Right atrial myxoma: a potential accelerator of pulmonary hypertension in the course of systemic sclerosis. The role of interleukin-6

Pulmonary arterial hypertension (PAH) is a rare disease. The prognosis of PAH is usually poor and it is the worst in the case of forms associated with connective tissue diseases. In recent years we have observed an improvement in the effects of PAH treatment.
Systemic sclerosis (SS) is an autoimmune disease. The clinical symptoms include generalized hardening of the skin, extensive lesions in visceral organs, including the gastrointestinal tract, heart, lungs and kidneys. The CREST syndrome (calcinosis, Raynaud, oesophageal dysmotility, sclerodactyly and telangiectasia (5–12%)) develops pulmonary arterial hypertension associated with specific diseases (A-PAH) secondary to interstitial pulmonary fibrosis or isolated pulmonary arteriopathy, and pulmonary hypertension (PH) associated with left heart involvement [1–3].
Myxoma is a benign neoplasm of the heart and constitutes approximately 50% of all benign neoplasms of the heart [4]. In approximately 75–80% of cases a myxoma is located in the left atrium (LA), in 20–25% of cases in the right one. The clinical symptoms associated with the myxoma can be divided to systemic ones and resulting from the presence of the tumour in heart chambers. Systemic symptoms include decreased body mass, elevated body temperature, skin lesions, musculo-articular pain, increased C-reactive protein (CRP) and immunoglobulin levels [5–7]. Presence of antinuclear antibodies and the rheumatoid factor can be observed as well. In the medical literature these symptoms are referred to as a myxoma syndrome [8].
Cardiovascular symptoms result from disturbances in the heart function caused by the tumour. Systemic symptoms and abnormalities on laboratory tests observed in myxoma are similar to those observed in inflammatory diseases, including those of autoimmune origin, such as SS. It is presupposed that interleukin 6 (IL-6) is mainly responsible for this fact. Interleukin-6 is a cytokine modifying the inflammatory response by affecting the differentiation of T lymphocytes and transformation of B lymphocytes to plasmocytes, and stimulating the liver to produce acute-phase proteins. Hirano et al. found out that myxoma cells produce IL-6 [9]. An increased concentration of this cytokine is observed in 80% of patients with diagnosed myxoma. Interleukin-6 cytokine concentration is currently a valuable marker in the diagnostic process and post-operative monitoring of the tumour [10].
In PAH, cytokines such as IL-1, IL-6,...


View full text...