Mixed connective tissue disease

Mixed connective tissue disease

Mixed connective tissue disease (MCTD) is an overlapping syndrome with clinical signs of SLE, systemic scleroderma (SSD), and polymyositis. The predominant sex is female (8:1).


    • Constantly high titers of AT to nuclear ribonucleoproteins
    • Polyclonal hypergammaglobulinemia
    • T-suppressor defect
    • Presence of circulating immune complexes
    • Deposition of IgG, IgM and complement components in the walls of blood vessels and on the basement membranes of the renal glomeruli
    • Lymphocytic and plasmacytic tissue infiltration.


    • Proliferative lesion of the inner or middle lining of large and small blood vessels
    • This leads to narrowing of the lumen of the vessels.

Clinical picture

    • Lupus-like manifestations
    • Oligoarthritis (unlike SLE, can be erosive and lead to deformities)
    • Skin lesions:
    • Butterfly centrifugal erythema
    • discoid elements
    • alopecia
    • Kidney damage:
    • Proteinuria
    • Hematuria
    • Lack of progression of glomerulonephritis and development of renal failure (unlike SLE)
    • Fever
    • Lymphadenopathy
    • CNS damage (rare)
    • Polyserositis (not often).
    • Polymyositis-like manifestations
    • Proximal muscle weakness
    • Myalgia
    • Heliotrope edema within the eyes.
    • Scleroderma-like manifestations
    • Raynaud’s syndrome
    • Dense swelling of the hands and sclerodactyly
    • Telangiectasias, areas of hypo- and hyperpigmentation
    • Esophageal injury:
    • Decreased peristalsis in the distal sections
    • Weakness of the esophageal-gastric sphincter
    • Lung involvement (rare):
    • Pleurisy
    • Interstitial pneumonia
    • Secondary pulmonary hypertension.
    • Defeat SSS
    • Pericarditis
    • Myocarditis.
    • Sjögren’s syndrome.
    • Hashimdto’s thyroiditis.


    • Laboratory research
    • Anemia, leukopenia, increased ESR
    • Hypergammaglobulinemia
    • Antinuclear factor in high titer, mottled type of luminescence using immunofluorescence technique
    • AT to extractable nuclear Ag (i.e. to ribonucleoproteins, in particular, to the protein component of U, small nuclear ribonucleoprotein) in high titer
    • Anti-DNA antibodies typical of SLE are not found in MCTS
    • RF (often)
    • Increased concentration of muscle tissue enzymes in blood serum (CPK, less often – ACT, ALT, LDH)
    • Hypocomplementemia (rare)
    • X-ray examination
    • X-ray of bones – erosive changes are possible, more often in small joints of the hands
    • X-ray of the lungs
    • Signs of an effusion
    • Dissemination stimulated by interstitial changes is possible.
    • Special Studies
    • Echocardiography – possible signs of pericarditis
    • FEGDS – assessment of the condition of the esophagus
    • Measurement of the diffusion probability of the lungs by the difference in CO2 concentrations in the inhaled and exhaled air when using a mixture with a known pCO2.

Diagnostic Criteria—A definite diagnosis of CTD requires the presence of at least 4 of the following criteria:

  • severe myositis
  • Lung damage
  • Diffusion capacity of the lungs

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