PubMed Health⌕ Search

Biomedical subjects

S Abhyankar

Publications and source records attributed to S Abhyankar.

At least 19 recordsLinked to original sources
PubMed2003

Immunological and clinical effects of post-transplant G-CSF versus placebo in T-cell replete allogeneic blood transplant patients: results from a randomized double-blind study.

BACKGROUND: Immunological and clinical effects of post-transplant growth factor administration have not been well studied. This report describes the outcome and immune functions of a total of 50 HLA-matched related donor allogeneic blood stem-cell transplantation patients who received post-transplant G-CSF (10 microg/kg) or placebo. METHODS: Immune status, including number of lymphocyte subsets and their functions, and serum immunoglobulin levels and clinical status--including GvHD, rate of relapse, event-free survival, and overall survival--were determined in the patients enrolled in this study. RESULTS: Twenty-eight patients survived 1 year after transplant, and 15 patients had available results to compare immune function by randomization assignment. At 12 months post-transplant, immune parameters in G-CSF versus placebo groups showed no statistically significant differences in number of circulating lymphocyte subsets CD3, CD4, CD8, CD19 and CD56 in the two groups. There was no significant (NS) difference in immunoglobulin IgG, IgA and IgM levels, NK or LAK cell-mediated cytotoxicity levels, and mitogen-induced proliferation between post-transplant G-CSF and placebo group. In addition, the analyses of immune parameters at earlier time-points on Days 28, 100, 180, and 270 revealed that, except for LAK cytotoxicity at Day 100, there was no differences between the two groups. Fourteen of 26 patients are alive in the G-CSF arm and nine of 24 in the placebo arm. Median follow-up of surviving patients is 43 months. Four year overall and event-free survival in the G-CSF and the placebo group were 53% and 35% (NS), and 44% and 36% (NS) respectively. Bacterial or fungal infections were the cause of six of 12 deaths in the G-CSF arm (all bacterial) and of four of 15 deaths in the placebo arm (two deaths from Aspergillus) (P=0.26). Two patients relapsed in the G-CSF arm and three in the placebo arm. Four year cumulative incidences of relapse were 8% versus 13% in G-CSF versus placebo arms, respectively, (NS). Chronic GvHD developed in 14 of 19 100-day survivors after G-CSF (11 extensive stage), and in 17 of 20 (14 extensive stage) in the placebo arm. The 4-year cumulative incidence of chronic GvHD was 56% [95% confidence interval (CI) 24-88%] after G-CSF and 71% (95% CI 48-94%) after placebo; this difference was not statistically significant (log rank P=0.41). CONCLUSION: In summary, there were no significant immunological or alterations in clinical benefit of post-transplant G-CSF administration in T-replete allotransplant recipients.

Adult↗
PubMed2001

Treatment of steroid-refractory acute graft-versus-host disease with anti-CD147 monoclonal antibody ABX-CBL.

ABX-CBL, an immunoglobulin M murine monoclonal antibody, recognizes CD147 and initiates cell killing through complement-mediated lysis. In a dose-finding trial, 27 patients with steroid-refractory acute graft-versus-host disease (GVHD) received ABX-CBL at 0.01 (presumed no effect dose), 0.1, 0.2, or 0.3 mg/kg per day, and an additional 32 patients were given ABX-CBL at 0.2 or 0.15 mg/kg per day. All patients had undergone allogeneic transplantation for malignant or nonmalignant disorders and received GVHD prophylaxis, generally with methotrexate- and cyclosporine-containing regimens. None responded to methylprednisolone, given for a minimum of 3 days. ABX-CBL was started 20 to 236 (median, 47) days after transplantation; it was given for 7 consecutive days and was followed by 2 infusions per week for 2 more weeks. Among 51 patients evaluable for efficacy, 26 (51%) responded, including 13 with complete responses (CR) and 13 with partial responses (PR). CR lasting 14 days or longer or PR lasting 7 days or longer occurred in 21 (41%; 8 CR, 13 PR) patients, including 19 of 43 (44%) patients who received 0.1 to 0.3 mg/kg ABX-CBL and 2 of 8 (25%) patients given 0.01 mg/kg per day. Myalgias at doses 0.2 mg/kg or greater were dose limiting and resolved without sequelae. Causes of death included organ failure, progressive GVHD, and infection. No death was attributed to ABX-CBL. At 6 months after the initiation of ABX-CBL therapy, 26 (44%) patients were surviving. These results are encouraging. Further studies on the use of ABX-CBL in the management of GVHD are warranted.

Acute Disease↗
PubMed2000

Evaluation of the half-life of intravenous human cytomegalovirus immune globulin in patients receiving partially mismatched related donor bone marrow transplantation.

STUDY OBJECTIVE: To evaluate the pharmacokinetics and use of intravenous human cytomegalovirus immune globulin (CytoGam) in allogeneic bone marrow transplantation (BMT). DESIGN: Prospective, nonrandomized, nonblinded, single-center study. SETTING: University teaching hospital. PATIENTS: Five consecutive patients with hematologic malignancies receiving partially mismatched related donor BMT with a uniform conditioning regimen including total body irradiation and chemotherapy. INTERVENTION: Serum immunoglobulin and cytomegalovirus (CMV) titers were measured before and 24 hours after the first CytoGam infusion on day -6 during the conditioning regimen. MEASUREMENTS AND MAIN RESULTS: These levels were measured every 5 days, and a second dose was administered when the CMV titer returned to 25-50% of the 24-hour level. The half-life of CytoGam was approximately 7 days. CONCLUSION: We believe this is the first report of CytoGam's half-life in allogeneic BMT. The information may prove vital in a future study in which the agent's potential beneficial effects can be maximized.

Adult↗
PubMed1997

Flow cytometric cell sorting combined with molecular chimerism analysis to detect minimal recurrent leukemia: good news and bad news.

Allogeneic BMT offers the possibility of cure for a variety of hematopoietic malignancies, but disease relapse remains a major cause of treatment failure. This report describes two cases in which flow cytometric cell sorting (FACS) and molecular chimerism analysis were combined to increase the sensitivity of minimal residual disease (MRD) detection. In the first case this approach was used to demonstrate that a suspicious phenotype was not recurrent leukemia, thus preventing the use of potentially toxic therapy. In the second case the recurrence of a leukemia which was undetectable by conventional analysis was confirmed. The potential benefits of combining these MRD detection methods are discussed.

Adolescent↗
PubMed1996

Partially mismatched related donor transplants as salvage therapy for patients with refractory leukemia who relapse post-BMT.

Patients who relapse post-ABMT are usually resistant to conventional therapy, and a potentially curative therapy with allogeneic BMT is limited due to availability of a matched donor. To assess whether such patients can be salvaged using partially mismatched related donors (PMRD), eight patients age 6-50 years old underwent PMRD-BMT. All patients ALL (n = 3) and AML (n = 5) were in relapse 7-31 months after first BMT. Donors (1-3 Ag mismatch) were selected from family members. Conditioning included TBI, etoposide, Ara-C and cytoxan (n = 3), or busulfan, thiotepa, and etoposide (n = 5). GVHD prophylaxis consisted of partial T cell depletion followed by systemic immunosuppression. All evaluable patients established sustained engraftment by day 18. Severe regimen-related toxicity was evident in the gastrointestinal and hepatic systems (6/8 and 4/8, respectively), the latter associated with poor outcome (P < 0.014). Acute but not chronic GVHD, grade > or = II occurred in 3/7 patients. Four of eight patients are disease-free, maintaining longer remission than following their first BMT (14 vs 9 months). In conclusion, our data shows that PMRD-BMT is a feasible option for patients who relapse post-BMT and use of such alloreactive grafts may be appropriate earlier in the disease course of high risk patients.

Adolescent↗
PubMed1994

T cell receptor (beta chain) transgenic mice have selective deficits in gamma delta T cell subpopulations.

TCR-beta (T cell receptor-beta chain) transgenic mice have altered lymphocyte development. TCR-beta transgenic mice are hyporesponsive to alloantigens in vivo and are deficient in gamma delta T cells. In order to begin a study of the relationship between a deficiency of alloreactive gamma delta cells and the defective function of in vivo alloantigen recognition, we analysed the gamma delta T cell development in TCR-beta mice. The presence of the TCR-V beta 8.2 chain transgene is associated with inhibition of gamma chain gene rearrangement. In order to determine how the presence of the TCR-beta transgene affects gamma delta T cell development, gamma delta T cells were studied in the skin, intestine and spleen. TCR-beta mice have dramatically reduced numbers of gamma delta T cells in the spleen and moderately reduced numbers of gamma delta T cells among intestinal intraepithelial lymphocytes. In contrast, these mice have normal numbers of gamma delta dendritic epidermal cells (DEC). These selective deficits could be due to the developmental regulation of transgene transcription during fetal life. We examined transcription of the TCR-beta transgene in the fetal thymus and found that the TCR-beta transgene is first transcribed at high levels on day 16 of fetal life, after DEC have already migrated from the thymus to the epidermis. Furthermore, mRNA from the transgene was detected in DEC, ruling out the formal possibility that DEC bear a gamma delta receptor only because they are incapable of expressing the transgene.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

SENCAR mouse skin tumors produced by promotion alone have A to G mutations in codon 61 of the c-rasHa gene.

SENCAR mice, developed by selective breeding for high susceptibility to skin carcinogenesis by initiation with 7,12-dimethylbenz[a]anthracene and promotion with 12-O-tetradecanoylphorbol-13-acetate (TPA), form squamous papillomas in approximately 20% of animals treated repeatedly with TPA, without chemical initiation. DNA from eight skin tumors produced by a TPA-only protocol and four cell lines derived from these tumors was amplified by polymerase chain reaction and analyzed by discriminative oligonucleotide hybridization using oligomers specific for various c-rasHa gene codon 61 sequences. Five tumors and three cell lines had CAA (wild-type) to CGA mutations. In addition, one tumor had a CAA to CTA mutation, for a total of six of eight tumors having an activating mutation at this codon. Two tumors and one cell line had no codon 61 mutations detectable by this method. Since tumors derived from promotion-only protocols presumably originated from constitutively initiated cells, we examined tumor-free skins of untreated newborn and eight-month-old retired breeders and of 78-88-week-old SENCAR mice of both sexes, which were treated with TPA for 10 weeks starting at age 16-28 weeks and were untreated thereafter. Only the wild-type c-rasHa gene codon 61 sequence was seen, suggesting that the constitutively initiated cell population, if present, is below the limit of detection by this method.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1993

Interleukin-1 is a critical effector molecule during cytokine dysregulation in graft versus host disease to minor histocompatibility antigens.

Cytokines are believed to cause a number of inflammatory diseases. We have investigated the role of 3 inflammatory cytokines, IL-1, IL-2, and TNF alpha, during graft-versus-host disease (GVHD), a paradigm disease of cytokine dysregulation in vivo. Measuring cytokine mRNA transcripts with a quantitative polymerase chain reaction technique, we demonstrate that IL-1 transcript levels are increased several hundred-fold in GVHD target organs, whereas TNF alpha transcripts increase only 4- to 6-fold. Kinetic studies during the first month after transplant unexpectedly show that GVHD never induces IL-2 transcripts in the skin and only induces IL-2 transcripts in the spleen during the first week, whereas levels of IL-1 transcripts continue to increase throughout the entire 4 weeks. Administration of an IL-1 receptor antagonist after the termination of the IL-2 response and after the establishment of GVHD significantly increases long-term survival, confirming the central role of IL-1 as an effector molecule of GVHD and suggesting new therapeutic strategies for this disorder.

Animals↗
PubMed1991

Lymphocytes with a CD4+ CD8- CD3- phenotype are effectors of experimental cutaneous graft-versus-host disease.

Graft-versus-host disease (GVHD) is known to cause profound dysregulation of the immune system, although its effector mechanisms are poorly understood. We now describe an effector lymphocyte of unusual phenotype in the skin of mice with GVHD. This cell is of donor origin and expresses several T-cell surface proteins including Thy-1, CD2, and CD4 but does not express CD8, CD3, NK1.1, or macrophage antigens. Mononuclear cells of this phenotype are the predominant lymphocyte in the epidermis of mice with GVHD 3 weeks after transplant but are not detected in transplanted mice without GVHD. Isolation and transfer of these lymphocytes into secondary recipients causes epidermal damage characteristic of GVHD. These data demonstrate that CD4+ CD8- CD3- lymphocytes are an important effector population that can be amplified outside the thymus and that can mediate target organ damage of GVHD.

Animals↗
PubMed1991

Inhibition of interleukin-1 by an interleukin-1 receptor antagonist prevents graft-versus-host disease.

Graft-versus-host disease (GVHD) is the major complication of allogeneic bone marrow transplantation (BMT). Dysregulation of inflammatory monokines such as tumor necrosis factor alpha (TNF alpha) has been noted in both clinical and experimental GVHD. We present evidence that interleukin-1 (IL-1), another inflammatory monokine, is an important mediator of GVHD. Expression of the gene for IL-1 alpha as well as the gene for TNF alpha is increased in the skin of mice with GVHD. Inhibition of IL-1 function by the in vivo administration of IL-1 receptor antagonist (IL-1ra) reduces the immunosuppression and mortality of GVHD without impairing the engraftment of hematopoietic stem cells. GVHD thus appears to be a systemic inflammatory process in which monokines, especially IL-1, appear to be important mediators. Inhibition of IL-1 by IL-1ra represents a novel approach to the understanding and control of GVHD.

Animals↗
PubMed1990

Newborn screening for sickle cell disease. When is an infant 'lost to follow-up'?

Success of programs to screen newborns for sickle cell disease depends on timely follow-up. Education regarding fever and splenic palpation, and initiation of prophylactic penicillin therapy, will reduce morbidity and mortality and should occur prior to 4 months of age. However, contacting parents to permit implementation of care may be difficult, particularly in large urban populations; only nine (36%) of 25 infants recently identified as having sickle cell disease arrived at our institution for initial appointments. Medical providers must be aware of medical and legal obligations related to follow-up of newborns with sickle cell disease to prevent untoward events in "missed cases."

Follow-Up Studies↗
PubMed1989

Cariogenicity of a lactate dehydrogenase-deficient mutant of Streptococcus mutans serotype c in gnotobiotic rats.

A lactate dehydrogenase-deficient (Ldh-) mutant of a human isolate of Streptococcus mutans serotype c was tested in a gnotobiotic rat caries model. Compared with the wild-type Ldh-positive (Ldh+) strains, it was significantly (alpha less than or equal to 0.005) less cariogenic in experiments with two different sublines of Sprague-Dawley rats. The Ldh- mutant strain 044 colonized the oral cavity of the test animals to the same extent as its parent strain 041, although its initial implantation was slightly but not significantly (P greater than or equal to 0.2) less. Multiple oral or fecal samples plated on 2,3,5-triphenyltetrazolium indicator medium revealed no evidence of back mutation from Ldh- to Ldh+ in vivo. Both Ldh+ strain 041 and Ldh- strain 044 demonstrated bacteriocinlike activity in vitro against a number of human strains of mutans streptococci representing serotype a (S. cricetus) and serotypes c and e (S. mutans). Serotypes b (S. rattus) and f (S. mutans) and strains of S. mitior, S. sanguis, and S. salivarius were not inhibited. Thus, Ldh mutant strain 044 possesses a number of desirable traits that suggest it should be investigated further as a possible effector strain for replacement therapy of dental caries. These traits include its stability and low cariogenicity in the sensitive gnotobiotic rat caries model, its bacteriocinlike activity against certain other cariogenic S. mutans (but not against more inocuous indigenous oral streptococci), and the fact that it is a member of the most prevalent human serotype of cariogenic streptococci.

Animals↗