Correlation of IL-6, IL-10, IL-18 and TNF-α Levels with Severity of Rheumatic Mitral Stenosis and Secondary Pulmonary Hypertension

Vimal Mehta, Pratishtha Mehra, Gaurav Tripathi, Jamal Yusuf, Bhawna Mahajan, Sanjay Tyagi

G. B. Pant Institute of Postgraduate Medical Education and Research, New Delhi, India

o Rheumatic heart disease (RHD) remains a major public health problem in

many parts of the world with an estimated world-wide prevalence of 33

million patients, of which about one-third cases (13.2 million) occur in India.

o The pathogenesis of acute rheumatic fever involves a complex network of

genetic, environmental and immunological interactions.

o The inflammatory response in acute rheumatic fever, on cardiac tissues is

induced by antigenic mimicry of the streptococcal protein M leading to an

abundant infiltration of CD4+ T cells.

o This leads to production of inflammatory cytokines (e.g., TNF-α, IL-2, and

IL-10), which potentiate the immune response in rheumatic fever.

Introduction

o Any evidence of clinical infection

o Moderate to severe mitral regurgitation/aortic stenosis or regurgitation

o ARF in last 6 months/any other CV disease or pulmonary disease

o Pregnancy and lactating mothers

o Any autoimmune or inflammatory condition/other significant illness

Exclusion Criteria

Conclusions o Chronic rheumatic mitral stenosis patients have increased IL-6, IL-10,

IL-18, TNF-α and hs-CRP levels suggesting a continuous ongoing

inflammatory activity even in clinically silent chronic phase.

o Further subjects having severe mitral stenosis had increased TNF-α levels

in comparison to subjects with mild to moderate mitral stenosis suggesting

its possible role in acceleration of rheumatic process.

A B

Hypothesis

o The severity of mitral stenosis in many RHD patients continues to progress

despite absence of recurrent rheumatic fever

o To determine the role of inflammatory cytokines in progression of rheumatic

valvular injury and its hemodynamic sequelae- pulmonary hypertension

Aims and Objectives

o To determine the serum levels of cytokines IL-6, IL-10, IL-18, TNF-α and

hs-CRP in peripheral blood of patients with chronic isolated rheumatic mitral

stenosis and compare it with controls

o To determine association of serum levels of IL-6, IL-10, IL-18, TNF-α and

hs-CRP with severity of rheumatic mitral stenosis & pulmonary hypertension

Inclusion and Exclusion Criteria

o Age >18 years

o Subjects with chronic rheumatic heart disease with mitral stenosis

diagnosed on echocardiography

Inclusion Criteria

Methodology Total subjects screened: 184

Screen failure: 12

Screen failure: 9

Rheumatic heart disease with isolated

mitral stenosis: 84 (Group A)

Age and gender matched controls: 79

(Group B)

Investigations done

ECG

ECHOCARDIOGRAPHY

Routine blood investigations

Serum IL-6, IL-10, IL-18, TNF-α, hs-CRP levels

Investigations done

ECG

ECHOCARDIOGRAPHY

Routine blood investigations

Serum IL-6, IL-10, IL-18, TNF-α, hs-CRP levels

Echocardiography Images of Study Subjects

Fig A: Normal mitral valve: short-axis

view showing thin mitral leaflets

Fig B: Normal mitral valve: M-mode

showing movement of AML and PML

Fig C: Mitral stenosis: short-axis view

showing thickened mitral leaflets

Fig D: Mitral stenosis: M-mode showing

PML excursion in anterior direction

Fig E: Mitral stenosis: AML doming and

spontaneous echo contrast

Fig F: Mitral stenosis: Diastolic

transmitral gradient of 43/26 mm Hg

A B C

D E F

Parameters Group A Group B P value

Number 84 79

Gender: Male

Female

22

62

31

48

NS

Age (years) 34.6 ± 10.6 30.0 ± 4.9 NS

Hb (gm/dL) 12.8 ± 1.8 13.1 ± 1.6 NS

TLC (per mm3) 4424 ± 1202 4892 ± 1486 NS

ESR 14.6 ± 2.9 12.4 ± 1.9 NS

Results o The presence or absence of atrial fibrillation did not have any impact on

cytokine levels.

o There was strong linear correlation between various cytokine levels.

Baseline Characteristics of Study Subjects

Rheumatic heart disease with mitral stenosis, n=84 (Group A)

Severity of mitral stenosis Presence or absence of pulmonary hypertension

Subgroup Aa

MVA ≤ 1 cm2

n= 59 (70%)

Subgroup Ab

MVA > 1 cm2

n= 25 (30%)

Subgroup Ac

RVSP ≥36 mm Hg

n= 47 (56%)

Subgroup Ad

RVSP <36 mm Hg

n= 37 (44%)

53 (63%) patients were in sinus rhythm and 31 (37%) patients had atrial fibrillation

IL-6 (pg/ml) IL-10 (pg/ml) hs-CRP (mg/l)

Group A 6.6 8.1 4.7

Group B 2.7 3.5 2.6

0

1

2

3

4

5

6

7

8

9

Group A

Group B P <0.001

P <0.001

P <0.001

P <0.001

Graph 1: Serum levels of IL-6, IL-10 and hs-CRP in Group A and B Graph 2: Serum levels of IL-18 and TNF-α in Group A and B

Echo Parameter (Gp A) Subgroup No. Mean SD

LA size (cm) Subgroup Aa

Subgroup Ab

59

25

4.5

4.3

0.52

0.30

MVA (cm2) Subgroup Aa

Subgroup Ab

59

25

0.8

1.3

0.18

0.17

Mean Gradient

(mm Hg)

Subgroup Aa

Subgroup Ab

59

25

18.6

7.9

6.5

1.9

Peak Gradient

(mm Hg)

Subgroup Aa

Subgroup Ab

59

25

28.4

12.4

7.5

2.1

RVSP (mm Hg) Subgroup Ac

Subgroup Ad

47

37

55.3

26.3

20.0

4.5

0

5

10

15

20

25

Subgroup Aa Subgroup Ab Subgroup Ac Subgroup Ad

5.6

6.9 6.8 6.2

8.3 7.7

8.7

7.4

20.7

7.5

20.2

22.9

3.7 4.3 4.8 4.7

IL-6 IL-10 TNF-α hs-CRP

Graph 3: IL-6, IL-10, TNF-α, hs-CRP levels

IL-18 (pg/ml) TNF-α (pg/ml)

Group A 136.3 21.2

Group B 47.9 5.3

0

20

40

60

80

100

120

140

160

Group A

Group B

P <0.001

P <0.001

Left atrial diameter 4.47 ± 0.52 cm

Mitral valve area 0.95 ± 0.28 cm2

Peak transmitral gradient 20.18 ± 7.56 mm Hg

Mean transmitral gradient 13.08 ± 6.57 mm Hg

Right ventricular systolic pressure 42.58 ± 20.88 mm Hg

Echocardiography Parameters of RHD Mitral Stenosis Group A

Subgroups of Rheumatic Heart Disease Patients

0

20

40

60

80

100

120

140

160

Subgroup Aa Subgroup Ab Subgroup Ac Subgroup Ad

146.3

112.3

145.3

124.7

IL-18

Graph 4: IL-18 levels in various subgroups

• CD4+ T cells are the major effectors of autoimmune

reactions in the heart tissue in RHD patients.

• IL-6 is a pro-inflammatory cytokine with role in ARF.

• IL-10 is produced by activated immune cells, esp.

monocytes/ macrophages and T cell subsets, and

regulates the functions of many different immune cells.

• IL-18 is a proinflammatory cytokine which belongs to

the IL-1 superfamily and produced mainly by

macrophages and stimulates various immune cell types.

• TNF-α is a proinflammatory cytokine that has been

associated with severity of different autoimmune and

inflammatory diseases.

#TNF-α:

P <0.0001 *IL-10:

P =0.02

P =NS

* *

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