Vaccine immune response and side effects with the use of acetaminophen with influenza vaccine

The purpose of this study was to determine whether acetaminophen impairs the immune response to influenza vaccine. Influenza vaccine is an under-utilized preventive measure, partly because of the unfounded perception that fever and myalgias frequently follow vaccination. While acetaminophen may decrease these infrequent side effects, it may also alter the immune response to vaccination. We compare the effect of acetaminophen with placebo on the humoral immune response to the 1991-1992 commercially available influenza vaccine. We studied 60 healthy, elderly subjects from a geriatric clinic and 20 infirm, elderly subjects from a nursing home. The subjects were randomly assigned to receive placebo or acetaminophen (1,000 mg every 6 h) for 2 days. Acetaminophen did not depress or enhance the immune development of serum hemagglutination inhibition antibody to the three vaccine antigens. The systemic side effects of fever and myalgia were uncommon in both groups. The healthy elderly subjects mounted a significantly better immune response to the influenza virus A/Taiwan/1/86 (H1N1) vaccine strain than did the infirm elderly subjects (geometric mean titer, 115 versus 51; P = 0.003). The functional activity score obtained by using the chronic healthy evaluation component of the Acute Physiology and Chronic Health Evaluation system could be used to distinguish the healthy from the infirm elderly (scores of 1.27 versus 3.75, P < 0.001). Acetaminophen neither depressed nor enhanced the serum antibody response to the vaccine in the healthy and infirm elderly subjects studied.

Clonal populations of T cells in normal elderly humans: the T cell equivalent to "benign monoclonal gammapathy"

To determine whether T cells, like B cells, can become clonally expanded in normal individuals as a function of age, we compared the T cell V beta repertoire of cord blood to that of peripheral blood from normal donors over 65 yr of age. T cells from elderly subjects contained expanded subsets (greater than the mean+three standard deviations) of T cell receptor (TCR) V beta populations. These expanded subsets were observed primarily among CD8, but not CD4 cells, represented up to 37.5% of all CD8 cells, and were present in most elderly subjects. An expanded V beta 5.2/3 CD8 subset and a V beta 6.7a CD8 subset from separate donors were analyzed by reverse transcriptase-polymerase chain reaction, cloning and sequencing of the TCR beta chain VDJ junction. In both cases the expanded subsets were mono- or oligoclonal while control CD4 populations were polyclonal. Using two-color flow cytometry it was possible to identify the expanded V beta 6.7a subset as CD8+ CD28-CD11b+ cells. In three of five random old subjects similar expansions of V beta subsets were found specifically in the CD8+ CD28- subpopulation, an interesting subset of cytotoxic T lymphocytes, known to lack proliferative responses to TCR stimuli. It is common practice to use the demonstration of clonality as a diagnostic indicator for T cell lymphoma/leukemia. In view of the high frequency of expanded T clones of T cells in normal elderly subjects the diagnostic usefulness of this test should be reexamined.

Active infective endocarditis: surgical approach

From January 1982 to December 1991, 65 interventions were performed in 61 patients with active infective endocarditis (IE): 32 on native valves (Group 1) and 33 on prosthetic valves (Group 2). In Group 1, 23 patients had a known previous valve disease; major preoperative clinical complications occurred in 16 patients (50%); 84% were in NYHA classes III and IV. In Group 2 major preoperative clinical complications occurred in 13 patients (44.8%); 86% were in NYHA classes III and IV. The mean time interval between the onset of hemodynamic impairment of varying degrees and surgery was 13 +/- 15 days for Group 1, and 8 +/- 11 days for Group 2. In all cases, the native valves or prostheses were replaced by mechanical valve prostheses. Particular procedures were performed in three patients in Group 1 and five patients in Group 2. In Group 1 there were 8 hospital deaths (25%) and 11 (34.4%) non-fatal complications. In Group 2 there were 9 deaths (31%) and 14 (48.3%) non-fatal complications. Risk factors for hospital death were "preoperative low cardiac output syndrome" and "time interval between the onset of cardiac failure and surgery" in Group 1, "cardiac failure+sepsis" in Group 2, "time interval between the onset of cardiac failure and surgery" and "particular procedures" in all 61 patients. Sepsis alone and the type of pathogenic agent does not significantly affect the risk of death. The recurrence of acute IE was 12.6% in Group 1, and 20% in Group 2. The incidence of reintervention was 12.6% in Group 1 and 35% in Group 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Age-dependent appearance of non-major histocompatibility complex-restricted helper T cells

T cells which recognize antigen in association with self major histocompatibility complex (MHC) molecules are positively selected within the thymus. This results in skewing of the T-cell repertoire toward the recognition of antigenic peptides presented by self MHC molecules. While the thymus gland involutes at a relatively young age, bone marrow function and the size of the peripheral T-cell pool are maintained with age. We have investigated the MHC restriction of helper T-cell function for B-cell production of specific antibody in mice of different ages. Splenic helper T cells from 2- to 3-month old mice immunized with phosphocholine-keyhole limpet hemocyanin conjugate were MHC-restricted as defined by their capacity to induce phosphocholine-specific antibody synthesis by syngeneic but not by allogeneic B cells. In contrast, splenic T cells from immunized 18- to 20-month-old mice induced specific anti-phosphocholine antibodies by both syngeneic and allogeneic B cells. No evidence of polyclonal immunoglobulin synthesis was detected. The ability of T cells from old mice immunized with phosphocholine-keyhole limpet hemocyanin to induce phosphocholine-specific antibody synthesis by B cells from allogeneic mice was inhibited by T cells from immunized young mice. These findings suggest that non-MHC-restricted T-cell helper activity in old mice results from the loss of T cells, present in young mice, which suppress non-MHC-restricted helper cells.

Posterior annuloplasty in the surgical treatment of mitral insufficiency

One hundred and twenty-nine patients underwent posterior mitral annuloplasty with a Gore-Tex tube for mitral regurgitation between January 1982 and June 1991. The hospital mortality was 1.5% (CL = 0.5%-2.5%). The overall survival of hospital survivors was 96.5% +/- 2.7% at five and 86.2% +/- 7.6% at nine years, freedom from cardiac death was 99.1% +/- 0.9% and 95.2% +/- 3.9%, respectively. The actuarial freedom from embolism was 96.1% +/- 2.3% at five and 88.5% +/- 5.5% at nine years. The freedom from endocarditis (one patient) was 100% and 92.6 +/- 7.1%, respectively. Reoperation was necessary in six cases between one and 72 months after the operation (mean 38.5 +/- 30.5 months). The etiology of the valvular insufficiency was rheumatic in all reoperated cases. The freedom from reoperation was 94.1% +/- 3.2% at five and 87.2% +/- 5.6% at nine years. There was no mortality at reoperation. Of the 117 patients alive at the end of follow up and not requiring reintervention, 113 (96.6%) showed good functional improvement and were in NYHA functional class I or II. We conclude that both the immediate and long-term results of reconstructive surgery using the technique of inserting a half-ring on the posterior mitral annulus compare favorably with those obtained using other annuloplasty methods.

[Cytogenetic patterns in Warthin tumor]

Our systematic studies of different types of benign and malignant salivary neoplasms in humans were initiated about two years ago. Analysis of karyotypes revealed that virtually all tumors are associated with chromosomal abnormalities. That those abnormalities may also take part in tumor initiation and progression is suggested by the association of specific chromosome rearrangement with particular cancers. We here with report cytogenetical observation in five Warthin's tumors giving particular attention to the possible occurrence of cells with (a) a normal karyotype or with (b) numerical changes, either loss of the Y chromosome or monosomy 4. The present series od adenolymphomas was karyotyped by a direct chromosomal analysis method. The method reported was highly successful, in several types of tumors showing the possibility of having good banded metaphases. All Warthin's tumors showed stemline (S) with a normal karyotype. These normal cells constituted the only S in two cases and the primary S in the other three cases. The normal cells observed in all adenolymphomas could be interpreted as outgrowing stroma cells. Most types of previously well-studied benign human tumor types, however (meningiomas, pleomorphic adenomas, lipomas), has a S group with a normal karyotype, regardless of the the tissue culture technique used. Thus, we believe that these normal cells usually represent neoplastic elements. Furthermore, we think that all benign tumors originate with a rather normal S, which, however, as the first indication of neoplastic transformation, shows chromosomal instability, such as the loss of chromosomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of age on the expressed B cell repertoire: role of B cell subsets

Aged humans and experimental animals are impaired in their responses to most foreign antigens although they produce greater amounts of autoantibodies. We have examined the effect of age on the production of antibodies to a prototypic foreign antigen, sheep erythrocytes (SRBC), and to a prototypic autoantigen, bromelain-treated mouse erythrocytes (BrMRBC), in young and old mice before and after immunization with SRBC. Old mice express more anti-BrMRBC plaque-forming cell (PFC) antibodies before and an even greater number after immunization with SRBC than young mice. Conversely, old mice produce far fewer anti-SRBC PFC than young mice following immunization with SRBC. We hypothesized that the differences in the responses of old mice to BrMRBC and SRBC reflects differences in the activity of CD5+ and CD5- B cells. To test this hypothesis we immunized young and old mice with foreign antigens reported (and confirmed in our studies) to stimulate CD5+ B cells [TNP-ficoll and phosphorylcholine-keyhole limpet hemocyanin (KLH)] or CD5- B cells (SRBC and TNP-KLH). We found that the PFC response of old mice to antigens mediated by CD5+ B cells was equal to or greater than that of young mice. In contrast the PFC response of old mice induced by antigens mediated by CD5- B cells was only 10% that of young mice. Thus it appears that the immune response of old mice is well maintained for antigens which elicit a CD5+ B cell response but not for those which elicit a CD5- B cell response.(ABSTRACT TRUNCATED AT 250 WORDS)

Enhancement of glycine release from human brain cortex synaptosomes by acetylcholine acting at M4 muscarinic receptors

Synaptosomes prepared from fresh specimens of human cerebral cortex were labeled with [3H]glycine ([3H]Gly) and distributed in parallel superfusion chambers. Exposure to 15 mM KCl evoked a tritium overflow which was largely prevented by 10 mM Mg++, suggesting a consistent component of Ca(++)-dependent [3H]Gly release. Acetylcholine (ACh; 1-100 microM), added during K(+)-depolarization, increased the release of tritium in a concentration-dependent manner (maximal effect, 60%; EC50 = 7 microM). Oxotremorine (1-100 microM) mimicked ACh. The effect of 10 microM ACh was insensitive to the nicotinic antagonist mecamylamine (100 microM), but it was blocked by the muscarinic antagonist atropine (0.1 microM). Three muscarinic receptor antagonists, pirenzepine, AF-DX 116 (11-[12-[diethylamino-methyl]-1-piperidinyl]acetyl-5-11-dihydro -6H-pyrido-[2-3-b][1,4]benzodiazepine-6-one) and himbacine, endowed with relative selectivity for various muscarinic receptor subtypes, prevented with differential affinities the effect of 10 microM ACh. Himbacine was the most potent antagonist of ACh, its pA2 (8.34) being 20- or 50-fold higher than that of pirenzepine (7.27) or AF-DX 116 (6.65). It is concluded that: 1) ACh can increase the release of Gly in human cerebral cortex; 2) the interaction occurs through muscarinic receptors which resemble most the M4 subtype; and 3) considering that Gly is required to activate the N-methyl-D-aspartate glutamate receptor, the ACh-evoked Gly release may represent a linkage between cholinergic and glutamatergic transmission, two systems strongly implicated in cognitive processes.

Increased serum HLA class I molecule levels in elderly human responders to influenza vaccination

Increased cell surface expression and serum levels of HLA class I molecules have been shown to occur in normal elderly humans. Elderly subjects (65 years and older) generally also have a poorer response to influenza vaccine than younger adults. Some 30 to 40% of elderly subjects do not respond to influenza vaccination. Sera from 20 elderly subjects with a positive response to influenza vaccine (HAI antibody titer > 40) and 20 subjects who did not respond (HAI antibody titer < 40) were randomly selected and the levels of soluble HLA class I molecules determined before and after vaccination. The subjects who responded had higher serum HLA class I levels both before and after vaccination than did non-responders. Two weeks after vaccination non-responders showed similar serum HLA class I levels (1.78 mg/ml +/- 0.62) as compared to prevaccination levels (1.73 mg/ml +/- 0.49). The responders showed significantly higher levels of soluble HLA class I molecules following vaccination (2.64 mg/ml +/- 0.99) as compared to pre-vaccination (2.08 mg/ml +/- 0.85, p = 0.00001). Our results suggest that measuring soluble HLA class I molecules in the serum may be useful in assessing the adequacy of response to influenza vaccination in the elderly population.

Altered major histocompatibility complex-restricted antigen recognition by T cells from elderly humans

Positive selection of T cells within the thymus gland leads to major histocompatibility complex (MHC)-restricted recognition of antigen by T lymphocytes. As the thymus gland involutes with age, altered MHC-restricted antigen recognition by T cells from elderly humans would be expected. We have tested this hypothesis by comparing the proliferative response of T cells and T cell clones from aged and young subjects to influenza determinants presented by autologous or allogeneic antigen-presenting cells (APC). Under conditions in which the allogeneic mixed lymphocyte reaction was minimal, T cells from six of seven aged donors but only one of seven young donors were stimulated by influenza vaccine presented by allogeneic APC. More importantly, one-half of the influenza-specific T cell clones derived from aged donors, but none of the clones derived from young donors, were activated by influenza vaccine presented by allogeneic APC. While 80% of the MHC-nonrestricted influenza-specific T cell clones expressed the gamma/delta T cell receptor, 20% of these clones expressed the alpha/beta T cell receptor. Thus, changes in MHC-restricted antigen recognition by T cells and in altered distribution of alpha/beta versus the gamma/delta T cell receptor bearing antigen-specific T cell clones occur with aging.

[Repeat myocardial revascularization]

Eighty-two consecutive patients undergoing reoperation for coronary revascularization from January 1980 to November 1990 were reviewed to determine early and late results and predictors of survival. Seventy patients were male and 12 female; age ranged from 36 to 75 years (mean 56.4 +/- 8.1). All were symptomatic for angina. The mean interval between first and second operation was 62.8 +/- 47.8 months (range 1 to 220 months). Angiographic indications for reoperation were: graft failure (34.1%), progression of atherosclerosis in the native coronary circulation (6.1%) and combination of the two (59.8%). Mean ejection fraction was 45.9 +/- 10.2 (range 11 to 67). Surgical indication was elective in 79.3%, urgent in 14.6% and emergent in 6.1%; 199 grafts were performed (2.4 +/- 1 grafts/patient). Hospital mortality was 6.1% (5 cases). Late mortality was 5.2% (4 cases). Actuarial survival rate (including hospital mortality) was 87.9% at 3, 5 and 10 years. Multivariate analysis identified left main stenosis (p = 0.00001), family history of coronary disease (p = 0.003), urgent/emergency operation (p = 0.015) as predictors of increased in-hospital mortality; postoperative myocardial infarction (p = 0.002) and preoperative heart failure (p = 0.01) as predictors of increased late mortality. Follow-up of in-hospital survivors (mean interval 42.7 +/- 25.8 months, range 3 to 120 months) documented 27 cardiac major events (other than death) in 24 patients (32.9%). Actuarial rates of freedom from major cardiac events were 70%, 52.9% and 48.1% at 3, 5 and 10 years respectively. Multivariate analysis identified preoperative ejection fraction (p = 0.01) as predictor of recurrence of angina and preoperative heart failure (p = 0.02) as predictor of occurrence of cardiac major events.

[Nasocardiac reflex evoking during rhinoseptoplasty. Description of a clinical case]

We report a case of nasocardiac reflex which occurred during a septorhinoplasty. Management and preventive treatment is briefly discussed.

Evaluation and treatment of secondary tricuspid insufficiency

To define the role of functional tricuspid insufficiency and right ventricular (RV) failure in patients with mitral disease, the data of 121 patients with secondary tricuspid insufficiency that underwent mitral valve replacement (MVR) from January 1982 to December 1987 were analyzed. The mitral hemodynamic lesion was: stenosis in 41 patients (33.9%); insufficiency in 11 (9.1%) and mixed stenosis and insufficiency in 69 (57.0%). NYHA functional class was: II in 4 patients (3.3%), III in 78 (64.5%) and IV in 39 (32.2%). In 100 cases (group 1) with tricuspid insufficiency defined as moderate or severe, a De Vega annuloplasty was performed while in 21 (group 2) with mild tricuspid insufficiency, no tricuspid surgical procedure was performed. Hospital deaths occurred in 17 of 121 patients [14% (CL 10.8-17.0)]. There was no significant difference in hospital mortality between group 1 and group 2 (15% vs 9.5%; P = 0.75). Incremental risk factors for hospital mortality as determined by multivariate analysis, include: cardiothoracic ratio (P = 0.0016), total aortic cross-clamp time (P = 0.006), associated cardiac disease (P = 0.0209) and emergency operations (P = 0.0318). Mean follow-up of surviving patients was 50.1 +/- 28.1 months. Late deaths occurred in 16 patients [15.4% (CL 11.7-18.7)]. The actuarial survival rate was 85.6% and 73.8% at 5 and 9 years, respectively. Nine patients [8.6% (CL 5.9-11.3)] required reoperation. There was no significant difference between group 1 and group 2 in the rate of late cardiac related deaths (5.9% vs 5.3%, P = 0.66) and of tricuspid reoperations (4.7% vs 5.3%, P = 0.62).(ABSTRACT TRUNCATED AT 250 WORDS)

[Surgical revascularization in acute myocardial infarct]

To determine the potential role of emergency surgical revascularization as treatment of acute myocardial infarction (AMI), results in 79 patients undergoing operation for myocardial revascularization during AMI from January 1986 to January 1991 were reviewed. Clinical characteristics for inclusion in the study were: 1) emergency operation; 2) persistent angina not controlled by medical therapy; 3) fixed ST segment elevation until surgical procedure, independently from magnitude of enzymatic levels. The 79 patients were divided in 2 groups: 27 with AMI or evolving AMI (Group 1); 52 with AMI due to complications during PTCA (Group 2). Twenty-eight patients had extremely severe clinical conditions. Mean interval between the beginning of AMI and operation was 4.2 +/- 6.7 hours, with a statistically significant difference between Group 1 (8.7 +/- 10.0) and Group 2 (1.9 +/- 1.0). One hundred ninety-two grafts were performed (2.4 +/- 1.1 grafts/patient). Overall hospital mortality was 10.1% (CL 6.7-13.3) (8 deaths) with a difference between Group 1 [18.5% (CL 10.7-25.3)] and Group 2 [5.8% (CL 4.7-6.6)] (p = 0.074). The incidence of perioperative myocardial infarction was 30.4% (CL 24.9-35.1) for that one in the area of ischemic muscle and 2.6% (CL 0.8-4.1) for infarction in remote muscle. Multivariate analysis for the entire series (79 patients) identified as independent predictors of increased in-hospital mortality: preoperative cardiogenic shock (p = 1.000E-4) and hyperlipidemia (p = 0.008). In Group 1 multivariate analysis identified as independent predictors of increased in-hospital mortality: the attempt of revascularization by PTCA and hyperlipidemia; in Group 2: preoperative need of mechanical ventilatory support.(ABSTRACT TRUNCATED AT 250 WORDS)

T helper cell-dependent, microbial superantigen-induced murine B cell activation: polyclonal and antigen-specific antibody responses

Microbial superantigens (SA), bound to human B cell surface MHC class II molecules, have been shown to promote direct, "cognate" interaction with SA-reactive autologous Th cells, resulting in polyclonal Ig production. To investigate the potential for microbial SA to support Th cell-dependent, Ag-specific antibody responses, we have extended our studies to the murine system. BALB/c Th cell lines (TCL), specific for either the Mycoplasma arthritis-derived SA or the Staphylococcus aureus-derived toxic shock syndrome toxin-1) were generated. These TCL cells are SA-specific, functionally noncross-reactive, and utilize distinct TCR V beta gene families. Coculture of SA-reactive TCL cells and syngeneic B cells bearing the relevant SA results in B cell proliferation and polyclonal IgM and IgG production. In contrast, Ag-specific (SRBC-specific) antibody-forming cells are only generated in cultures that also contain SRBC. Thus, microbial SA-mediated Th-B cell interactions induce both polyclonal B cell activation and provide selective help for the proliferation and/or differentiation of B cells that have encountered specific Ag. In additional studies, we determined that the in vivo administration of toxic shock syndrome toxin-1 to young, athymic (nude) BALB/c mice results in SA binding to splenic B cells, rendering these B cells effective stimulators of and targets for SA-reactive helper TCL cells. Taken together, these results demonstrate that microbial SA mediate productive Th-B cell interactions analogous to those that occur during allospecific Th-B cell interactions in vitro and GVHD in vivo. These findings are consistent with the hypothesis that microbial SA represent environmental factors that may trigger autoimmune disease in the genetically susceptible host.

T helper cell-dependent, microbial superantigen-induced murine B cell activation: polyclonal and antigen-specific antibody responses

Microbial superantigens (SA), bound to human B cell surface MHC class II molecules, have been shown to promote direct, "cognate" interaction with SA-reactive autologous Th cells, resulting in polyclonal Ig production. To investigate the potential for microbial SA to support Th cell-dependent, Ag-specific antibody responses, we have extended our studies to the murine system. BALB/c Th cell lines (TCL), specific for either the Mycoplasma arthritis-derived SA or the Staphylococcus aureus-derived toxic shock syndrome toxin-1) were generated. These TCL cells are SA-specific, functionally noncross-reactive, and utilize distinct TCR V beta gene families. Coculture of SA-reactive TCL cells and syngeneic B cells bearing the relevant SA results in B cell proliferation and polyclonal IgM and IgG production. In contrast, Ag-specific (SRBC-specific) antibody-forming cells are only generated in cultures that also contain SRBC. Thus, microbial SA-mediated Th-B cell interactions induce both polyclonal B cell activation and provide selective help for the proliferation and/or differentiation of B cells that have encountered specific Ag. In additional studies, we determined that the in vivo administration of toxic shock syndrome toxin-1 to young, athymic (nude) BALB/c mice results in SA binding to splenic B cells, rendering these B cells effective stimulators of and targets for SA-reactive helper TCL cells. Taken together, these results demonstrate that microbial SA mediate productive Th-B cell interactions analogous to those that occur during allospecific Th-B cell interactions in vitro and GVHD in vivo. These findings are consistent with the hypothesis that microbial SA represent environmental factors that may trigger autoimmune disease in the genetically susceptible host.

Philadelphia chromosome and monosomy 7 in childhood acute lymphoblastic leukemia: a Pediatric Oncology Group study

During an 8-year period, 3,638 children from institutions of the Pediatric Oncology Group (POG) were diagnosed with acute lymphoblastic leukemia (ALL). Fifty-seven patients had Philadelphia chromosome-positive (Ph1) ALL. Blast cells obtained at diagnosis from 13 of these 57 cases (23%) were also found to have partial or complete monosomy 7 (-7). This subgroup of children with Ph1/-7 ALL was comprised primarily of older males with early B-lineage ALL. Bone marrow specimens from six Ph1/-7 patients were studied further using the polymerase chain reaction and primers that flank the ALL, and chronic myelogenous leukemia breakpoints to determine the molecular characteristic of the 9;22 translocation. Rearrangements were detected in RNA from bone marrow and/or peripheral blood cells of six patients, although four were in hematologic remission at the time of the analysis. Five cases showed the ALL breakpoint, while one child with Ph1/-7 showed the chronic myelogenous leukemia breakpoint. The induction failure rate was much higher in this subgroup (31%) as compared with Ph1-negative cases, and the projected duration of event-free survival reflected the aggressive nature of this subgroup because no children are projected to remain in remission at 2 years. ALL with both the 9;22 translocation and -7 appears to represent a unique and previously undescribed subgroup of childhood ALL associated with a particularly adverse outcome. Leukemic transformation in such patients may involve the interaction of a dominant oncogene (Ph1) and a tumor suppressor gene (-7).

[Anti-BHc determination in blood donors in São Paulo: should this test be adopted in Brazil?]

PURPOSE

to study the incidence of anti-HBc (core) as a surrogate marker for post-transfusion Non-A, Non-B Hepatitis (HNANB-PT) among blood donors in São Paulo, Brazil. TYPE: prospective, screening all blood donors from September to December, 1989 (nr. 2,773 donors).

PLACE

Sírio-Libanês Hospital and 9 de Julho Hospital (São Paulo).

PATIENTS

a total of 2,773 donors, 84% male and 16% female.

METHOD

the tests used were competitive ELISA for Anti-HBc.

MEASUREMENTS AND RESULTS

the repeated rah reactivity (RR) was 10.2% among all donors, with a higher incidence in males than in females (10.9% x 6.8% p less than 0.05 6y X2). Only 4.5% were borderlines, and 94.5% showed an absorbance/cut-off ratio less than 0.9.

CONCLUSIONS

despite the lack of prospective studies correlating HNANB-PT to surrogate markers (e.g. ALT and anti-HBc) in this country, the high incidence of anti-HBc in donors allows to conclude that it might be as high as reported in other countries. Although the costs related to the adoption of this test, its indication in other countries and its association with the newly-developed specific test (anti-HCV) supports the idea of anti-HBc as a screening test for HNANB-PT in Brazil, at least in the most developed blood centers in the country.

Mitral valve replacement with the SORIN valve. Long-term follow-up of 1,161 patients

From 1 March 1977 through 31 December 1987, 1,252 patients underwent mitral valve replacement with a SORIN-Biomedica 60 degrees tilting-disc prosthesis at our institution. Hospital mortality was 7.3% (91 patients); prosthesis-related deaths, expressed as a percentage of hospital mortality, accounted for 12.1% of these early deaths. The 1,161 patients who survived hospitalization have been followed up for a total of 4,835 patient-years (range, 1 to 128 months; mean, 50.4 +/- 27.3 months). Forty-three (3.7%) of these patients were lost to follow-up. The late mortality was 6.3% (1.5% +/- 0.2% per patient-year), and the 10-year actuarial survival rate, excluding hospital mortality, was 89.1% +/- 1.6%. The 10-year actuarial (and linearized) rates of freedom from valve-related complications were as follows: embolism, 94.4% +/- 1.0% (0.93% +/- 0.1% per patient-year); thrombosis of the prosthesis, 99.8% +/- 0.1% (0.06% +/- 0.03% per patient-year; hemorrhage, 93.7% +/- 1.5% (0.95% +/- 0.1% per patient-year); prosthetic valve endocarditis, 99.3% +/- 0.3% (0.14% +/- 0.05% per patient-year); reoperation, 90.6% +/- 2.1% (1.1% +/- 0.2% per patient-year); and overall complications, 76.6% +/- 2.5% (2.9% +/- 0.2% per patient-year). No structural deterioration was noted. These data not only confirm our previous reports concerning the reliability and durability of the SORIN prosthesis but also reveal a significant reduction, over the long term, in the overall incidence of valve-related complications.

T lymphocytes can mediate lysis of autologous melanoma cells by multiple mechanisms: evidence with a single T cell clone

The specificity analysis of a CD3+, WT31+, CD8+ cytotoxic T lymphocyte (CTL) clone (CTL 49), isolated from peripheral blood lymphocytes of a melanoma patient (no. 665) after mixed lymphocyte culture with an HLA-A2+ allogeneic lymphoblastoid cell line (VSKB-LCL), revealed that CTL 49 could lyse, in addition to HLA-A2+ lines, autologous HLA-A2- melanoma (Me665/2) and K562 targets. Killing of VSKB-LCL, but not of Me665/2, could be inhibited by anti-CD3 and by anti-HLA-A2 antibodies or by modulation of the CD3 complex. Cold-target competition studies showed that K562, but not VSKB-LCL, could compete with Me665/2 for lysis by CTL 49. However, unlike K562, Me665/2 could be lysed by CTL 49 in a Ca2(+)-independent fashion in 4 h and 18 h assays. CTL 49 expressed mRNA specific for tumor necrosis factor (TNF alpha) and, to a lesser extent, for lymphotoxin (TNF beta). Exposure of the clone to anti-CD3 antibodies induced the expression of interferon(IFN)-gamma-specific mRNA. Antibodies to TNF alpha, TNF beta and IFN reduced the lysis of Me665/2, but not of K562, by CTL 49 in 18-h cytotoxic assays. Antibodies to TNF alpha and to IFN gamma almost completely inhibited the lysis seen on Me665/2 (but not on K562), in 96-h assays, by supernatants isolated from VSKB-LCL- or anti-CD3-stimulated CTL 49 cells. Taken together, these data indicate that major-histocompatibility-complex-independent lysis of autologous tumor cells and of natural killer reference targets by the same alloreactive T cell clone are activities related at the level of target recognition but distinct at the level of the lytic hit. Thus, efficient lysis of autologous tumor cells results from a complex mechanism based upon direct effector-target interaction as well as on cytokine-mediated cytolytic effects.

Selective changes in expression of HLA class I polymorphic determinants in human solid tumors

Analysis of surgical biopsies with monoclonal antibodies (mAbs) to framework determinants of major histocompatibility complex class I antigens has shown that malignant transformation is frequently associated with a marked loss of these cell surface molecules. The present study sought to determine whether more selective losses of major histocompatibility complex class I expression occur. Multiple specimens from 13 different types of primary and metastatic tumors were tested utilizing mAb BB7.2, which recognizes a polymorphic HLA-A2 epitope. In each case, expression of HLA-A,B,C molecules was determined by testing with mAb W6/32 directed to a framework HLA class I determinant. We have found that in HLA-A2-positive patients (identified by reactivity of their normal tissues with mAb BB7.2), HLA-A2 products are not detectable or are reduced in their expression in 70-80% of endometrial, colorectal, mammary, and renal tumors; in 40-60% of soft-tissue, skin, ovary, urinary bladder, prostate, and stomach tumors; and in 25-30% of melanomas and lung carcinomas tested. All tumors expressed the framework HLA-A,B,C determinant. The HLA-A2 epitope recognized by mAb BB7.2 is located in a portion of the HLA-A2 molecule postulated to react with the T-cell receptor. Immune surveillance to tumors is thought to depend on cytotoxic T cells, which require corecognition of polymorphic HLA class I epitopes, and on natural killer cells, which are, on the contrary, activated by the absence of HLA class I antigens. The selective loss of an HLA class I polymorphic epitope shown in this study may explain the mechanism by which tumor cells escape both T-cell recognition and natural killer cell surveillance.