A 58-year-old man complains of weakness, edema of the face, legs, and lumbar region, dyspnea, and wet cough. For many years he has been suffering from chronic obstructive pulmonary disease. Within the last 5 years he has been noting increased production of sputum that often is purulent. Objectively, his heart rate is80/min., blood pressure is 120/80 mm Hg. He has pale and dry skin with poor turgor and diffuse edema. Daily proteinuria is 6.6 g/L. In the blood:hypoalbumincmia, increased levels of «2-and 7-globulins, ESR is 50 mm/hour. Blood creatinine is 188 mcmol/L. Which is the correct diagnosis?