Essential Mixed Cryoglobulinemia and IgA Nephropathyan Infrequent Association

Luis Orte, Servicio de Nefrologia, Hospital Ramón y Cajal, Crtra. Colmenar, Km 9.100, E-28034 Madrid (Spain) Dear Sir, Essential mixed cryoglobulinemia (EMC) is an infrequent disease grouped together with hypersensitivity vasculitis [1]. Glomeru-lar involvement is present in 50% of cases, morphologically identified as a membrano-proliferative glomerulonephritis, and related to the presence of mixed type IgG-IgM serum cryoglobulins, less frequently with the IgG-IgG and IgG-IgA complexes [2-5]. On reviewing the literature we have found only one case of EMC type III IgG-IgA associated with IgA nephropathy (IgA N) [6]. In this paper, we describe the first case of EMC type II EgG-IgM with IgA N as renal involvement. Our patient was a 58-year-old female with a 10-year history of arthralgia and cutaneous lesions. She was referred to our service because of urinary sediment changes; over the preceding 6 months she had experienced dark urine, and in the 3 months prior to admission arterial hypertension and general malaise, weakness and weight loss. The only noteworthy findings in the physical examination were systolic hypertension (180/90 mm Hg), mucocutaneous pallor and residual hyperpig-mentation in both lower limbs. She had severe normochromic normocytic anemia (Hb 7.9 g/ dl; Ht 23.9%), proteinuria (0.85 mg/min), microscopic hematuria, and a mild renal insufficiency (blood urea 83 mg/dl and crea-tinine 1.7 mg/dl). Serum proteins were normal, with an isolated increase of IgG: 2,210 mg/dl (normal 810-1,690); antinuclear antibodies and HbsAg were negative; C4: 8.3 mg/dl (normal 10^10); CH50: 47 U/ml (normal 150-250). Rheumatoid factor was positive; Latex was 102 IU/ml (normal 0^10). Cryoglobulins were positive in two samples; immunoelectrophoresis revealed the presence of IgM-kappa and polyclonal IgG in the cryoprecipitate. No pathological findings were detected on chest, gastrointestinal and osseous X-ray studies, abdominal echo-graphy, and bone marrow aspirate and biopsy. Renal biopsy showed glomerular mesan-gial matrix expansion with exudative lesions, and isolated interstitial foci of inflammatory mononuclear cells; direct immunofluores-cence revealed generalized and diffuse deposits of IgA( ) and C3(+) in the mesan-gium. All findings are compatible with me-sangial glomerulonephritis with IgA deposits. IgA N has been described as idiopathic or in association with a large number of systemic diseases [7]. Serum IgA is elevated in 50% of cases. Positive cryoglobulins in their serum are detected less frequently (15%), but associated with normal serum complement levels and