Detection of Human Cytomegalovirus-DNA in IgA Nephropathy

PD Dr. G.A. Müller, Eberhard-Karls-Universität, Medizinische Klinik und Poliklinik, Abteilung Innere Medizin III, D-W-7400 Tübingen 1 (FRG) Dear Sir, Although IgA nephropathy is a very common type of glomerulonephritis, its pathomechanisms are still an unresolved issue. Since the first description of mesangial staining of polyclonal antihuman cytomegalovirus (anti-HCMV) antibodies by Gregory et al. [1] several conflicting reports [2–5] about the presence of HCMV in kidneys and its role in the pathogenesis of this nephropathy were published. Serological analysis of humoral immune responses as well as staining of renal tissues with anti-HCM V monoclonal antibodies and also the use of in situ hybridization technique by Okamura et al. [4] were not able to solve this problem. For a further evaluation of the HCMV-DNA association with IgA nephropathy the polymerase chain reaction (PCR) and slot-blot hybridization assay were used to detect HCMV-DNA in renal biopsies of 10 patients with histologically proven IgA nephropathy in comparison to 9 normal controls and 7 patients with focal segmental glomerulosclerosis (FSGS). Cryostat sections of all biopsies were used for DNA extraction after proteinase K digestion. PCR amplification of a 147-bp DNA fragment of the immediate early gene of HCMV was performed in 32 cycles as described elsewhere [6]. 10-μl aliquots of the PCR product were fixed on nylon membranes using the slot-blot technique and cytomegalovirus-DNA was detected by hybridization with digoxigenin-labelled probes. In this assay the sensitivity for detecting HCMVDNA is down to 0.1 fg. 1 Supported by the Deutsche Forschungsgemeinschaft, DFG Mu 523/3–5 and the Alexander von Humboldt-Stiftung. Table 1. Detection of HCMV in renal tissue using (PCR) technique Diagnosis Number of biopsies analyzed positive IgA nephropathy 10 10 FSGS 7 0 Normal kidneys 9 3