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Biomedical subjects

Robert A Kyle

Publications and source records attributed to Robert A Kyle.

At least 19 recordsLinked to original sources
PubMed2007

A history of the kidney in plasma cell disorders.

BACKGROUND: The kidneys are commonly injured in plasma cell dyscrasias. METHODS: We reviewed the pertinent medical literature related to the historical development of clinical nephrology and diagnostic renal pathology; early case reports of patients with plasma cell disorders; and historical descriptions of multiple myeloma, amyloidosis, and the renal disorders that are associated with these conditions. RESULTS: Medieval uroscopists recognized proteinuria, and in 1827 Richard Bright first linked proteinuria to both dropsy (edema) and the autopsy finding of chronically diseased, scarred kidneys. In the 1840s, Henry Bence Jones and William Macintyre described a peculiar form of proteinuria in a middle-aged English grocer with fragile, tumor-riddled bones; this proteinuria became known as 'Bence Jones type'. It was initially believed that Bence Jones proteins were harmless to the kidney, but after 1899 (when myeloma cast nephropathy was recognized), investigators observed numerous renal injury patterns associated with plasma cell dyscrasias. Gross observations of 'waxy degeneration' or 'lardaceous change' in organs including the kidney yielded to the misnomer 'amyloid' in 1854, when iodine staining suggested to Rudolf Virchow that the strange material present in these conditions was a form of starch or cellulose. During the 20th century, biochemists and physicians carefully studied patients with myeloma, in order to better define the nature and structure of normal and pathological immunoglobulins. CONCLUSION: Historical understanding of the kidney in plasma cell disorders reflects developments in understanding of the anatomy and physiology of the kidneys in health and in disease.

Amyloidosis↗
PubMed2006

Gene-expression profiling of Waldenstrom macroglobulinemia reveals a phenotype more similar to chronic lymphocytic leukemia than multiple myeloma.

Waldenström macroglobulinemia (WM) is a B-cell malignancy characterized by the ability of the B-cell clone to differentiate into plasma cells. Although the clinical syndrome and the pathologic characteristics are well defined, little is known about its biology and controversy still exists regarding its cell of origin. In this gene-expression study, we compared the transcription profiles of WM with those of other malignant B cells including (chronic lymphocytic leukemia [CLL] and multiple myeloma [MM]) as well as normal cells (peripheral-blood B cells and bone marrow plasma cells). We found that WM has a homogenous gene expression regardless of 6q deletion status and clusters with CLL and normal B cells on unsupervised clustering with very similar expression profiles. Only a small gene set has expression profiles unique to WM compared to CLL and MM. The most significantly up-regulated gene is IL6 and the most significantly associated pathway for this set of genes is MAPK signaling. Thus, IL6 and its downstream signaling may be of biologic importance in WM. Further elucidation of the role of IL-6 in WM is warranted as this may offer a potential therapeutic avenue.

Antigens, CD↗
PubMed2006

Immunoglobulin free light chains and solitary plasmacytoma of bone.

An abnormal serum immunoglobulin free light chain (FLC) ratio at diagnosis may identify risk of progression to myeloma in patients with solitary bone plasmacytoma (SBP). In the cohort of 116 patients, 43 have progressed to myeloma, with a median time to progression of 1.8 years. The FLC ratio was determined in all 116 patients on serum collected at time of diagnosis and was abnormal in 54 patients (47%). An abnormal FLC ratio was associated with a higher risk of progression to myeloma (P = .039). The risk of progression at 5 years was 44% in patients with an abnormal serum FLC ratio at diagnosis compared with 26% in those with a normal FLC ratio. One to 2 years following diagnosis, a persistent serum M protein level of 5 g/L (0.5 g/dL) or higher was an additional risk factor for progression. A risk stratification model was constructed using the 2 variables of FLC ratio and M protein level: patients with a normal FLC ratio at baseline and M protein level less than 5 g/L (0.5 g/dL) at 1 to 2 years following diagnosis (low risk, n = 31); with either risk factor abnormal (intermediate risk, n = 26); and with both an abnormal FLC ratio and M protein level of 5 g/L (0.5 g/dL) or higher (high risk, n = 18). The corresponding progression rates at 5 years were significantly different in the low, intermediate, and high groups: 13%, 26%, and 62%, respectively (P < .001).

Adult↗
PubMed2006

Complete response in multiple myeloma: clinical trial E9486, an Eastern Cooperative Oncology Group study not involving stem cell transplantation.

BACKGROUND: The importance of obtaining a complete response (CR) in multiple myeloma (MM) treated with chemotherapy is unclear. METHODS: The Eastern Cooperative Oncology Group evaluated 653 previously untreated patients with active MM randomized to vincristine, carmustine (BCNU), melphalan, cyclophosphamide, and prednisone (VBMCP), to VBMCP and recombinant interferon alfa-2 (INFalpha-2), or to VBMCP and high-dose cyclophosphamide. RESULTS: Objective response was achieved in 420 (67%) of the 628 eligible patients, and 85 (14%) achieved a CR. Patients receiving VBMCP and recombinant INFalpha-2 had a significantly higher CR (18%) than those receiving VBMCP alone (10%) (P = .02). The CR rate for VBMCP and high-dose cyclophosphamide was 12%. Median duration of survival was 3.5 years for all eligible patients, and the estimated 5-year survival rate was 31%. The median duration of survival from the date of objective response was 5.1 years for those who achieved a CR and 3.3 years for those with a partial response (P < .0001). The median postresponse survival was 6.6 years in the 21 patients in CR with nonclonal disease and 4.4 years in the 11 patients in CR who had persistent clonal disease. All patients with negative immunofixation results and nonclonal plasma cells in whom polymerase chain reaction was performed had a positive result (presence of tumor DNA). CONCLUSION: Patients in whom a CR was achieved had a longer survival than those who had a partial response.

Adult↗
PubMed2006

Prevalence of monoclonal gammopathy of undetermined significance.

BACKGROUND: The prevalence of monoclonal gammopathy of undetermined significance (MGUS), a premalignant plasma-cell disorder, among persons 50 years of age or older has not been accurately determined. We used sensitive laboratory techniques to ascertain the prevalence of MGUS in a large population in a well-defined geographic area. METHODS: We identified all living residents of Olmsted County, Minnesota, as of January 1, 1995. We obtained serum that remained after the performance of routine clinical tests at Mayo Clinic or asked subjects for whom such serum was unavailable to provide a sample. Agarose-gel electrophoresis was performed on all serum samples, and any serum sample with a discrete band of monoclonal protein or thought to have a localized band was subjected to immunofixation. RESULTS: Serum samples were obtained from 21,463 of the 28,038 enumerated residents 50 years of age or older (76.6 percent). MGUS was identified in 694 (3.2 percent) of these persons. Age-adjusted rates were higher in men than in women (4.0 percent vs. 2.7 percent, P<0.001). The prevalence of MGUS was 5.3 percent among persons 70 years of age or older and 7.5 percent among those 85 years of age or older. The concentration of monoclonal immunoglobulin was less than 1.0 g per deciliter in 63.5 percent and at least 2.0 g per deciliter in only 4.5 percent of 694 persons. The concentration of uninvolved immunoglobulins was reduced in 27.7 percent of 447 persons tested, and 21.5 percent of 79 tested had a monoclonal urinary light chain. CONCLUSIONS: Among residents of Olmsted County, Minnesota, MGUS was found in 3.2 percent of persons 50 years of age or older and 5.3 percent of persons 70 years of age or older.

Age Distribution↗
PubMed2006

Cofactor-containing antibodies: crystal structure of the original yellow antibody.

Antibodies are generally thought to be a class of proteins that function without the use of cofactors. However, it is not widely appreciated that antibodies are believed to be the major carrier protein in human circulation for the important riboflavin cofactor that is involved in a host of biological phenomena. A further link between riboflavin and antibodies was discovered 30 years ago when a bright-yellow antibody, IgG(GAR), was purified from a patient with multiple myeloma who had turned yellow during the course of her disease. It was subsequently shown that the yellow color of this antibody was due to riboflavin binding. However, it was not known how and where riboflavin was bound to this antibody. We now report the crystal structure of this historically important IgG(GAR) Fab at 3.0-A resolution. The riboflavin is located in the antigen-combining site with its isoalloxazine ring stacked between the parallel aromatic moieties of TyrH33, PheH58, and TyrH100A. Together with additional hydrogen bonds, these interactions reveal the structural basis for high-affinity riboflavin binding. The ligand specificity of IgG(GAR) is compared with another riboflavin-binding antibody, IgG(DOT), which was purified from a second patient with multiple myeloma. The crystal structure of IgG(GAR) provides a starting point for attempts to understand the physiological relevance and chemical functions of cofactor-containing antibodies.

Antibodies, Monoclonal↗
PubMed2006

Standard chemotherapy compared with high-dose chemoradiotherapy for multiple myeloma: final results of phase III US Intergroup Trial S9321.

PURPOSE: Results of a prospective randomized trial conducted by the Intergroupe Francais du Myélome (IFM 90) indicated that autologous hematopoietic cell-supported high-dose therapy (HDT) effected higher complete response rates and extended progression-free survival (PFS) and overall survival (OS) compared with standard-dose therapies (SDT) for patients with multiple myeloma (MM). PATIENTS AND METHODS: In 1993, three North American cooperative groups launched a prospective randomized trial (S9321) comparing HDT (melphalan [MEL] 140 mg/m2 plus total-body irradiation 12 Gy) with SDT using the vincristine, carmustine, MEL, cyclophosphamide, and prednisone regimen. Responders on both arms (> or = 75%) were randomly assigned to interferon (IFN) or no maintenance treatment. RESULTS: With a median follow-up time of 76 months, no differences were observed in response rates between the two study arms (HDT, n = 261 patients; SDT, n = 255 patients). Similarly, PFS and OS durations did not differ between the HDT and SDT arms, with 7-year estimates of PFS of 17% and 16%, respectively, and OS of 37% and 42%, respectively. Of 242 patients achieving at least 75% tumor reduction, no difference was observed in PFS or OS among the 121 patients randomly assigned to IFN and the 121 patients randomly assigned to no maintenance therapy. Among 157 patients relapsing on SDT, 87 received a salvage autotransplantation; their median survival time of 30 months was only slightly better than the survival time of the remaining patients who were managed with further SDT (23 months; P = .13). CONCLUSION: The HDT and SDT regimens used in S9321 yielded comparable response rates and PFS and OS durations. IFN maintenance therapy did not benefit patients who achieved > or = 75% tumor reduction on either arm.

Adult↗
PubMed2006

Absolute values of immunoglobulin free light chains are prognostic in patients with primary systemic amyloidosis undergoing peripheral blood stem cell transplantation.

The immunoglobulin free light chain (FLC) is the precursor protein of amyloid in primary systemic amyloidosis (AL). Historically, the ability to monitor the amyloid protein precursor protein has been crude. We evaluated the utility of the FLC assay in a retrospective analysis of patients with AL undergoing peripheral blood stem cell transplantation (PBSCT). Ninety-three such patients had serial FLC measurements performed. The prognostic effects of the initial concentration and the extent of reduction of monoclonal FLC on survival were studied. There was a significantly higher risk of death in patients with higher baseline FLC (hazard ratio 2.6, P < .04). Baseline FLC correlated with serum cardiac troponin levels, and higher FLC levels were associated with more organs involved by amyloid, suggesting that high FLC levels may be associated with more advanced disease. The percent FLC reduction did not predict for survival, but the absolute level of FLC achieved after therapy did. Normalization of FLC level after PBSCT predicted for both organ response and complete hematologic response. Achievement of FLC response was a better predictor of survival than achievement of complete hematologic response or normalization of the FLC ratio. FLC measurements both before and after PBSCT are important predictors of patient outcome.

Adult↗
PubMed2006

Natural history and therapy of 66 patients with mixed cryoglobulinemia.

Cryoglobulinemia, a relatively uncommon disorder, is classified into types I, II, and III, with type II consisting of a monoclonal immunoglobulin possessing activity toward a polyclonal component. Many disease associations and therapies have been described but clinical trials are few, and the natural history, causes, therapy, and pathways of cryoglobulinemia require further investigation. Here, we describe the symptoms, comorbidities, treatments, and response of 66 patients with type II cryoglobulinemia by examining the records of all patients evaluated at Mayo Clinic, Rochester, Minnesota, between 3/2/1994 and 11/27/2000, using our prospective dysproteinemia database. Symptoms varied greatly among patients and during the disease course. Most common were purpura (55% of patients), renal disease (26%), edema (24%), neuropathy (18%), and arthralgia (21%). Renal disease required the most aggressive intervention. Laboratory findings did not correlate with disease manifestations or severity. Only age was a significant predictor of mortality. Ten patients had cryoglobulinemia without an identified comorbidity. Thirty-three patients had viral hepatitis alone, 6 had a lymphoproliferative disorder alone, and 5 had a rheumatologic disease alone. Ten patients had a combination of disorders, such that hepatitis C was identified in a total of 40 patients, lymphoproliferative disorders in 16, and rheumatologic disease in 8. Twenty-two different treatments were administered. Corticosteroids were the most common treatment, followed by interferon with or without ribavirin. Type II cryoglobulinemia is a nonfatal disease most frequently associated with hepatitis C. Treatment is generally directed at the underlying condition. Not all patients require treatment, and many can be followed and treated symptomatically.

Adrenal Cortex Hormones↗
PubMed2006

6q deletion discriminates Waldenström macroglobulinemia from IgM monoclonal gammopathy of undetermined significance.

IgM monoclonal gammopathy of undetermined significance (IgM MGUS) and Waldenström macroglobulinemia (WM) are sometimes clinically difficult to distinguish. In our previous study, deletion of the long arm of chromosome 6 (6q) was found in about half of WM patients. To further clarify the area of minimal deletion at 6q (6q-) and to address the issue of whether 6q- occurs in IgM MGUS, 12 IgM MGUS and 38 WM patients were studied by fluorescence in situ hybridization using probes targeting different chromosomal segments of 6q. No 6q deletions were found in IgM MGUS samples. Of 38 successfully studied WM patients, 21 (55%) showed a deletion of 6q. The area of minimal deletion was between 6q23 and 6q24.3, but the deletion usually encompassed a large fragment of the 6q arm. These results indicate that 6q- can distinguish WM from IgM MGUS and is likely to be a secondary event.

Aged↗
PubMed2006

Treatment of multiple myeloma: an emphasis on new developments.

Not all patients who fulfill the minimal criteria for diagnosis of multiple myeloma should be treated. If doubt exists about beginning therapy, one should wait and re-evaluate the patient in 2 or 3 months. There is no evidence that early treatment of multiple myeloma is advantageous. All patients should be considered possible candidates for an autologous stem cell transplantation. If they are deemed to be eligible, they should be treated for 3 to 4 months with therapy that does not damage the hematopoietic stem cells. Currently, most physicians use thalidomide plus dexamethasone or dexamethasone alone for induction. Vincristine, doxorubicin (Adriamycin), and dexamethasone (VAD) have been used in the past. Autologous stem cell transplantation prolongs disease-free survival and overall survival. The treatment-related mortality rate is 1% to 2%. Melphalan, 200 mg/m2, is the most widely used preparative regimen. Although allogeneic transplantation is attractive, the mortality rate (about 20%) is too high to recommend conventional allogeneic transplantation. Non-myeloablative transplantation is currently under investigation. If the patient is not a candidate for autologous stem cell transplantation, therapy with melphalan and prednisone is a good choice. Patients with relapsed or refractory disease may be treated with dexamethasone, thalidomide and dexamethasone, bortezomib (Velcade, PS-341), or lenalidomide (Revlimid, not yet approved by the Food and Drug Administration).

Angiogenesis Inhibitors↗
PubMed2006

Natural history of thromboembolism in AL amyloidosis.

To determine the natural history of thromboembolism in patients with biopsy-proven AL amyloidosis, medical records of 2,132 patients evaluated at Mayo Clinic between 1975 and 2000 were reviewed. Forty patients (21 male) were found to have objectively documented thromboembolism. The median age was 65 years. Four patients had a monoclonal gammopathy of undetermined significance, 20 had an unspecified plasma cell proliferative disorder, 11 had multiple myeloma, and 1 had Waldenström macroglobulinemia. Twelve patients had cardiac amyloid, and 20 had renal amyloid. Neither the extent of the amyloid nor the type of monoclonal protein was predictive of the development of thromboembolic events. Thromboembolism preceded the diagnosis of AL amyloidosis in 11 patients, occurred at the time of diagnosis or within 1 month after diagnosis in 11 patients, and occurred 1 month or more after diagnosis in 18 patients. Twenty-nine patients (73%) had venous thrombosis and 11 (28%) had arterial thrombosis. Eight patients (20%) died within 1 month after the thrombotic event, and 18 (45%) died within 1 year. The development of thrombosis in patients with AL amyloidosis appears to predict significant mortality within the first month and year after the event.

Aged↗
PubMed2006

Prognostic model for disease-specific and overall mortality in newly diagnosed symptomatic patients with Waldenstrom macroglobulinaemia.

We sought to define prognostic factors for survival in Waldenstrom macroglobulinaemia (WM). Of 585 patients diagnosed with WM and seen at Mayo Clinic between 1960 and 2001, 337 symptomatic patients met the inclusion criteria and were analysed for overall and disease-specific survival. The median survival from the time of diagnosis was 6.4 years. The median disease-specific survival was 11.2 years. Univariate analysis for overall survival identified the following adverse prognostic factors: age >65 years (P < 0.001), organomegaly (P < 0.001), elevated beta2-microglobulin (<0.001), anaemia (Hb < 10.0 g/dl) (P = 0.01), leucopenia (<4.0 x 10(9)/l) (P = 0.03), thrombocytopenia (<150 x 10(9)/l) (P = 0.01), serum albumin <40 g/l (P = 0.001), and quantitative IgM < 0.4 g/l (P = 0.04). On multivariate analysis, age >65 years and organomegaly were associated with poor prognosis. A prognostic model was built based on these two variables. Patients at high risk (1-2 risk factors, median survival 4.2 years) experienced worse survival than patients at low risk (0 risk factors, median survival 10.6 years), P < 0.001. The prognostic model was validated in 204 patients who were not included in the analysis cohort. Beta2-microglobulin > or =4 mg/l was associated with a threefold increase in the risk of death when added to the prognostic model. We describe a simple prognostic model for overall survival for newly diagnosed patients with WM.

Adult↗
PubMed2006

Monoclonal gammopathy of undetermined significance.

Significant advances have been made in our understanding of the natural history, pathogenesis, mechanisms of progression and prognosis of monoclonal gammopathy of undetermined significance (MGUS). Although the overall incidence of MGUS progression is 1 per year, it is now possible to more accurately predict the risk of progression based on a new risk-stratification model. However, it is still hard to design chemopreventive trials given that the absolute risk of progression per year is low, even in the high-risk group. Therefore, further improvements in estimating the risk of progression are needed. Roughly 50% of MGUS may originate from primary translocation events at the heavy-chain immunoglobulin locus at chromosome 14q32. In most of the remaining MGUS patients, the initiating event is associated with genomic instability that results in hyperdiploidy of certain odd numbered chromosomes. Cytogenetically distinct subtypes of MGUS may carry significant differences in the risk of progression to malignancy. New markers, such as measures of bone marrow angiogenesis and circulating plasma cells may be additional prognostic factors. A better understanding of the mechanisms underlying the transition of normal plasma cells to the MGUS phenotype, and the transition of MGUS to myeloma or related malignancy, will help identify new risk factors for progression and new targets for chemopreventive interventions.

Aged↗
PubMed2006

Response to rituximab in patients with type II cryoglobulinemia.

Type II cryoglobulinemia (CG) is a heterogeneous, generally indolent disorder caused by a monoclonal antibody with activity against polyclonal antibodies and is commonly associated with hepatitis C, lymphoproliferative disorders (LPDs), or autoimmune diseases. It can lead to substantial morbidity, including renal failure, cutaneous ulcers, or neuropathy. Medical records were reviewed for 8 patients with previously treated symptomatic CG who were part of a prospectively held dysproteinemia database. Patients subsequently received 14 total courses of rituximab treatment (standard infusion, 375 mg/m2 for 4 or 8 doses) between February 1999 and March 2005. One patient had essential CG, and 1 had Gaucher disease with hypersplenism. Six patients had an LPD, and 4 of them had concomitant disorders (2 with hepatitis C and 2 with Sjogren syndrome). Treatment indications included purpura, LPD, cutaneous ulcers, and renal failure. Clinical improvement was evaluated by improved cryocrit, total complement, C4, and rheumatoid factor. Six patients had some clinical improvement. Cutaneous manifestations were the most responsive; renal disease and lymphoma were more refractory. Laboratory values showed improvement after 7 of 12 available treatment courses. No adverse reactions were noted. Overall, rituximab appears to be a safe and effective therapy.

Antibodies, Monoclonal↗
PubMed2006

Elimination of the need for urine studies in the screening algorithm for monoclonal gammopathies by using serum immunofixation and free light chain assays.

OBJECTIVE: To determine the relative diagnostic contribution of urine assays as part of the screening algorithm for monoclonal gammopathies. PATIENTS AND METHODS: We identified 428 patients with a monoclonal gammopathy and monoclonal urinary protein at initial diagnosis of plasma cell dyscrasia who had also undergone serum immunofixation and serum free light chain quantitation within 30 days of diagnosis. The laboratory results for serum protein electrophoresis, serum immunofixation, serum free light chain, urine protein electrophoresis, and urine immunofixation were reviewed. RESULTS: The patients had diagnoses of multiple myeloma, primary amyloid, monoclonal gammopathy of undetermined significance, smoldering multiple myeloma, solitary plasmacytomas, and other less frequently detected monoclonal gammopathies. All 428 had a monoclonal urine protein, 85.7% had an abnormal serum free light chain kappa/lambda ratio, 80.8% had an abnormal serum protein electrophoresis, and 93.5% had an abnormal serum immunofixation result. All 3 serum assays were normal in only 2 patients, 1 of whom had monoclonal gammopathy of undetermined significance (idiopathic Bence Jones proteinuria) and 1 whose urine sample contained an intact monoclonal immunoglobulin but whose serum and subsequent urine samples showed no evidence of a monoclonal gammopathy. CONCLUSION: Discontinuation of urine studies and reliance on a diagnostic algorithm using only serum studies (protein electrophoresis, immunofixation, and free light chain quantitation) missed 2 (0.5%) of the 428 monoclonal gammopathies with urinary monoclonal proteins, and these 2 cases required no medical intervention.

Algorithms↗