforms, ligands) as a biomarker in multiple sclerosis (MS). We evaluated serum levels of RAGE ligand, the high-mobility group box (HMGB)1 in MS patients, and assessed the correlation between HMGB1 serum levels and the use of disease-modifying drugs (DMDs), and between HMGB1 serum levels and indicators of MS disease severity. HMGB1 serum levels were compared between 96 (23 males) MS patients and 34 age- and gender-matched healthy controls (HCs) using enzyme-linked immunosorbent assays. DMD-naïve MS patients had significantly higher HMGB1 serum levels compared with DMD-treated (P = 0.04) and compared with HCs (P = 0.01). HMGB1 serum levels were not significantly different between total MS patients (DMD-naïve plus DMD-treated) and HCs (P = 0.09). DMD-naïve MS patients in clinical relapse tended to have lower HMGB1 serum levels than clinically stable RRMS patients (P = 0.07). HMGB1 serum levels showed 0.65 area under the curve (95 % CI 0.55-0.95) sensitivity/specificity for MS clinical relapse. The role of HMGB1 in MS disease pathology and DMD modulation of this protein warrant further investigations.

Negative work events reported online precede job loss in multiple sclerosis.

PURPOSE: Determine if a recently validated online survey of negative work events can predict future job loss among multiple sclerosis (MS) patients. METHOD: Evaluated were 284 employed individuals (63 healthy controls, 221 MS patients), every three months, using an online vocational monitoring tool. Job loss rates in MS patients were compared with the healthy controls. Survey responses from MS patients suffering job loss (n=23) were then compared to those maintaining employment. Analyses focused on the frequency of negative work events. RESULTS: While 23 (10%) of MS patients lost their job after baseline, there was no job loss among the healthy controls. Compared to stably employed patients, those suffering job loss had been diagnosed with MS later in life, were more likely to report a progressive disease course, and had greater physical disability as measured by the Patient Derived Disease Steps (PDDS). Declining patients were also more likely to report negative work events within three months of job loss (e.g., verbal criticism for errors or removal of responsibilities). Stepwise logistic regression predicting MS job loss retained the PDDS, age at diagnosis, years working for employer and reporting a negative work event. CONCLUSIONS: The results show that physical disability and patient reported risk factors for job loss can be monitored using an online survey tool. The tool can trigger clinical assessments to help prevent unemployment and assist patients in procuring disability benefits.

Disease modifying drugs modulate endogenous secretory receptor for advanced glycation end-products, a new biomarker of clinical relapse in multiple sclerosis.

OBJECTIVES: This study is one in a series measuring RAGE axis (receptor for advanced glycation end products, its isoforms, and ligands) and its potential as a biomarker in multiple sclerosis (MS). We evaluated serum levels of the endogenous secretory RAGE (esRAGE) in MS patients and assessed the relationship between esRAGE levels and the use of disease modifying drugs (DMDs), and between esRAGE levels and indicators of MS disease severity. METHOD: esRAGE serum levels were compared between 98 MS patients and 34 healthy controls (HCs) using ELISA. RESULTS: esRAGE serum levels were similar between MS and HCs. DMD-treated patients had higher esRAGE serum levels than DMD-naïve patients (395.7±38.6pg/ml vs. 299.2±20.1pg/ml, P=0.02). DMD-naïve, primary progressive (PP) patients had higher esRAGE serum levels, than relapsing remitting (RR) (P=0.02) and secondary progressive (SP) (P=0.04) patients; RRMS patients in clinical relapse had lower esRAGE serum levels than clinically stable patients (219.7±30.0pg/ml vs. 338.2±31.6pg/ml, P=0.02). In a univariate regression analysis of DMD-naïve MS patients, esRAGE serum levels inversely correlated with the rate of clinical relapse (r=-0.44, P=0.006), MS severity scale (MSSS) (r=-0.32, P=0.03), and expanded disability status scale (EDSS) (r=-0.251, P=0.07). CONCLUSION: esRAGE serum levels are modulated by DMDs. The serum levels may be a useful biomarker of MS clinical relapse.

Quantitative and qualitative pleiotropic differences between Simvastatin single and Vytorin combination therapy in hypercholesterolemic subjects.

AIMS: This cross-sectional study tested the hypothesis that treatment with the combination of Ezetimibe/Simvastatin (Vytorin) leads to broader changes in the expression levels of immunomodulatory genes as compared to Simvastatin monotherapy. METHODS: Illumina's GenomeStudio gene expression module was used to compare gene profiles of Vytorin and Simvastatin in the peripheral blood mononuclear cells of 20 hypercholesterolemic subjects. RESULTS: The characteristics of the immunomodulatory genes, which were altered by Vytorin, differed from those genes which were altered by Simvastatin. Vytorin mostly altered the expression levels of genes related to inflammation/oxidative stress; it downregulated the NF-KappaB and upregulated the expression of anti-inflammatory cytokine, IL-10, and anti-oxidant enzymes, GPX1 and SOD2, but also upregulated the expression levels of genes involved in cellular activation, adhesion, and coagulation cascade, including VWF, F7, PF4, PF4V1 SELP, ITGB3, ITGB5. Simvastatin mostly altered the expression levels of genes related to cellular apoptosis/proliferation. It upregulated the expression levels of apoptosis-related genes APAF1, BAX, IER3, and CSF1R, and downregulated the expression levels of genes related to cellular proliferation, including PTN and CD69. Treatment with Vytorin combination therapy modulated lipid profile and serum levels of the C-reactive protein more effectively, than treatment with Simvastatin monotherapy. CONCLUSION: The nature of the pleiotropic effects may play a role in Vytorin's and Simvastatin's clinical efficacies.

Serum lipid profiles are associated with disability and MRI outcomes in multiple sclerosis.

BACKGROUND: The breakdown of the blood-brain-barrier vascular endothelium is critical for entry of immune cells into the MS brain. Vascular co-morbidities are associated with increased risk of progression. Dyslipidemia, elevated LDL and reduced HDL may increase progression by activating inflammatory processes at the vascular endothelium. OBJECTIVE: To assess the associations of serum lipid profile variables (triglycerides, high and low density lipoproteins (HDL, LDL) and total cholesterol) with disability and MRI measures in multiple sclerosis (MS). METHODS: This study included 492 MS patients (age: 47.1 ± 10.8 years; disease duration: 12.8 ± 10.1 years) with baseline and follow-up Expanded Disability Status Score (EDSS) assessments after a mean period of 2.2 ± 1.0 years. The associations of baseline lipid profile variables with disability changes were assessed. Quantitative MRI findings at baseline were available for 210 patients. RESULTS: EDSS worsening was associated with higher baseline LDL (p = 0.006) and total cholesterol (p = 0.001, 0.008) levels, with trends for higher triglyceride (p = 0.025); HDL was not associated. A similar pattern was found for MSSS worsening. Higher HDL levels (p < 0.001) were associated with lower contrast-enhancing lesion volume. Higher total cholesterol was associated with a trend for lower brain parenchymal fraction (p = 0.033). CONCLUSIONS: Serum lipid profile has modest effects on disease progression in MS. Worsening disability is associated with higher levels of LDL, total cholesterol and triglycerides. Higher HDL is associated with lower levels of acute inflammatory activity.

Predicting loss of employment over three years in multiple sclerosis: clinically meaningful cognitive decline.

Cognitive dysfunction is common in multiple sclerosis (MS), yet the magnitude of change on objective neuropsychological (NP) tests that is clinically meaningful is unclear. We endeavored to determine NP markers of the transition from employment to work disability in MS, as indicated by degree of decline on individual tests. Participants were 97 employed MS patients followed over 41.3 ± 17.6 months with a NP battery covering six domains of cognitive function. Deterioration at follow-up was designated as documented and paid disability benefits (conservative definition) or a reduction in hours/work responsibilities (liberal definition). Using the conservative definition, 28.9% reported deteriorated employment status and for the liberal definition, 45.4%. The Symbol Digit Modalities Test (SDMT) and California Verbal Learning Test, Total Learning (CVLT2-TL) measures distinguished employed and disabled patients at follow-up. Controlling for demographic and MS characteristics, the odds ratio of a deterioration based on a change of 2.0 on the CVLT2-TL was 3.7 (95% CI 1.2-11.4 and SDMT by 4.0 was 4.2 (95% CI 1.2-14.8), accounting for 86.7% of the area under the ROC curve. We conclude that decline on NP testing over time is predictive of deterioration in vocational status, establishing a magnitude of decline on NP tests that is clinically meaningful.

Immunomodulatory responses of peripheral blood mononuclear cells from multiple sclerosis patients upon in vitro incubation with the flavonoid luteolin: additive effects of IFN-beta.

The study is aimed to determine the role of luteolin (3',4',5,7-tetrahydroxyflavone), alone and in combination with human interferon-beta (IFN-beta), in modulating the immune response(s) of peripheral blood mononuclear cells (PBMCs) isolated from multiple sclerosis (MS) patients. PBMC proliferation in the presence or absence of these drugs was determined and the production of pro-inflammatory cytokines (IL-1beta, TNF-alpha), and the ratio of cell migration mediator MMP-9, and its inhibitor, TIMP-1 was assessed in the culture supernatants. Luteolin reduced, in a dose-dependent manner, the proliferation of PBMCs, and modulated the levels of IL-1beta and TNF-alpha released by PBMCs in the culture supernatants. Luteolin reduced the MMP-9/TIMP-1 ratio via lowering MMP-9 production. In the majority of cases, luteolin, when combined with IFN-beta, had additive effects in modulating cell proliferation, IL-1beta, TNF-alpha, MMP-9 and TIMP-1.

Targeting 11q23 positive acute leukemia cells with high molecular weight-melanoma associated antigen-specific monoclonal antibodies.

BACKGROUND: Acute leukemia with 11q23 aberrations is associated with a poor outcome with therapy. The lack of efficacy of conventional therapy has stimulated interest in developing novel strategies. Recent studies have shown that 11q23-positive acute leukemia cells express the high molecular weight-melanoma associated antigen (HMW-MAA). This tumor antigen represents a useful target to control growth of human melanoma tumors in patients and in severe combined immunodeficient (SCID) mice, utilizing antibody-based immunotherapy. This effect appears to be mediated by inhibition of the HMW-MAA function such as triggering of the focal adhesion kinase/proline-rich tyrosine kinase 2 (Pyk2) pathways. Therefore, in this study we tested whether HMW-MAA-specific monoclonal antibodies (mAb) could inhibit growth of 11q23-positive leukemia cells in SCID mice. METHODS: HMW-MAA-specific mAb were tested for their ability to inhibit the in vitro proliferation of an 11q23-positive acute myeloid leukemia (AML) cell line and blasts from four patients with 11q23 aberrations and their in vivo growth in subcutaneous and disseminated xenograft models. RESULTS: The HMW-MAA-specific mAb did not affect in vitro proliferation although they down-regulated phosphorylated (P) Pyk2 expression. Furthermore, the mAb enhanced the in vitro anti-proliferative effect of cytarabine. In vivo the mAb inhibited the growth of leukemic cells in a dose-dependent fashion. However, the difference did not reach statistical significance. No effect was detected on P-Pyk2 expression. Furthermore, HMW-MAA-specific mAb in combination with cytarabine did not improve tumor inhibition. Lastly, the combination of two mAb which recognize distinct HMW-MAA determinants had no detectable effect on survival in a disseminated xenograft model. CONCLUSIONS: HMW-MAA-specific mAb down-regulated P-Pyk2 expression and enhanced the anti-proliferative effect of cytarabine in vitro, but had no detectable effect on survival or growth of leukemia cells in vivo. Whether the HMW-MAA-specific mAb can be used as carriers of toxins or chemotherapeutic agents against 11q23-acute leukemia remains to be determined.