Molecular characterization and delineation of subtle deletions in de novo "balanced" chromosomal rearrangements.

To test the hypothesis that the phenotypic abnormalities seen in cases with apparently balanced chromosomal rearrangements are the result of the presence of cryptic deletions or duplications of chromosomal material near the breakpoints, we analyzed three cases with apparently balanced chromosomal rearrangements and phenotypic abnormalities. We characterized the breakpoints in these cases by using microsatellite analysis by polymerase chain reaction and fluorescence in situ hybridization analysis of yeast artificial chromosome clones selected from the breakpoint regions. Molecular characterization of the translocation breakpoint in patient 1 [46,XY,t(2;6)(p22.2;q23.1)] showed the presence of a 4- to 6-Mb cryptic deletion between markers D6S412 and D6S1705 near the 6q23.1 breakpoint. Molecular characterization of the proximal inversion 7q22.1 breakpoint in patient 2 [46,XY,inv(7)(q22.1q32.1)] revealed the presence of a 4-Mb cryptic deletion between D7S651 and D7S515 markers. No deletion or duplication of chromosomal material was found near the breakpoints in patient 3 [46,XX,t(2;6)(q33.1;p12.2)]. Our study suggests that a systematic molecular study of breakpoints should be carried out in cases with apparently balanced chromosomal rearrangements and phenotypic abnormalities, because cryptic deletions near the breakpoints may explain the phenotypic abnormalities in these cases.

Parental origin of De Novo chromosome 9 deletions in del(9p) syndrome.

Parental origin of de novo deletions in the short arm of chromosome 9 in patients with a clinical diagnosis of del(9p) syndrome was assessed in 13 patients using polymerase chain reaction (PCR) analysis of highly polymorphic dinucleotide repeat microsatellite markers located in the putative deleted region. The deletion was found to be of paternal origin in 9 cases and of maternal origin in the remaining 4 cases, suggesting that the molecular event resulting in the deletion occurs in both male and female gametogenesis and that genomic imprinting does not appear to play a role in the pathogenesis of del(9p) syndrome.

Chromosome abnormalities in B cell chronic lymphocytic leukemia and their clinical correlations.

Cytogenetic analysis was successfully performed on 31 of 40 patients with chronic B cell leukemia. Clonal abnormalities were seen in 16 patients using various culture methods. Fourteen of these had unstimulated cultures established of which 13 had the clonal abnormality. Trisomy 12 was observed in seven patients while a 14q32 translocation was present in four. Race, age, hemoglobin, WBC, percentage of lymphocytes and prolymphocytes in BM and PB, platelets, Smig, lymph node, spleen, liver, pattern of bone marrow infiltration, therapy free interval, and overall survival were all compared. Significant correlations between the presence of clonal abnormalities and prior therapy (p less than 0.005) and an increase in prolymphocytes in bone marrow (p = 0.05) and/or peripheral blood (p = 0.0014) were observed.

Prognostic implications of karyotype and morphology in patients with non-Hodgkin's lymphoma.

Clonal chromosome abnormalities were observed in 30 patients with non-Hodgkin's lymphoma; the type of lymphoma was characterized on the basis of the International Working Formulation. The 30 patients were classified into five groups according to the chromosome abnormality. There were 8 patients with t(14;18), 3 with t(8;14), 7 with a translocation to the long arm of chromosome 3 (a 3q+ chromosome), 5 with near-tetraploidy, and 7 with other abnormalities. Among the 8 patients with t(14;18), 5 had follicular small cleaved-cell lymphoma (FSC), I had follicular mixed cell lymphoma (FM), and 2 had diffuse large-cell lymphoma (DL); the diagnosis in these 2 patients was based on extranodal tissue. All 3 patients with t(8;14) had DL and B-cell markers. Except for 1 patient, all those with a 3q+ chromosome had DL; 4 of those who were tested had B-cell or pre-B-cell markers. Four of the 5 patients with near-tetraploidy had follicular mixed-cell lymphoma, and 2 of the 7 patients with other abnormalities had T-cell lymphoma. Thus, patients with a t(8;14), a 14q+ chromosome, or a 3q+ chromosome all tend to have diffuse large-cell lymphoma, usually of the non-cleaved type. On the other hand, our data suggest that patients with FSC generally have a t(14;18) whereas those with follicular and diffuse mixed small cleaved cells and large noncleaved cells have a different pattern with modal chromosome numbers in the tetraploid range. We added 17 previously reported patients to the 30 presented here and correlated the karyotype with survival. The 6 patients with near-tetraploidy had the longest median survival, 69 months, the 15 patients with t(14;18) had the next longest, 48 months. The 4 patients with t(8;14) had the shortest survival, 12 months, and the 9 with other abnormalities had the next shortest, 17 months. Intermediate survivals of 27 and 30 months were observed in patients with a 14q+ or a 3q+ chromosome, respectively. The median survival of these various categories differs and our data, thus, indicate that the karyotypic pattern of the malignant cell may be a significant independent prognostic feature influencing the survival of patients with non-Hodgkin's lymphoma.

Nonrandom chromosome abnormalities in angioimmunoblastic lymphadenopathy.

Cytogenetic and pathologic studies were performed on six patients with angioimmunoblastic lymphadenopathy (AILD). All six had diffuse lymphadenopathy; five had fever, four had weight loss, and four had a diffuse erythematous rash. All patients except one had a polyclonal elevation of immunoglobulin. All patients had diagnostic findings in lymph node (LN) and bone marrow (BM) biopsies. Two patients died of progressive AILD; one patient died after transformation of AILC to immunoblastic sarcoma (IBS); one patient died of gastrointestinal bleeding of unknown cause. The remaining two patients, who have achieved complete remission with intensive chemotherapy, are alive 20 and 8 mo after the diagnosis; one of these had AILD and the other, both AILD and IBS. Despite diagnostic BM biopsy findings, none of the patients had chromosome abnormalities in their BM cells. In studying LN cels of 5 patients, however, we found chromosome abnormalities in each; clonal abnormalities were detected in two, both clonal and nonclonal abnormalities in two, and only nonclonal single-cell abnormalities in one. An extra chromosome 3, seen in four patients, was clonal in two and nonclonal in the two others. Cells with +5, +15, +19, +21, +22 were seen in two patients. All patients had 50% or more normal dividing cells in their LN. The mosaicism of unrelated abnormal cells in their LN. The mosaicism of unrelated abnormal karyotypes that was seen in four patients suggests that this malignant tumor is not necessarily monoclonal in its early stages, but that one clone may be selected and predominate in the late stage. Because nonrandom acquired clonal chromosome abnormalities are a consistent feature of malignancies, our data suggest that AILD may be a malignant disease despite its original description as a benign proliferative process. Therefore, it may require aggressive chemotherapy.

Evidence for shared idiotypy expressed by the IgM, IgG, and IgA serum proteins of a patient with a complex multiple paraprotein disorder.

The results of a comparative idiotypic analysis of multiple Ig paraproteins isolated from the serum of an individual patient, Ca, with Sjögren's syndrome and Waldenström's macroglobulinemia are reported. At initial presentation, Ca serum was found to contain two major paraproteins, an IgMkappa and an IgGkappa, together with a small elevation in the level of IgA protein. The patient's clinical course was characterized by dramatic and opposing changes in the respective serum levels of the IgMkappa and IgGkappa paraproteins over an extended time period that coincided in part with received chemotherapy. Idiotypic antigenic analysis of the IgMkappa and IgGkappa paraproteins revealed that the two monotypic proteins shared identical idiotypic determinants. The Ca IgA serum fraction, specifically isolated by an immunoabsorbent and free of any IgG and IgM, was shown to possess idiotypic determinants identical to the IgG and IgM proteins. In extensive tests of specificity, the idiotypic determinants shared by Ca IgM, IgG, and IgA proteins were not present in large excesses of heterologous IgM and IgG, nor on Ig molecules contained in a large number of normal and myeloma sera.