Safety and tolerability of cladribine tablets in multiple sclerosis: the CLARITY (CLAdRIbine Tablets treating multiple sclerosis orallY) study.

BACKGROUND: Cladribine is a synthetic deoxyadenosine analogue in development as an oral multiple sclerosis (MS) therapy. OBJECTIVE: To report in detail the safety findings from the 96-week, phase III, double-blind CLARITY study, which evaluated treatment with cladribine tablets in relapsing-remitting MS. METHODS: A total of 1,326 patients were randomized 1:1:1 to two short-course regimens of cladribine tablets (3.5 or 5.25 mg/kg cumulative dose over 96 weeks) or placebo. Safety assessments included monitoring for adverse events (AEs), routine physical and neurologic examinations and frequent laboratory parameter assessments. RESULTS: Of the randomized patients, 88.6% completed treatment with cladribine tablets versus 86.3% with placebo. Lymphopenia was the most commonly reported AE in patients treated with cladribine tablets and was anticipated based on the mechanism of action. The incidence of infections was 48.3% with cladribine tablets and 42.5% with placebo, with 99.1% and 99.0% rated mild-to-moderate by investigators. Herpes zoster infections developed in 20 (2.3%) cladribine-treated patients; all cases were dermatomal. There were no herpes zoster infections in the placebo group. Nine (1.0%) patients experienced events related to uterine leiomyomas in the cladribine tablets groups versus one (0.2%) with placebo. Three isolated cases of malignancy were reported in cladribine-treated patients during the study; a fourth was reported during post-study surveillance. A pre-malignant cervical carcinoma in situ was also reported. The incidence of malignancies during the study did not exceed the expected rate in a population standardized for country, gender and age. CONCLUSION: The safety and tolerability profile observed in the CLARITY study together with the reported efficacy support the potential for cladribine tablets as an MS therapy.

Utility of topiramate for the treatment of patients with chronic migraine in the presence or absence of acute medication overuse.

Chronic migraine has been linked to the excessive use of acute headache medications. Medication overuse (MO) is commonly considered the most significant risk factor for the progression of migraine from an episodic to a chronic condition. Managing MO is a challenge. Discontinuation of the acute medication can result in withdrawal headache, nausea, vomiting and sleep disturbances. This review summarizes the results from two similarly designed, randomized, placebo-controlled, multicentre studies of chronic migraine conducted in the USA and European Union. Both studies demonstrate the efficacy and safety of the migraine preventive medication, topiramate, for the treatment of chronic migraine in patient populations both with and without MO. These studies may have important implications for the future of chronic migraine management, suggesting that detoxification prior to initiating prophylactic therapy may not be required in all patients if MO is present.

Multiple sclerosis characteristics in African American patients in the New York State Multiple Sclerosis Consortium.

The objective of this study was to determine the clinical characteristics of multiple sclerosis (MS) in African American (AA) patients in the New York State Multiple Sclerosis Consortium (NYSMSC) patient registry. The NYSMSC is a group of 18 MS centers throughout New York State organized to prospectively assess clinical characteristics of MS patients. AAs comprise 6% (329) of the total NYSMSC registrants (5602). Demographics, disease course, therapy, and socioeconomic status were compared in AA registrants versus nonAfrican Americans (NAA). There was an increased female preponderance and a significantly younger age at diagnosis in the AA group. AA patients were more likely to have greater disability with increased disease duration. No differences were seen in types of MS and use of disease modifying therapies. Our findings suggest a racial influence in MS. Further genetic studies that consider race differences are warranted to elucidate mechanisms of disease susceptibility.

Syngeneic central nervous system transplantation of genetically transduced mature, adult astrocytes.

Advances in the development of highly infectious, replication-deficient recombinant retroviruses provide an efficient means of stable transfer of gene expression. Coupled with ex vivo transduction, surrogate cell populations can be readily implanted into the brain, thus serving as vehicles for delivering selected gene products into the central nervous system (CNS). Here we report that rat astrocytes can be routinely and safely isolated from brain tissue of a living donor by use of short-term gelatin sponge implants. The mature, nontransformed astrocytes were easily expanded, maintained in long-term tissue cultures and were efficiently transduced with an amphotropic retrovirus harboring a heterologous, fused transgene. In vitro retroviral infection rendered the nontransformed cells essentially 100% viable after exposure. The level of efficiency of infection (30-50% effective genome integration of provirus and expression of transgene in target cell populations) and minimal cell toxicity obviated the need to harvest large numbers of target cells. Cultured transduced astrocytes were resilient and exhibited select peptide expression for up to 1 year. Subsequently, transduced astrocytes were used in a series of experiments in which cells were transplanted intracerebrally in syngeneic animals. Post-implantation, astrocytes seeded locally and either insinuated into the surrounding parenchyma in situ or exhibited a variable degree of migration, depending on the anatomic source of astrocytes and the targeted brain implantation site. Transduced astrocytes remained viable in excess of 8 months post-transplantation and exhibited sustained transgenic peptide expression of green fluorescent protein/neomycin phosphotransferase in vivo. The sequential isolation and culture of nontransformed, mature, adult astrocytes and recombinant retrovirus-mediated transduction in vitro followed by brain reimplantation represents a safe and effective means for transferring genetic expression to the CNS. This study lays the foundation for exploring the utility of using a human autologous transplantation system as a potential gene delivery approach to treat neurological disorders. Prepared and utilized in this manner, autologous astrocytes may serve as a vehicle to deliver gene therapy to the CNS.

Orbital involvement as the initial manifestation of sarcoidosis: magnetic resonance imaging findings.

A 74-year-old man had diplopia, painful right ophthalmoplegia, proptosis, conjunctival injection, and facial skin lesions. Magnetic resonance imaging (MRI) revealed infiltration of the right intraorbital adipose tissue. Lesions were mixed low- and high-signal on T2-weighted images and enhanced on fat-suppressed T1-weighted postcontrast images. A skin biopsy revealed numerous noncaseating granulomas consistent with sarcoidosis. Treatment with corticosteroids and chlorambucil led to a full clinical recovery. Sarcoidosis should be considered in the evaluation of orbital pseudotumor in elderly patients, even if no systemic manifestations of sarcoidosis are present.

A profile of multiple sclerosis: the New York State Multiple Sclerosis Consortium.

We have obtained a current profile of multiple sclerosis York State through a centralized patient registry and standardized data collection instrument associated with the New York State Multiple Sclerosis Consortium of 12 MS centers located throughout the state. Data from the first 3019 patients with clinically definite MS revealed a clear relationship between MS disease type, duration of disease, and severity of physical disability. Patients with relapsing disease had disease durations approximately half as long as those with progressive forms of the disease (means approximately 6 years versus 11 years). The majority of patients with relapsing disease had Expanded Disability Status Scale (EDSS) scores of 4.0 or less (self-sustained, fully ambulatory), whereas the majority of patients with progressive disease types had EDSS scores of 6.0 or greater (at least unilateral assist for walking). These findings emphasize the importance of early intervention in patients with relapsing disease to slow or prevent the accumulation of physical disability associated with progressive types of disease. Progressive disease was associated with lack of full-time employment and being disabled before the age of 60 years. Patients with relapsing disease were more likely to be employed and have private forms of insurance, whereas patients with progressive types of disease were more likely to have government-supported insurance to cover medical expenses.

Hormonal effects on glioblastoma multiforme in the nude rat model.

OBJECT: The authors studied the effect of gender and hormonal status on survival in nude rats implanted with human glioblastoma multiforme (GBM) cell lines. METHODS: Nude rats received intracerebral implants of either wild-type U87MG cells or U87MG cells transfected with the gene for endothelin-1 (U87/ET-1). In the initial study, survival was compared in males and females for each of the two cell lines. The six second-phase study groups were composed of: 1) males; 2) females; 3) ovariectomized females; 4) sham ovariectomized females; 5) ovariectomized rats given 10 microg/day estradiol benzoate for 21 days; and 6) ovariectomized rats given 20 mg/kg/day progesterone for 21 days. All rats in the second phase were implanted with U87/ET-1 cells. Animals were killed when they exhibited initial signs of neurological deterioration. Female nude rats survived longer than male rats implanted with either U87 or U87/ET-1 cells. In the second phase, ovariectomized, male, and progesterone-treated rats died at approximately 19 days, whereas the female, sham-treated, and estrogen-treated animals died 23 to 25 days after tumor cell implantation. CONCLUSIONS: The authors demonstrate that female nude rats implanted with human GBM cells have a survival advantage over male rats and that estrogen provides the advantage.

Leber's hereditary optic neuropathy mitochondrial DNA mutations in familial multiple sclerosis.

Leber's hereditary optic neuropathy (LHON) can be difficult to distinguish from optic neuritis due to multiple sclerosis (MS). For several decades an association of LHON and MS has been suspected, and within the past 7 years the LHON nucleotide (nt)-3460 and nt-11778 mtDNA mutations have been identified in several patients with MS-like phenotypes. To further study this association, we tested 42 index patients with clinically definite, familial MS for the LHON mtDNA mutations at nt-3460, nt-11778, and nt-14484. No patients had a pathogenic LHON mtDNA mutation; however, two MS patients with unilateral optic neuritis harbored the nt-15257 mtDNA polymorphism that was reported originally as a pathogenic LHON mutation. Several investigators have shown evidence that the nt-15257 mtDNA mutation is not primarily pathogenic. Therefore, we conclude that pathogenic LHON mtDNA mutations are absent or rare in unselected patients with familial, clinically definite MS (95% confidence intervals for each of the negative mutations 0-7.0%).

Intratumoral infusion of topotecan prolongs survival in the nude rat intracranial U87 human glioma model.

Topotecan is a topoisomerase (topo) I inhibitor with promising activity in preclinical studies. We hypothesized that low-dose intratumoral delivery of topotecan would be highly effective for gliomas. Human glioma cell lines (U87, U138 and U373) displayed different sensitivities to topotecan (IC50 range: 0.037 microM to 0.280 microM) in cell culture. The most resistant of the glioma cell lines (U87) was implanted stereotactically into the brains of nude rats. Twelve days later, at which time tumor diameter measured 2 to 2.5 mm, animals were randomized to three groups: group I, intratumoral topotecan infused via osmotic pump (n = 12); group II, intratumoral saline infusion (n = 7); and group III, no treatment (n = 10). Animals were sacrificed when signs of deterioration developed, or at 60 days. Animals in group I had a mean survival time (MST) of > 55 days (range = 40-60); whereas, those in groups II and III had MST of 26.1 (range = 21-31) and 26.5 (range = 20-30) days, respectively. The differences in survival between group I and each of the other groups were statistically significant (p < 0.0001; Logrank Mantel-Cox). None of the animals that survived 60 days had histological evidence of residual tumor at sacrifice. Measurement of topotecan levels in normal brain revealed cytotoxic concentrations up to 4.5 mm from the site of infusion. This study demonstrates that intratumoral topotecan delivered via an osmotic pump prolongs survival in the U87 human glioma model.

An experimental model of human leukemic meningitis in the nude rat.

An experimental animal model of meningeal leukemia was developed in the nude rat, rnu/rnu, using the human-derived acute lymphoblastic leukemia cell line HPB-ALL. Anesthetized rats were placed in a modified stereotaxic frame and then injected intrathecally, at the level of the cisterna magna, with human leukemic cells. Cerebrospinal fluid and tissue samples from brain, spinal cord, heart, liver, kidney, spleen, bone marrow, and cervical lymph nodes were subjected to histopathologic examination and molecular genetic screening by clonotype primer-directed polymerase chain reaction (CPD-PCR). Ninety-three percent of animals (n = 14) developed signs of meningeal irritation leading to death 30 to 63 days postinjection (median, 36.0 days, mean, 38.7); death occurred between 30 and 39 days in 77% of all animals. Leukemic cells progressively infiltrated the pericerebellar and pericerebral subarachnoid space and infiltrated the Virchow-Robin (perivascular) space. The infiltrating meningeal leukemia closely resembled the pathologic presentation in the human condition. By CPD-PCR, leukemic cells were first detected in cerebrospinal fluid (CSF) on day 4 postinjection, were variably present over the ensuing 17 days, and were consistently detected after day 21. At terminal stages, CPD-PCR tissue surveys showed leukemic DNA in all brains and spinal cords and rarely in cervical lymph nodes, but leukemic DNA was not detected in any other tissue screened. Leukemic meningitis was reliably produced with a predictable survival time. Intrathecal administration of leukemic cells was an efficient means of transmitting leukemic meningitis and it compartmentalized the disease to the central nervous system (CNS), eliminating potential complications of systemic illness. The use of human-derived cell lines may render this model more relevant to the development of future therapeutic strategies to treat leukemia and lymphoma that invade the CNS.

Retinoic acid-induced modulation of IL-2 mRNA production and IL-2 receptor expression on T cells.

BACKGROUND: Retinoic acid (RA) has important immune-modulating effects on both T and B cell function. Our laboratory has shown that RA can enhance in vitro polyclonal B cell immunoglobulin (Ig) response. Investigating cytokines known to affect B cell differentiation, we have recently shown that IL-6 production is augmented by RA. In the present study we have examined the immune modulating effects of RA on IL-2 mRNA, another important cytokine for B cell immunoglobulin production, the expression of IL-2 receptors on T cells, and the RA nuclear receptors. METHODS: Purified T cells were obtained from adenoidal tissues, and incubated with RA (10(-7) M) or DMSO solvent/media control for 0, 6-8, and 24 h. Total mRNA was extracted from T cells, and using RT-PCR, changes in the production of IL-2 and RA receptors (RAR)-alpha,beta,gamma mRNA were determined. The effects of RA on IL-2-alpha receptor expression was determined by flow cytometry on T cells. CONCLUSION: These studies suggest that RA can augment IL-2 mRNA production by T cells with a possible paracrine effect on IL-2R-alpha expression. These changes appear to be mediated by RAR-alpha. Thus, IL-2 may be another important cytokine modulated by RA in the immune response.

Correlation of endothelin-1 and transforming growth factor beta 1 with malignancy and vascularity in human gliomas.

Because the prominent neovascularization characteristic of high grade primary brain tumors is composed mostly of vascular smooth muscle cells (VSMC), we studied the expression of the potent smooth muscle mitogen endothelin-1 (ET-1) and one of its secretagogues, transforming growth factor beta 1 (TGF-beta 1) in a series of astrocytic tumors. TGF-beta 1 is also of interest due to its known activity as an angiogenic factor. Using immunohistochemical methods, we examined 30 surgical cases: 10 glioblastoma multiforme, 10 anaplastic astrocytomas, and 10 low-grade astrocytomas. Using a monoclonal antibody to TGF-beta 1 and a polyclonal antibody to ET-1, we detected both growth factors in all cases of glioblastoma examined. In cases of anaplastic astrocytoma, 4 tumors were positive for both factors; 2 contained only ET-1; 2 contained only TGF-beta 1; and 2 exhibited no tumor cell immunoreactivity for either factor. In low-grade astrocytoma, 4 of 10 tumors showed weak ET-1 immunoreactivity; 2 of those contained TGF-beta 1 immunopositive tumor astrocytes: 6 tumors were negative for both factors. In all tumors that expressed both factors, serial sections showed that regions of ET-1 immunopositivity also tended to be positive for TGF-beta 1. Endothelial cells within all tumors were positive for ET-1. ET-1 and TGF-beta 1 are present in human astrocytomas and their expression correlates with tumor vascularity and malignancy. These results suggest roles for both ET-1 and TGF-beta 1 in the growth and progressive angiogenesis of the human glioma.

Pleiotropic expression of heterologous cytokine/receptor genes in HTLV-1 associated diseases: candidate TRS for chimeric gene therapy.

DNA motifs that encode for specific transcriptional regulatory sequences (TRS) when engineered adjacent to the structural protein coding domain of a suicide enzyme can provide cell-lineage specific protein expression. The disparate up-regulation of several genes in adult T-cell leukemia (ATL) versus HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP), seropositive carriers (SPC) and uninfected normals may reflect events at the molecular level related to leukemogenesis or to processes maintaining the heme-oncologic phenotype. Further, the genetic transduction of cytokine and receptor genes uniquely associated with ATL may provide targets for the development of leukemia-specific gene therapies aimed at exploiting differences in the production of certain growth factors and growth factor receptors. Comparisons of the transcriptional and translational levels of interleukin-2 receptor alpha chain (IL-2R alpha), transforming growth factor-beta 1 (TGF-beta 1) and intracellular adhesion molecule-1 (ICAM-1) in ATL, HAM/TSP, and SPC and in several control populations revealed selectively up-regulated expression in ATL. We evaluated the feasibility of using lymphoid-specific TRS to activate herpes simplex virus thymidine kinase (HSVtk) to achieve selective cytotoxicity in leukemias expressing terminal deoxynucleotidyl transferase (TdT). Selective and efficient leukemic cell killing was produced and suggests that similar chimeric gene constructs containing TRS elements for IL-2R alpha, TGF-beta 1, or ICAM-1 may prove useful in designing gene therapies to treat ATL.

Development of a severe combined immunodeficiency (SCID) mouse model consisting of highly disseminated human B-cell leukemia/lymphoma, cure of the tumors by systemic administration of immunotoxin, and development/application of a clonotype-specific polymerase chain reaction-based assay.

A new severe combined immunodeficiency (SCID) mouse model consisting of highly disseminated human B-cell leukemia/lymphoma was developed by i.v. inoculation of BALL-1a, an in vivo adapted malignant B-cell line. A 100% transplantability was achieved in nonpreconditioned SCID mice using various BALL-1a doses between 2.5 x 10(4) and 6 x 10(6) cells. Hind-leg paralysis preceded the death of the mice. Utility of the developed tumor model for the therapeutic studies was investigated by i.v. administration of an anti-B-cell monoclonal antibody SN7 (IgG1) and its conjugate with deglycosylated ricin A chain (dgRA). The therapy was initiated 2, 4, or 6 days after tumor inoculation using 4 x 24 microg of SN7-dgRA or 4 x 20 microg of SN7; the total dose (96 microg) of SN7-dgRA corresponded to 14% of the LD50 dose. SN7-dgRA showed a strong antitumor efficacy in all groups of treated mice. All of the day-2 group mice (n = 7) and six (66.7%) of the day-4 group mice (n = 9) survived healthily for as long as followed (240 days), whereas four (57.1%) of the day-6 group mice (n = 7) survived healthily for as long as followed (200 days). Unconjugated SN7 showed a significant antitumor efficacy but was less effective than SN7-dgRA. A PCR-based assay specific for the clonogenic BALL-1a tumor was developed and applied to determine tumors in various organs of BALL-1a-bearing SCID mice. The assay was highly sensitive in screening for trace quantities of residual tumors in various organs of SCID mice, and it could detect 1 malignant cell/2.5 x 10(5) tissue cells. The PCR-based assay was shown to be much more powerful than the conventional histological analysis in detecting residual tumors. Furthermore, we could estimate quantities of the detected tumors by the PCR-based assay. It is remarkable to find that all examined organs of some of the SN7-dgRA-treated mice were tumor-free as determined by the clonotype-specific PCR-based assay. The present results show the usefulness of the newly developed SCID mouse model, SN7-dgRA, and the clonotype-specific PCR-based molecular assay for the study of therapy of human B-cell leukemia/lymphoma.

Polymerase chain reaction assays for the detection of cytomegalovirus in organ and bone marrow transplant recipients.

Cytomegalovirus (CMV) infection is ubiquitous and results in a wide spectrum of clinical manifestations ranging from asymptomatic infection to severe life threatening disease. Infection in normal children and adults usually causes no symptoms but in the immunocompromised host, CMV may result in severe opportunistic infections with high morbidity and mortality. Historically, virus detection was dependent on culture of the virus or on a centrifugation culture system referred to as a shell vial assay. The shell vial assay frequently lacked sensitivity and was unable to detect infection in its early phase. Also, as with culture assays, the results were affected by antiviral therapy. The CMV antigenemia assay was developed to provide more rapid results and has gained wide usage. This assay is limited to detection of the virus in white blood cells and is more sensitive than culture or the shell vial assay. Application of the polymerase chain reaction (PCR) to these problems has resulted in the development of assays for CMV which are more sensitive than previously available methods. This method employs liquid hybridization with 32P labeled probes and gel retardation analysis for detection of amplified DNA specific for each virus. A comparison of the detection of CMV by an antigenemia assay or the PCR method in the leukocytes of renal transplant patients revealed that the PCR assay detects cytomegalovirus earlier and more consistently than the antigenemia assay. Finally, the application of a fluorescent dye detection system and image analysis of the acrylamide gel with a laser scanner provides additional sensitivity to the detection of cytomegalovirus, as well as avoiding the use of radioactivity, making the assay more adaptable to the clinical laboratory.

HTLV-associated diseases: human retroviral infection and cutaneous T-cell lymphomas.

An array of neurologic, oncologic, and autoimmune disorders are associated with infection with the human pathogenic retroviruses human T-cell leukemia virus types I and II (HTLV-I, II), as well as the human immunodeficiency viruses (HIV). The cutaneous T-cell lymphomas, mycosis fungoides (MF) and its hematogenous variant Sezary Syndrome (SS), share similar clinical and pathological features to HTLV-I-associated adult T-cell leukemia (ATL) and speculation of a retroviral link to MF and SS, especially in areas non-endemic for ATL, has lead to an intensified search for HTLV- and HIV-like agents in these diseases. To further explore a potential role for human retroviruses in MF and SS, skin biopsy-derived or peripheral blood mononuclear cell-derived DNA from 17 patients (MF, n = 7; erythrodermic MF (EMF), n = 5; SS, n = 5) from the North Eastern United States were screened using gene amplification by PCR and a liquid hybridization detection assay. Previously published primers and probes for HTLV-I (LTR, gag, pol, env, and pX), and our own primers and probes for HTLV-I (gag, pol, and env), HTLV-II (pol and env) and HIV-I (gag and pol) were employed. Serum antibodies to HTLV-I were negative in all but one EMF patient. The single HTLV-I seropositive patient carrying a diagnosis of EMF generated positive amplified signals for all of the eight HTLV-I regions tested. Ultimately, this individual evolved to exhibit clinical manifestations indistinguishable from ATL. The other 16 patients were negative for all 12 HTLV and HIV retroviral regions. Our findings suggest that none of the known prototypic human retroviruses are associated with seronegative MF and SS. The uniformly positive results for HTLV-I in the seropositive patient suggests that this patient initially presented with a smoldering form of ATL and illustrates the difficulty that sometimes may be encountered in the differential diagnosis of MF, SS, and ATL based solely on clinical and histopathological criteria.

Novel compound tetra-, dinucleotide microsatellite polymorphism in the tumor necrosis factor/lymphotoxin locus.

A polymorphic (TGCG)n, tetranucleotide repeat was discovered juxtaposed to the (GT)n dinucleotide repeat that comprises the tumor necrosis factor a microsatellite (TNF) located telomeric to the tumor necrosis factor/lymphotoxin gene cluster. The degree of complexity of this compound tetra-,dinucleotide microsatellite consists of 16 potential alleles of combined length ranging from 24 to 54 bp. The pattern of frequencies of individual alleles belonging to the compound TNFa microsatellite was established from 52 healthy volunteers and was found to be highly heterogeneous. The data diverges significantly from previously published statistics that recognized only a simple variable dinucleotide tandem repeat. The newly recognized compound tetra-, dinucleotide TNFa microsatellite polymorphism establishes a more accurate genetic basis to explore potential linkage with disease susceptibility genes located within this region of the class III major histocompatibility complex. In addition, variable tumor necrosis factor and lymphotoxin production may reflect the more complex polymorphic nature of this microsatellite region. Finally, compound microsatellites probably exist elsewhere, throughout the human genome. Recognition of their presence may have a considerable impact on the validity of past and future microsatellite-based genetic analyses.

The "Dreadful Visitation": public health and public awareness in seventeenth-century London.

The decision was made in Britain three centuries ago that an educated populace was best able to deal with a public health crisis of staggering proportions--outbreaks of bubonic and pneumonic plague. As early as 1603, the printing press was enlisted to educate the public about urgent health issues. This education took several forms. The City of London, with the tacit permission of the Crown, printed bills of mortality that reported who was dying of what in London, detailed by parish, for the years in the seventeenth century when plague deaths were reported. New books about plague prevention and cures were published; older works were reprinted. The resulting wealth of data gave impetus to the evolution of the new field of epidemiological demographics, founded by John Graunt and Sir William Petty. Publishing in the plague years also established a model for informing the general populace that is not without parallel in today's "information society."

Detection of group C rotavirus in infants with extrahepatic biliary atresia.

The purpose of this retrospective study was to examine liver tissue from patients with cholestatic disease for the presence of group C rotavirus RNA. The reverse transcriptase-polymerase chain reaction (PCR) for genes 5 and 6 was used, and the PCR products were subjected to liquid hybridization with a 32P-labeled probe. A second amplification with nested primers was also used. Samples from 32 subjects (20 with biliary atresia or choledochal cyst and 12 controls) were tested. Ten of 20 biliary atresia patients were positive for group C rotavirus RNA; no controls were positive (P < .003). Three of the positive patients were positive for both genes 5 and 6. Six of the 10 had > 1 sample that was positive. These data suggest a possible relationship between group C rotavirus and extrahepatic biliary atresia in the 10 patients in whom virus RNA was detected.

Clonal evolution in B-lineage acute lymphoblastic leukemia by contemporaneous VH-VH gene replacements and VH-DJH gene rearrangements.

B-cell acute lymphoblastic leukemia (B-ALL), more frequently than any other B-lineage neoplasm, exhibits oligoclonal Ig heavy chain (IgH) gene rearrangement in 15% to 43% of all cases studied. To study the molecular processes that promote multiple IgH rearrangements, a comprehensive sequence analysis of a B-ALL case was performed in which seven clonal IgH gene rearrangements were identified. The genetic profiles suggested that a single leukemic progenitor clone evolved into several subclones through dual processes of variable (VH) to preexisting diversity-joining (DJH) gene segment rearrangement and VH to VH gene replacement. Predominant IgH-V usage and the uniquely rearranged clonotype-specific VHDJH region gene sequences were identified using a novel DNA-based gene amplification strategy. Polymerase chain reaction (PCR) was directed by an IgH-J generic primer and a complement of family-specific IgH-V primers that defined the major B-cell IgH-V gene usage. Clonality of rearranged VHDJH bands was substantiated by high resolution denaturant gel electrophoretic analysis. Sequence patterns of the amplified VHDJH fragments segregated into two groups defined by common DJH sequences. Partial N region homology at the VHD junction as well as shared DJH sequences firmly established VH to VHDJH gene replacement as a mechanism generating clonal evolution in one group. In the second subset, oligoclonality was propagated by independent VH gene rearrangements to a common DJH precursor. The contributions of all clonal Ig-VHDJH repertoires for each group was approximately 50% and reflected a symmetric distribution of leukemic subclones generated by either process. Thus, oligoclonal rearrangements evolved by two independent, yet seemingly contemporaneous molecular genetic mechanisms. All seven clones displayed nonfunctional Ig-VHDJH recombinations. These observations may have relevance to the recombinatorial opportunities available during normal B-cell maturation.