Sickening or Healing the Heart? The Association of Ficolin-1 and Rheumatic Fever

Rheumatic fever (RF) and its subsequent progression to rheumatic heart disease (RHD) are chronic inflammatory disorders prevalent in children and adolescents in underdeveloped countries, and a contributing factor for high morbidity and mortality rates worldwide. Their primary cause is oropharynx infection by Streptococcus pyogenes, whose acetylated residues are recognized by ficolin-1. This is the only membrane-bound, as well as soluble activator molecule of the complement lectin pathway (LP). Although LP genetic polymorphisms are associated with RF, FCN1 gene's role remains unknown. To understand this role, we haplotyped five FCN1 promoter polymorphisms by sequence-specific amplification in 193 patients (138 with RHD and 55, RF only) and 193 controls, measuring ficolin-1 serum concentrations in 78 patients and 86 controls, using enzyme-linked immunosorbent assay (ELISA). Patients presented lower ficolin-1 serum levels (p < 0.0001), but did not differ according to cardiac commitment. Control's genotype distribution was in the Hardy-Weinberg equilibrium. Four alleles (rs2989727: c.-1981A, rs10120023: c.-542A, rs10117466: c.-144A, and rs10858293: c.33T), all associated with increased FCN1 gene expression in whole blood or adipose subcutaneous tissue (p = 0.000001), were also associated with increased protection against the disease. They occur within the *3C2 haplotype, associated with an increased protection against RF (OR = 0.41, p < 0.0001) and with higher ficolin-1 levels in patient serum (p = 0.03). In addition, major alleles of these same polymorphisms comprehend the most primitive *1 haplotype, associated with increased susceptibility to RF (OR = 1.76, p < 0.0001). Nevertheless, instead of having a clear-cut protective role, the minor c.-1981A and c.-144A alleles were also associated with additive susceptibility to valvar stenosis and mitral insufficiency (OR = 3.75, p = 0.009 and OR = 3.37, p = 0.027, respectively). All associations were independent of age, sex or ethnicity. Thus, minor FCN1 promoter variants may play a protective role against RF, by encouraging bacteria elimination as well as increasing gene expression and protein levels. On the other hand, they may also predispose the patients to RHD symptoms, by probably contributing to chronic inflammation and tissue injury, thus emphasizing the dual importance of ficolin-1 in both conditions.

Increased M1 Macrophages Infiltration Is Associated with Thrombogenesis in Rheumatic Mitral Stenosis Patients with Atrial Fibrillation

Atrial fibrillation (AF) is the most common arrhythmia. In patients with AF, the role of macrophage subsets in thrombogenesis is unclear. In the present study, we analyzed the role of M1 and M2 macrophages and related cytokines in thrombogenesis of AF. Immunohistochemistry, Western blot, and TUNEL assay were used to detect M1/M2 macrophage infiltration, the expression pattern of IL-1β and inflammasome components, and apoptosis of cardiomyocytes in 71 specimens obtained from the left atrial appendage of patients with rheumatic mitral stenosis (MS) with or without thrombosis. We demonstrated that proinflammatory M1 macrophages were predominant in the atrium of MS patients with AF and thrombus. NLRP3 inflammasomes and IL-1β, which are primarily functional in macrophages, were activated in those patients. We also showed that increased cell death was associated with thrombogenesis in MS patients. These data indicate that infiltration of M1 macrophages and over-activation of NLRP3 inflammasomes may play a role in progressive atrial inflammation and thrombogenesis in rheumatic mitral stenosis patients with AF.

Circulating CD4+CD25+ T cells in rheumatic mitral stenosis

BACKGROUND AND AIM OF THE STUDY

Autoimmunity plays an essential role in the pathogenesis of rheumatic heart disease. Although the ongoing rheumatic process has been demonstrated with high levels of inflammatory markers, the cellular mechanism(s) of autoimmunity have not yet been investigated. The study aim was to examine levels of circulating CD4+CD25+ T cells in patients with rheumatic mitral stenosis, and to evaluate the relationship between regulatory CD4+CD25+ T-cell count and clinical and echocardiographic measures.

METHODS

A total of 42 patients with mitral stenosis was enrolled into the study, and 27 normal age- and gender-matched healthy subjects served as controls. All patients and controls underwent clinical, electrocardiographic, echocardiographic and laboratory evaluation. T-cell levels were determined with flow cytometry using monoclonal fluorescein isothiocyanate-labeled anti-CD4 and phycoerythrin-labeled anti-CD25 antibodies.

RESULTS

The circulating CD4+CD25+ T-cell count was significantly lower in patients with mitral stenosis than in controls (231 +/- 120 versus 372 +/- 180 per mm3; p = 0.001). The percentage ratio of CD4+CD25+ T cells to total leukocytes and lymphocytes was significantly lower in patients with mitral stenosis than in controls (2.9 +/- 1.5 versus 5.2 +/- 2.1; p < 0.001, and 11.2 +/- 5.6 versus 14.8 +/- 5.6; p = 0.011, respectively). In addition, a significant negative correlation was identified between the erythrocyte sedimentation rate and circulating CD4+CD25+ T-cell count (Spearman rho = -0.414; p = 0.006). No correlation was found between CD4+CD25+ T-cell count and clinical and echocardiographic parameters in patients with mitral stenosis.

CONCLUSION

A decrease in CD4+CD25+ T cell numbers in mitral stenosis patients might suggest a role for cellular autoimmunity in a smoldering rheumatic process.

Plasma cytokine levels in cardiac chambers of patients with mitral stenosis with congestive heart failure

To ascertain whether elevated levels of circulating proinflammatory cytokines in patients with advanced heart failure are due to congestive heart failure or due to cachexia or infection complicating heart failure, we measured prospectively plasma concentrations of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), interleukin 2 (IL-2), and interleukin-6 (IL-6) in 12 patients with mitral stenosis with moderate congestive heart failure, but not with cachexia or infection. Blood samples were obtained from the peripheral vein and right and left atria of the patients during percutaneous mitral valvuloplasty. Levels of TNF-alpha, IL-1 beta, IL-2, and IL-6 in the plasma form the peripheral vein and right and left atria of these patients were not elevated compared with those from the peripheral vein of a control group of 10 normal subjects. On the other hand, plasma levels of TNF-alpha but not IL-1 beta, IL-2 or IL-6, were elevated in 4 of 9 patients with congestive heart failure complicated with cachexia and/or infection. Our results suggest that proinflammatory cytokine levels are not elevated in congestive heart failure uncomplicated with cachexia or infection.

Corticosteroid and immune responses to cardiac surgery

Serum corticosteroid-binding globulin (CBG) and cortisol levels as well as subsets of circulating immunocompetent cells (ICCs) were measured during cardiac surgery. Closed heart surgery (closed mitral commissurotomy) resulted in an elevation of cortisol levels (up to 32 +/- 5 micrograms/dL by the end of the surgery) with no changes in CBG and ICC levels observed. Open heart surgery (open reconstruction of the mitral valve) in surface-induced hypothermia (without extracorporeal bypass) caused a dramatic drop in CBG activity (from 250 +/- 17 microM before the beginning of anesthesia to 198 +/- 15 microM by the end of cooling (just before cardiac arrest) and 158 +/- 13 microM after 30 min of reperfusion), whereas cortisol levels were only slightly elevated by the end of cooling, and a significant increase (up to 17 +/- 2 micrograms/dL) was observed only at the end of the surgery (60 min of reperfusion and warming). Similar to CBG, a significant decline in circulating ICC contents occurred in response to cooling and circulatory arrest.

The effect of pentoxifylline on the lung during cardiopulmonary bypass

Cardiopulmonary bypass (CPB) produces an inflammatory response due to the interaction of blood with a foreign body surface. The lungs are most affected by this inflammatory response. Pentoxifylline (PTX), a phosphodiesterase inhibitor and an inhibitor of leukocyte activation, is used to minimize damage in lungs where leukocytes play an important role. Twenty patients with mitral valve stenosis with planned mitral valve surgery were included in the study. The ten patients receiving pentoxifylline (PTX group) were administered 400 mg PTX orally TID for 3 days preoperatively and, following anesthetic induction, a 300 mg PTX infusion was given. The ten patients receiving no PTX were the control group (CT). Platelet and leukocyte counts, mean pulmonary arterial pressure (mPAP), pulmonary capillary wedge pressure (PCWP), cardiac index (CI), pulmonary vascular resistance (PVR), alveolar-arterial PO2 gradient (AaDO2) were measured just before and after CPB, and 2 h postoperatively. The number of the leukocytes increased in the blood samples drawn 15 min after CPB in both groups and 2 h postoperatively showed no statistical change. The number of platelets had decreased significantly at the end of the CPB in both groups and, 2 h postoperatively, there was a further decrease in the blood count in the control group (P < 0.05). There was no significant difference in either the preoperative or postoperative PAP, PAWP, and CI. Pulmonary vascular resistance increased in both groups following the CPB (CT, before: 136 +/- 44, after: 177 +/- 94 dyne. sec.cm-5; PTX, before: 151 +/- 82, after 182 +/- 43 dynes.sec.cm-5). Two hours postoperatively, a considerable increase continued in the control group (CT 219 +/- 170 dynes.sec. cm-5), while there was an insignificant increase in the PTX group (PTX 193 +/- 51 dynes.sec.cm-5) (P < 0.05). The alveolar-arterial PO2 gradient increased after the CPB in both groups but a moderate decrease was observed 2 h postoperatively. In lung biopsy specimens taken before and after the CPB, there was marked leukocyte sequestration in the control group, whereas the number of leukocytes was seen to be insignificant in the PTX group (P < 0.005). This dosage regimen of PTX inhibits the postoperative increase in PVR and greatly minimized leukocyte sequestration in the lung due to CPB.

[The microcirculatory function and immune status indices of patients with rheumatic heart defects combined with pulmonary hypertension]

Blood microcirculation and immunity were studied in 52 patients with rheumatic valve disease associated with pulmonary hypertension. The most pronounced changes were observed in patients with "active" pulmonary hypertension. Microcirculatory and immune disorders are likely to be pathogenetical factors aggravating prognosis of pulmonary hypertension.

Severe adult respiratory distress syndrome associated with transfusion of antileukocyte antibodies

The use of blood products is common in the period after cardiopulmonary bypass. A rare cause of adult respiratory distress syndrome is a reaction to antileukocyte antibodies. The plasma transfused may contain a potent leukocyte antibody that may cause severe problems in the intensive care unit.

Frequency of D8/17 B lymphocyte alloantigen in north Indian patients with rheumatic heart disease

Ninety patients with rheumatic heart disease and 50 age- and sex-matched healthy human volunteers representing a North Indian population were typed for the B cell alloantigen D8/17 using a monoclonal antibody and a single step immunofluorescence technique. This alloantigen was expressed in 66.44% patients with RHD as compared with 14% of the normal population. A high relative risk (RR = 11.13) indicated a strong association of D8/17 B cell alloantigen with rheumatic heart disease. Increase in the frequency of the marker was observed with increasing age up to the fifth decade (40-49 years) in these patients. However, the frequency of this alloantigen, in the present study, in North Indian patients with rheumatic heart disease is lower than that reported in the American population.

[Report of two operated cases with erythrocyte antibody]

Two operated cases with erythrocyte antibodies were reported. In the first case who required the second open heart operation for mitral stenosis, delayed hemolytic transfusion reaction by erythrocyte antibodies was recognized. The direct and indirect Coombs' tests were negative and the erythrocyte antibodies were not detected preoperatively. Massive blood transfusion during perioperative period precipitated secondary immunoreaction and reproduction of antibodies. An anti-c antibody and anti-E antibody were detected by the serologic studies on the 11th and 16th postoperative day. In the second case, stenotic mitral valve was replaced without homologous blood transfusion, because anti-C antibody was detected preoperatively. We believe that open heart operations without blood transfusion should be done, whenever possible, it should be kept in mind that delayed hemolytic transfusion reaction by erythrocyte antibody may occur after blood transfusion.

[Dynamics of the cellular and humoral immunity indices before and after closed commissurotomy]

The state of the cellular and humoral immunity was studied in patients with acquired valvular disease of rheumatic etiology who were subjected to closed commissurotomy. It was established that the patients whose postoperative course was complicated by a suppuration of the wound had low levels of T-lymphocytes, immunoglobulins in their peripheral blood in the postoperative period. A dramatic elevation of the content of immunoglobulins of all classes on the 7th day of the postoperative period is considered to be the evidence of the development of an infectious process.

Cellular immunity in rheumatic heart disease

Cellular immunity to non-specific antigens (PPD, Candida albicans, and streptococcal antigens) and mitogen (PHA) was investigated in patients with valvular heart disease of rheumatic origin. The result disclosed that lowered response in cellular immunity exists in these patients. The possible significance of this finding in occurrence of rheumatic activity was discussed.

Differences in antibody response to streptococcal antigens in children with rheumatic and non-rheumatic mitral valve disease

The usefulness of streptococcal antibody tests — anti-streptolysin O (ASO), anti-desoxyribonuclease B (anti-DNAse B), and anti-group A carbohydrate (A-antibody) — in differentiating rheumatic from non-rheumatic mitral disease was explored. Sera from 154 children with mitral disease were studied. Fifteen of 17 patients with chronic mitral insufficiency (MI) following acute rheumatic fever manifested persistence of elevated A-antibody levels following the decline of ASO and anti-DNAse B titers to normal 18-36 months after their acute illness. This antibody pattern was not observed among sera from 35 patients with congenital mitral valve deformities. Serologic study of 71 children with mitral disease of obscure etiology identified three groups: subgroup A includes those 12 who demonstrated the antibody pattern associated with rheumatic MI, while subgroup B is comprised of 39 children with normal A-antibody levels. Twenty patients (subgroup C) manifested evidence of recent streptococcal infection. These data suggest that the use of the A-antibody test in conjunction with other streptococcal antibody tests is of potential value in differentiating rheumatic from non-rheumatic mitral disease.