Polymerase chain reaction in the diagnosis of onychomycosis: a large, single-institute study.

BACKGROUND: Tests commonly used in the diagnosis of onychomycosis include potassium hydroxide (KOH) preparation, histopathological examination with periodic acid-Schiff stain (PAS) and culture. These tests are either time-consuming or require specially trained personnel. A recently developed polymerase chain reaction (PCR) assay has the potential to provide a quick, inexpensive, operator-independent diagnosis of onychomycosis. OBJECTIVE: To determine the range of fungal species detected by the PCR technique and to compare this technique with KOH, PAS and culture on patient specimens. METHODS: A total of 176 dermatophytic and nondermatophytic fungal culture isolates were tested by PCR. Five hundred and fifty nail specimens from 550 patients with suspected onychomycosis were split and tested concurrently with PCR, PAS, KOH and culture. RESULTS: PCR was positive in 65 out of 66 dermatophyte culture isolates and negative in all 110 nondermatophyte and yeast isolates. Overall, PAS, PCR, KOH and culture were positive in 54%, 37%, 40% and 22% of specimens, respectively. Fifty-two per cent were positive for KOH and PCR. CONCLUSION: PCR is a specific, relatively sensitive test for onychomycosis. When used in conjunction with KOH, PCR can produce positivity rates similar to those with PAS alone.

Clonal determination by the fragile X (FMR1) and phosphoglycerate kinase (PGK) genes in hematological malignancies.

The polymerase chain reaction (PCR) clonality assay based on the principle of random X chromosome methylation in females provides a potentially important tool in both cancer research and diagnostics. This assay, however, has not been compared to the standard Southern blot assay and is limited by the rate of heterozygosity of the X-linked phosphoglycerate kinase (PGK) and androgen receptor genes, the only two genes yet described with which this technique may be used. Using 46 marrow and blood specimens from females with and without hematological malignancies, the PCR and Southern blot methods of clonality were compared. In addition, a new technique based on the highly polymorphic fragile X (FMR1) locus was examined. The rate of heterozygosity was 25% for the PGK gene and 45% for the FMR1 gene. In the PCR assay, 7 of 8 and 11 of 14 normal control specimens showed a polyclonal methylation pattern in the PGK and FMR1 genes, respectively. Of the malignant specimens, 17 of 17 and 17 of 18 showed a monoclonal methylation pattern in the PGK and FMR1 genes, respectively. The Southern blot and PCR assay gave similar results with regards to the PGK gene. It is concluded that the PCR and Southern blot clonality assays are comparable with regards to the PGK gene and that both the PGK and FMR1 genes may be reliably used in the determination of clonality. The methods, however, are limited by the skewed methylation patterns seen in hematological specimens in a significant number of normal females.

Presence of cell lineage-specific hypomethylated sites in the major breakpoint cluster region.

To examine the role of DNA methylation in breakpoint location of chromosomal translocation, HpaII sites in and flanking the M-bcr on chromosome 22 were mapped in DNA from blood granulocytes and lymphocytes, bone marrow cells, thymic tissue, and spermatozoa from normal individuals. Allelic HpaII sites were identified clustered in a 600-base pair genomic area of the M-bcr. Bone marrow cells and blood granulocyte DNA showed identical allelic patterns. Thymic tissue and blood lymphocytes showed identical allelic patterns distinct from bone marrow cells and blood granulocytes. Spermatozoa showed a third methylation pattern. In all individuals, the HpaII sites were present within the BamHI/BglII fragment of the M-bcr, the same area associated with high breakpoint frequency in chronic myelogenous leukemia (CML). Three of 15 patients with chronic phase CML showed fully methylated rearranged BglII/BglII M-bcr restriction fragments not seen in normal bone marrow cells. These methylation patterns of the M-bcr may be important in CML breakpoint location and may be a marker for tissue differentiation.

Direct detection of the Philadelphia chromosome in CD20-positive lymphocytes in chronic myeloid leukemia by tri-color immunophenotyping/FISH.

Six patients with previously diagnosed chronic myelogenous leukemia (CML) were studied by a tri-color immunophenotyping/FISH method for direct determination of the Philadelphia (Ph) chromosome in B and T lymphocytes. Two patients had involvement of CD20-positive lymphocytes. CD3-positive lymphocytes in all patients were negative for the Ph chromosome.

Late-developing Philadelphia chromosomes in a case of T-cell acute lymphoblastic leukemia.

A child with T-cell acute lymphoblastic leukemia (ALL) is presented who at relapse acquired two Philadelphia chromosomes (Ph). Molecular studies at relapse revealed a rearrangement of the major breakpoint cluster region (M-bcr) on chromosome 22. No rearrangements of the immunoglobulin heavy chain or T-cell beta receptor gene loci were demonstrated. This case supports the hypothesis that leukemogenesis in Ph-positive malignancies is a multi-step process, the first step of which may not necessarily involve acquisition of the Ph.

Methylation status of the major breakpoint cluster region in Philadelphia chromosome negative leukemias.

It has been shown that a 600 bp long cluster of cell lineage specific hypomethylated sites in the major breakpoint cluster region (M-bcr) on chromosome 22 exists in hematopoietic cells. To determine possible relationships between methylation patterns within the M-bcr and the stage of hematopoietic cell development, the M-bcr methylation status of 39 patients with leukemia and lymphoma and two patients with myelodysplastic syndrome with non-rearranged M-bcrs was examined by BgIII-HpaII digestion. In the myeloid malignancies, the presence of a hypermethylated 4.8 kb BgIII-BgIII M-bcr allele was directly proportional to the combined myeloblast and promyelocyte percentage of the specimen, whereas the presence of a 2.5 kb BgIII-HpaII allele was directly proportional to the combined percentage of monocytic cells and neutrophils. All five acute monoblastic leukemias showed a methylation pattern that closely resembled neutrophils. All of thirteen surface immunoglobulin positive B-cell malignancies showed a distinct methylation pattern consisting of three or more BgIII-HpaII restriction fragments of 2.5 kb or less in length. The B-cell precursor leukemias showed heterogeneous M-bcr methylation patterns, with four of seven showing a B-cell pattern and three showing a hypermethylated pattern with 4.8, 3.1/3.0 and/or 2.5 kb BgIII-HpaII M-bcr alleles. It is concluded that the M-bcr methylation status is related to the maturation of the neutrophil series; the surface immunoglobulin positive B-cell malignancies are characterized by a distinct, extreme hypomethylation pattern of the M-bcr; and the B-cell precursor malignancies appear to have a heterogeneous M-bcr methylation pattern.

Fluorescence in situ hybridization (FISH) detection of trisomy 8 in myeloid cells in chronic myeloid leukemia (CML): a study of archival blood and bone marrow smears.

Patients in accelerated phase or blast crisis of chronic myeloid leukemia (CML) frequently develop clonal cytogenetic abnormalities in addition to the Philadelphia chromosome. Using a DNA probe directed to the centromere of chromosome 8, we performed fluorescence in situ hybridization (FISH) on archival Wright-stained blood and bone marrow smears of seven patients with CML and with a known +8 clone by metaphase cytogenetics to determine the distribution of +8 in interphase cells. All slides had been stored at ambient temperature for 12-26 months. The bone marrow aspirate smears of 21 non-leukemic patients served as controls. Trisomy 8 was demonstrated in all myeloid cell lines including the neutrophils, basophils, eosinophils, monocytes, and erythroid precursors, but not in the lymphocytes. The extra chromosome 8 was present in mature segmented granulocytes as well as more immature precursors. The percentage of +8 cells was highest in specimens from patients with CML in myeloid blast crisis (mean 64%), followed by those in accelerated phase (mean 39%). Three specimens from patients in morphologic chronic phase showed the lowest percentage of +8 cells (mean 13%). One patient was studied twice and showed a substantial expansion of +8 cells with progression from accelerated phase to myeloid blast crisis. Compared to metaphase cytogenetics, the proportion of +8 cells detected by FISH was often lower. We conclude that the acquisition of trisomy 8 in CML occurs in a pluripotent myeloid stem cell apparently incapable of expressing mature lymphoid phenotype, and that morphologic progression of disease is generally associated with an expansion of the +8 component.

Demonstration of clonality in neutrophils using FISH in a case of chronic neutrophilic leukemia.

A patient previously diagnosed with chronic neutrophilic leukemia (CNL) was studied using fluorescent in situ hybridization (FISH) to determine clonality of neutrophils. By cytogenetic studies the patient's blood and bone marrow had an 11q14 deletion and were negative for the Philadelphia (Ph) chromosome. FISH was performed on peripheral blood smears using probes for the bcr/abl translocation and a probe for 11q23 (MLL). The patient's white blood cells were negative for the bcr/abl translocation; neutrophils and eosinophils, but not lymphocytes, were monosomic for the 11q23 probe indicating a clonal population within the neutrophil population.

Transformation of chronic lymphocytic leukemia to small non-cleaved cell lymphoma: a cytogenetic, immunological, and molecular study.

A patient with chronic lymphocytic leukemia (CLL) transforming into a small non-cleaved cell lymphoma (SNCL) with the occurrence of a t(8;22) is described. The SNCL and the CLL were both found to have a germline lambda light chain gene configuration and the same heavy chain and kappa light chain gene rearrangements. The SNCL was CD10 (CALLA) negative and appeared to be CD5 negative. It is concluded that the SNCL is derived from the CLL and that activation of the c-myc oncogene may have played a role in this transformation.

Acute leukemia and the transient myeloproliferative disorder associated with Down syndrome: morphologic, immunophenotypic and cytogenetic manifestations.

Individuals with Down syndrome have an increased incidence of leukemia compared to the general population. In addition, Down syndrome children may acquire a myeloproliferation that resembles acute leukemia that undergoes a spontaneous, durable remission. To clarify the relationship between these two disorders, the morphologic, immunophenotypic and cytogenetic characteristics of 28 patients with Down syndrome and the morphologic manifestations of acute leukemia were examined. Three cytomorphological groups were discerned. The first two groups consisted of five patients with acute lymphoblastic leukemia (group I) and three patients with acute myeloid leukemia (group II). These leukemias resembled those of non-Down individuals. The third and largest group (group III) consisted of 20 cases of acute myeloid leukemia that showed prominent megakaryocytic and/or erythroid differentiation and occurred in children under 6 years of age. The blasts in this group were non-reactive for myeloperoxidase or non-specific esterase and expressed CD7, CD34 and CD36 with variable expression of CD61, CD13 and CD33. Four patients in this group had an acquired trisomy 8. Four group III leukemias underwent a durable, spontaneous remission within 2 months of diagnosis. There were no morphologic differences between those leukemias in this group that progressed and those that remitted; however, all remissions occurred in newborns. It is concluded that Down syndrome children acquire a characteristic acute myeloid leukemia that has prominent megakaryocytic and/or erythroid differentiation and an unusual immunophenotype. This group of leukemias may undergo a durable, spontaneous remission in the newborn period.

Intracellular bacteria in blood smears in patients with central venous catheters.

The presence of intracellular bacteria in blood smears is usually associated with overwhelming sepsis and an ominous prognosis. Recently, the hematology laboratory at our institution documented this finding in a group of mostly asymptomatic patients. We studied seven adult patients from a tertiary care university hospital in whom intracellular bacteria were found incidentally on routine manual differential cell counts of 100 white blood cells during a 12-month period. A retrospective review of the clinical and laboratory data was performed. All seven patients were immunosuppressed and had central venous catheters in place. The blood samples positive for intracellular bacteria were all catheter derived. Six patients were asymptomatic at the time of bacteria detection, but they had blood cultures that were positive for coagulase-negative Staphylococcus; five of these patients became symptomatic 1 to 14 days after bacteria detection. Bacteremia persisted in five of these six patients until the eventual removal of the catheters. The one symptomatic patient had Pseudomonas aeruginosa bacteremia and died shortly after admission. The finding of intracellular bacteria in routine differential blood cell counts from a central venous catheter blood specimen most likely indicates active infection. We recommend that central venous catheters be removed in such patients, even if the patient is asymptomatic.

Absence of detectable chromosomal and molecular abnormalities in monozygotic twins discordant for the Wiedemann-Beckwith syndrome.

Monozygotic twins discordant for the Wiedemann-Beckwith syndrome (WBS) were studied by cytogenetic and molecular methods to determine if a genetic lesion could be detected in the affected child. Probes known to be localized on the short arm of chromosome 11 and a low copy-repetitive probe were used. No genetic lesions could be ascertained in normal or affected tissue obtained from the WBS twin.

Chronic myelogenous leukemia: molecular diagnostic considerations.

Chronic myelogenous leukemia (CML) is associated in 95% of cases with the Philadelphia chromosome (Ph1) by cytogenetic analysis. This acquired karyotypic abnormality is the product of a balanced translocation between the c-abl oncogene on chromosome 9 and the breakpoint cluster region (BCR) gene on chromosome 22. The resulting BCR/c-abl hybrid gene is actively transcribed and is considered essential in the pathogenesis of this disease. Southern blot- and polymerase chain reaction (PCR)-based tests for the detection of this rearrangement have been introduced over the last decade. These molecular tests are useful adjuncts to cytogenetic analysis in CML and may provide useful clinical information in certain instances.

Detection of c-erbB-2 activation in paraffin-embedded tissue by immunohistochemistry.

Commercially available monoclonal antibodies were tested for their ability to detect increased levels of c-erbB-2 protein in formalin-fixed, paraffin-embedded breast carcinomas. Of five antibodies studied, four (TAB-250, CB11, 3B5, and N3/D10) showed strong cytoplasmic membrane reactivity in 23% (11 of 47) of routinely processed tumors, although interpretation of the immunoreactivity with 3B5 and N3/D10 occasionally was difficult due to cytoplasmic granular staining. Since the c-erbB-2 oncogene is activated by DNA amplification and overexpression of mRNA and protein, the same tumors were analyzed for c-erbB-2 activation by other techniques. c-erbB-2 activation in these 11 tumors was confirmed by immunohistochemistry of frozen tissue (nine of nine tumors), in situ hybridization (nine of 11 tumors), and Southern blot analysis (five of eight tumors). In some of these tumors the failure to demonstrate c-erbB-2 DNA amplification may be due to the small percentage of malignant cells. One additional tumor showed probable c-erbB-2 protein overproduction based on strong immunoreactivity with two antibodies (TAB-250 and CB11), although no definite activation could be demonstrated by additional techniques. Three other tumors (6%) showed equivocal c-erbB-2 protein overproduction based on weak immunoreactivity only with TAB-250, although unequivocal activation could not be demonstrated by additional techniques. The 32 carcinomas (68%) that showed no significant immunoreactivity with any antibodies in routinely processed tissue also showed no detectable c-erbB-2 activation by additional techniques. We conclude that TAB-250 and CB11 are reliable antibodies for detecting c-erbB-2 protein overproduction in routinely processed tissue. TAB-250 also weakly stains a few tumors showing no definite c-erbB-2 activation by other techniques. Two additional antibodies (3B5 and N3/D10) detect c-erbB-2 protein overproduction in paraffin-embedded tissue, but are more difficult to interpret. A fifth antibody, TA-1, is an excellent reagent for use on frozen tissue, but prolonged formalin fixation may impair recognition of its antigenic epitope.

Acute lymphoblastic leukemia in a case of essential thrombocythemia.

Essential thrombocythemia is a myeloproliferative disorder that infrequently evolves into acute leukemia. Leukemic transformation is frequently preceded by therapy with alkylating agents or radioactive phosphorus (32P), and is virtually always myeloid in nature. In this report, the authors describe a case of acute lymphoblastic leukemia arising in a patient with long-standing essential thrombocythemia.

Morphologic and quantitative changes in blood and marrow cells following growth factor therapy.

Sequential blood and bone marrow specimens from 53 patients receiving recombinant granulocyte (G-CSF) or granulocyte macrophage colony stimulating growth factor (GM-CSF) for neutropenia were evaluated. The blood findings were marked by a neutrophilia with a prominent left shift, increased azurophilic granulation, Döhle bodies, and an elevated leukocyte alkaline phosphatase; circulating myeloblasts were observed but did not exceed 2% of the leukocytes. Nuclear segmentation abnormalities consisting of hyposegmentation, hypersegmentation, and ring nuclei were noted but were not a prominent finding. A leukoerythroblastosis was present in 54% of patients. No consistent effect on cell lines other than neutrophils was found. A monocytosis was present in 12 patients, a transient lymphocytosis in 2 and an eosinophilia in 1. No effect was evident on basophils. The morphologic changes in the neutrophils in the bone marrow specimens were most pronounced in the early period of growth factor therapy with a relative neutrophil hyperplasia with a marked increase in promyelocytes and myelocytes. With increasing duration of therapy, the myeloid to erythroid ratio normalized and the percentage of promyelocytes decreased while myelocytes and band neutrophils increased. Thirteen patients had no response to growth factor. The nonresponding patients were clinically diverse; all bone marrow biopsy specimens in this group were virtually acellular. No differences were noted between G-CSF and GM-CSF.

Aberrant DNA methylation of genomic regions translocated in myeloid malignancies.

The mechanism of aberrant genetic recombinatorial events in neoplasia is vaguely understood. One hypothesis is that aberrant DNA methylation may in some way predispose genomic regions to recombination. Using the t(9;22) of chronic myeloid leukemia (CML) and the t(15;17) of acute promyelocytic leukemia (APL) as models, our laboratory and others have gathered data supporting this hypothesis. These data are reviewed.

A novel approach to clonality analysis. Alterations in genomic methylation of Epstein-Barr virus transformed lymphocytes.

We have studied eight different Epstein-Barr virus transformed cell lines (EBV-LCL) with respect to genomic methylation at a single locus, M-bcr (the major breakpoint cluster region of chronic myelogenous leukemia). Restriction digests with the methylation sensitive enzyme, Hpall, illustrated marked differences in M-bcr methylation patterns between the various cell lines. Some of the cell lines displayed prominent allelic heterogeneity: within each of these samples there were numerous different M-bcr/Hpall allelic fragments on Southern analysis. Other cell lines displayed allelic predominance: within each of these samples a limited number of M-bcr/Hpall allelic fragments predominated. Analysis of Immunoglobulin JH rearrangements demonstrated a close correlation between clonal complexity (i.e. the number of rearranged JH fragments) and allelic heterogeneity of M-bcr methylation (i.e. the number of M-bcr/Hpall fragments). We conclude that analysis of genomic methylation in the M-bcr locus may offer a novel approach to clonality determination in EBV transformed lymphocytes.

Chronic lymphoproliferative disorders: classification and diagnosis.

The chronic lymphoproliferative disorders are morphologically, immunologically and clinically heterogeneous. Common features of these processes include T, B or natural killer cell immunophenotypes and terminal deoxy-nucleotidyl transferase negativity. The B cell lymphocytic disorders include B-chronic lymphocytic leukaemia, B cell prolymphocytic leukaemia, chronic lymphocytic leukaemia-prolymphocytic leukaemia, non-Hodgkin's lymphoma (including mantle cell lymphoma) in leukaemic phase, hairy cell leukaemia and splenic lymphoma with villous lymphocytes. The T cell chronic lymphoproliferative disorders include prolymphocytic leukaemia, adult T cell leukaemia-lymphoma, large granulated lymphocyte leukaemia and Sézary syndrome. Occasionally, a lymphocytic proliferation is encountered that does not satisfy the morphological or immunophenotypical criteria for any of the above categories. These processes are best left unclassified.