Cytokines and immunoglobulin in rheumatic heart disease: production by blood and tonsillar mononuclear cells.

Rheumatic fever and rheumatic heart disease are considered to result from abnormal immune responses after Group A streptococcal pharyngitis. Production of interleukin 1 (IL-1), tumor necrosis factor-alpha (TNF), interleukin 2 (IL-2) and immunoglobulin (Ig) by blood and tonsillar mononuclear cells from rheumatic or healthy children was measured after stimulation in vitro by pokeweed mitogen (PWM) or the streptococcal extracellular product, blastogen A (BLA). Tonsillar cells from patients with rheumatic heart disease produced significantly less IL-1, TNF, IL-2, and Ig than control tonsillar cells. In contrast, blood mononuclear cell cultures from rheumatic children produced more TNF and IL-2 than controls. Our findings suggest that abnormal regulation of cytokine and Ig production may contribute to the pathogenesis of acute rheumatic fever and rheumatic heart disease.

Augmentation of cytotoxic activity by mitogens in rheumatic heart disease.

Natural killer cell activity and alterations in cytotoxicity after culture with streptococcal blastogen A and phytohemagglutinin (PHA) were examined in patients with inactive rheumatic heart disease (RHD) and control patients. Natural cytotoxic activity of mononuclear cells (MNC) did not differ between RHD and control patients with either peripheral blood or tonsils. In cultured blood MNC the level of cytotoxic activity stimulated by blastogen A was significantly greater in patients with RHD at all effector:target cell ratios. These differences in cytotoxic activity were not observed with cultured tonsillar MNC. In similar experiments with a different group of patients, culture with PHA or blastogen A both produced a significantly greater increase in cytotoxic activity in blood MNC from patients with RHD. The increase was significantly lower with PHA than with blastogen A. The ability of mitogens to differentially augment cytotoxic activity in cells from the blood of patients with RHD implies that a population of cells exists in these patients that could be activated during acute rheumatic fever to play a role in pathogenesis.

Functional alterations in non-T cells in rheumatic heart disease.

The mediation of the T cell lymphoproliferative response to streptococcal blastogen A by non-T mononuclear cells was studied in patients with rheumatic heart disease (RHD) and control subjects. Non-T cells are essential for T cell response to blastogen A. Non-T cells from RHD patients were less effective in enabling the T lymphocyte response to blastogen A than control non-T cells though no consistent difference was observed in the response to phytohaemagglutinin. The results suggest that a functional alteration is present in the non-T cells from RHD patients which might be related to the pathogenesis of the disease.

Cellular immune responses to extracellular streptococcal products in rheumatic heart disease.

The lymphocyte transformation responses to purified preparations of two extracellular products of group A streptococci (blastogen A and nuclease B), to phytohemagglutinin, and to Candida albicans antigen were measured in tonsillar and peripheral blood lymphocytes from patients with rheumatic heart disease (RHD) and suitably matched nonrheumatic (control) subjects. The mean phytohemagglutinin dose responses of tonsillar and peripheral lymphocytes from RHD patients were essentially indistinguishable from those of controls. In contrast, the responses of tonsillar and peripheral blood lymphocytes to the two extracellular products of group A streptococci were significantly lower in RHD patients than in nonrheumatic control subjects. Candida antigen produced very little stimulation of lymphocytes in any of the subjects. The geometric means of antibody levels against streptolysin O, nuclease B, and nicotinamide adenine dinucleotidase showed no consistent differences between the control group and the group of RHD subjects. Group A streptococci were isolated from the tonsils of approximately 25% of both groups of subjects. The RHD patients clearly had a depressed cellular immune response to the two purified streptococcal extracellular antigens. The equal frequency in recovery of group A streptococci from tonsils and the absence of consistent difference in titers of humoral antibodies to streptococcal extracellular antigens, particularly nuclease B, suggest that this differential response is not due to a lower level of stimulation by repeated exposure to group A streptococcal products.

Streptococcal adherence to pharyngeal cells of children with acute rheumatic fever.

The adherence of strains of group A Streptococcus to pharyngeal cells from Egyptian children with acute rheumatic fever (RF) was examined. Nine RF-associated and eight unassociated streptococcal strains were tested in vitro for adherence to pharyngeal cells from 11 patients with acute RF and eight normal subjects. RF-associated streptococcal strains adhered more avidly to pharyngeal cells of patients with acute RF (mean, 11.8 bacteria/cell) than did unassociated strains (mean, 5.9 bacteria/cell; P less than 0.05). The difference in mean adherence could be attributed to certain RF-associated strains. There was no significant difference in adherence when pharyngeal cells from controls were used. Furthermore, one RF-associated streptococcal strain was found to adhere considerably more avidly to pharyngeal cells of patients with RF than to those of controls.

Lymphocytes binding C-reactive protein and streptococcal membranes in acute rheumatic fever.

Peripheral blood lymphocytes binding CRP and streptococcal membrane antigens were studied in 19 patients with ARF with the use of a number of paired analyses for cell surface markers. A small fraction (6.9%) of T cells showed binding to streptococcal membrane. A large degree of overlap (38% to 46%) occurred in membrane-binding T cells and those with identifiable CRP. One third of T gamma cells showed CRP bindings, and approximately one quarter to T gamma cells in both ARF patients and normal controls showed membrane la antigen. A considerable concordance (50% to 75%) was noted between T cells binding streptococcal membrane and cells positive for la antigen. In contrast to T cells, B cells bearing CRP showed less overlap (mean 11%) with cells binding streptococcal membrane. Since B cells with concomitant surface immunoglobulin and la antigen constituted the major lymphocyte subpopulation binding streptococcal membrane antigens, relative exclusion of streptococcal membrane binding by B cells with surface CRP may represent natural protective modulation whereby proportions of potential antigen-binding B cells are defused by lymphocyte membrane CRP.

Lymphocytes binding C-reactive protein during acute rheumatic fever.

Lymphocytes binding C-reactive protein (CRP) were studied in 31 patients with acute rheumatic fever and 30 controls who were children. Marked elevations in both proportions and absolute numbers of CRP-binding lymphocytes were recorded in rheumatic fever (P less than 0.001). No clear correlation was noted between plasma CRP as quantitated by radioimmunoassay and proportions or numbers of CRP-binding cells. Double-labeling experiments indicated that 60-80% of CRP-binding lymphocytes also showed Fc receptors reacting with fluorescein-conjugated IgG aggregates. Passage of lymphocytes over Ig--anti-IgG columns, removed cells bearing surface Ig but not CRP-binding lymphocytes. Studies of T-cell subpopulations indicated no overlap between Tmicron- and CRP-binding cells; however about half of Tgamma-cells showed concurrent CRP binding. "Active" T-cell rosetting cells did not bind CRP. A 12-15-h incubation of lymphocytes at 37 degrees C in 5% CO2-air showed persistence of CRP binding in substantial proportions of cells particularly in acute rheumatic fever. CRP-binding lymphocytes may represent a marker for immunologically committed cells in acute rheumatic fever.

Lymphocyte surface markers in acute rheumatic fever and post-streptococcal acute glomerulonephritis.

Lymphocyte cell-surface markers were examined in forty children with acute rheumatic fever (ARF) and twelve with acute post-streptococal glomerulonephritis (AGN) and compared to thirty-six normal controls of similar age. Cell-surface-marker studies included surface Ig using fluorescein-labelled F(ab)2 anti-F(AB')2, IgG aggregate binding cells, and EAC rosettes. T cells were identified both as 'active' rosettes and total E-binding cells. Proportions and absolute numbers of cells bearing surface Ig and Fc receptors were elevated in subjects with AGN (Pless than0-01-0-5), whereas proportions of cells producing EAC rosettes were diminished. Patients with acute rheumatic carditis or chorea showed a substantial elevation in proportions and numbers of active T-cell rosettes (Pless than0-01). Streptococcal antigen binding cells capable of forming rosettes with autologous cells coated with group A streptococcal membranes were elevated in the acute phase of both rheumatic fever and acute glomerulonephritis(Pless than0-01). The majority of such cells were removed by passage over insolubilized Ig-anti-IgG columns and appeared to be B cells.

Antibodies reacting with cytoplasm of subthalamic and caudate nuclei neurons in chorea and acute rheumatic fever.

46% of sera from 30 children with rheumatic chorea showed IgG antibody reacting with neuronal cytoplasm of human caudate and subthalamic nuclei. The antibody was also detected in 14% of 50 children with active rheumatic carditis. 55 normal control sera, as well as 148 sera from a broad variety of other disease states showed a low prevalence (1.8-4.0%) of positive reactions. In rheumatic chorea the presence of anti-neuronal antibody appeared to correlate with severity and duration of clinical attacks. Antibody reacting with neuronal cytoplasm was completely removed by absorption with Group A streptococcal membranes or with isolated human neurons from caudate nucleus. Partial absorption of antibody was also recorded using Group A cell wall preparations but not with Group A carbohydrate. No absorption of positive reactions was seen with streptococcal Group D membranes or cell walls. In rheumatic chorea, anti-neuronal antibody appeared to represent cross-reaction with antigens shared by Group A streptococcal membranes.

Peripheral blood T and B lymphocytes during acute rheumatic fever.

Proportions and total numbers of thymus-derived (T) and bone marrow-derived (B) peripheral blood lymphocytes were studied in 53 patients with acute rheumatic fever, diagnosed on the basis of modifified Jones criteria. An elevation in both proportions and absolute numbers of cells bearing surface Ig was found in most patients, particularly during the first 7 days after onset. Conversely, T-cell proportions and numbers were often found to be depressed early in the acue phases of rheumatic fever. Proportions of cells bearing surface Ig did not correlate with another B-cell marker, the aggregated gamma globulin receptor, suggesting that such cells bearing surface Ig were not all B lymphocytes. Incuvation for 20 h at 37 per cent C of cells showing high proportions of surface Ig-bearing surface Ig in both normal and rheumatic fever subjects, although there was no appreciable increment in proportions of lymphocytes expressing T-cell markers. Patients with initial attacks showed higher percentages and total numbers of Ig-bearing lymphocytes (P smaller than 0.01) than did those with rneumatic fever recurrences. Elevations in numbers and proportions of peripheral blood lymphocytes bearing Ig appeared to correlate with the relative acute nature of the rheumatic fever attack.