MSK and dRTA: a puzzling association.

surface [1,4]. Although the actual frequency of Lyme disease-associated glomerulonephritis in humans is unknown as yet, it is our sense that this is most probably an underdiagnosed situation. An important factor that permits the diagnosis of the Lyme-associated glomerulonephritis to evade is the potentially chronic, remitting and relapsing course of the clinical manifestations of the causing infection. In view of the diagnostic obstacles and probably the low clinical suspicion for the search of Lyme disease, we believe that more cases of so-called ‘primary’ membranoproliferative glomerulonephritis (MPGN) or other glomerulonephritides might be associated with Lyme disease but are not diagnosed as such [5], a case which has also been documented in proteinuric dogs [6]. Regarding the treatment of Lyme nephritis, as long as the stimulation of the immune system caused by the infection seems to play a pivotal role in infection-associated glomerulonephritides, it would seem rational to treat such cases with a combination of antibiotics plus immunosuppressive therapy (corticosteroids, plasma exchange, interferon, monoclonal antibodies, etc.), in a way similar to the schemes used in the treatment of hepatitis C virusrelated glomerulonephritis. Although such a treatment has already been reported to be effective in a case of Lyme nephritis [3], the existing data are inconclusive.