SUMMARYComplement activation in 73 renal transplant biopsies was investigated by indirect immunoperoxidasc staining using MoAbs rcacEivc with complement-splil products. Intense deposition of complement fragments C4d and C3d in pcritubulur capillaries, indicating activation of the classical pathway, eould be detected in the majority of transplanted kidneys wilh cell-mediated rejections. Abundant deposition of complement-split products was observed in 22 early biop.sies from patients with high 'immunological risk* (i.e. previous, rejected transplants and/or circulating antibodies against HLA-antigens). Despite negative results in the crossmatch before transplantation and paueity of immunoglobulins in transplant biopsies, antibodies directed against endothelial eell antigens should be eonsidered as a possible cause of elassical complement activation.

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Amyloidosis due to the retention of β₂-microgιobulin (β₂-MG) is a frequent complication of hemodialysis (HD). Significant amounts of β₂-MG can be removed from the body by highly permeable HD membranes, whereas conventional low-flux membranes are impermeable for the molecule. In a prospective and controlled study we investigated whether high-flux HD could delay the onset of dialysis-related amyloidosis (DRA). Twenty patients treated with cuprophane low-flux HD membranes were matched for age and previous time on HD either to continue their HD regimen or to receive HD treatment with high-flux polysulfone membranes. For 6 years each patient was examined for manifestations of DRA once a year or upon individual needs, additionally, serum β₂-MG levels were monitored. After 6 years of follow-up no clinical signs of DRA were found in any of the patients dialyzed with high-flux polysulfone membranes, whereas 8/10 of the conventionally dialyzed patients had CTS and/or osteoarticular lesions. Serum levels of β₂-MG were significantly reduced in patients treated with high-flux polysulfone membranes.

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A 42-year-old woman presented with oral and labial erosions, conjunctivitis, facial rash and lichenoid erythematous papules on the trunk. Paraneoplastic pemphigus (PNP) was suspected, and a search for a neoplasm revealed an intra-abdominal Castleman tumour sized 7 x 5 x 6 cm. After removal of the Castleman tumour, the skin and mucosal inflammation gradually subsided over the next 12 months. However, due to irreversible pulmonary involvement the patient died of intractable respiratory distress 2 years after the onset of the disease. Systemic corticosteroids, azathioprine, cyclophosphamide, high-dose intravenous immunoglobulins and thalidomide were ineffective. The diagnosis of PNP was confirmed by keratinocyte antigen immunoprecipitation with the patient's serum.