In-vivo activation of complement in hereditary nephropathy

Membranoproliferative glomerulonephritis in a girl and her mother

A girl and her mother were diagnosed as having membranoproliferative glomerulonephritis (MPGN) type I. Microscopic hematuria and proteinuria presented at 9 years of age in the mother and at 14 years in the daughter. Both had persistent hypocomplementemia and were treated with steroids. When the mother was 40 years old, proteinuria was still continuing and creatinine clearance was 64.4 ml/min per 1.73 m(2). When the daughter was 15 years old, microscopic hematuria was still continuing. To our knowledge, familial cases of MPGN in two generations have not been reported in Japan.

Porcine membranoproliferative glomerulonephritis with intramembranous dense deposits (porcine dense deposit disease)

A membranoproliferative glomerulonephritis (MPGN) was diagnosed in 10 Yorkshire piglets, aged between 33 and 73 days, that had been submitted for routine autopsy. Matings of animals related to these piglets subsequently produced 15 offspring that had a membranoproliferative glomerulonephritis when examined at between 5 and 48 days of age. The principal light microscopic changes in all examined glomeruli of all affected piglets were thickening of the glomerular capillary walls and a conspicuous mesangial cell proliferation. The glomerular capillary walls of the affected piglets possessed a weak but distinct autofluorescence when stained with thioflavine T and a strong reactivity for complement factor 3 as demonstrated with immunohistochemical techniques. Ultrastructural examination revealed intramembranous dense deposits in the glomerular basement membranes of kidneys from all affected piglets. On the basis of the initial matings and the morphological observations, it is concluded that the described MPGN in Yorkshire piglets represents an inherited renal disease that is comparable to human MPGN type II-dense deposit disease.

Apparently changing patterns of inheritance in Alport's hereditary nephritis: genetic heterogeneity versus altered diagnostic criteria

With the use of more stringent diagnostic criteria, it has recently been shown that some large pedigrees of Alport's and non-Alport's hereditary nephritis fit sex-linked dominant inheritance (O'Neill et al. 1978). We have used similar diagnostic criteria and have studied a number of Michigan pedigrees in order to see if this hypothesis would be confirmed. We found one small pedigree which definitely shows male-to-male transmission, while one large pedigree is tentatively compatible with sex-linked dominant inheritance. Many of the other pedigrees suggested male-to-male transmission. This Michigan experience is compared to other published reports and found to be consistent, although a trend of fewer reports of male-to-male transmission is seen. We conclude that genetic heterogeneity of Alport's hereditary nephritis is likely.

Chronic hereditary nephritis. A clinicopathologic study of 23 new kindreds and review of the literature

Thirty-three patients with chronic hereditary nephritis, obtained from 23 unrelated families, were evaluated with respect to clinicopathologic features. Renal tissue was examined by light microscopy in 25 cases, immunofluorescence in 19 cases, and electron microscopy in 16 cases. The light microscopic findings varied, and foam cells were present in only four cases. Immunofluorescence was negative in all but four cases, and in these the immunomicroscopic pattern was compatible with the findings of end stage glomeruli and hyaline arteriolar sclerosis. Although electron microscopy uniformly showed marked thinning or splitting of the glomerular basement membrane, parallel splitting of the glomerular basement membrane with interposition of electron dense granular particles was seen in only eight cases. Association of glomerular basement membrane splitting with granular particles was observed in four of six patients with IgA nephropathy, in two patients with benign familial hematuria, and in a normal kidney donor. Eleven patients, seven men and four women, had chronic renal failure requiring dialysis. Of five patients who received renal allografts, three are alive, with post-transplant survival ranging from 24 to 70 months. The other two died of septicemia.

Serial complement studies in a patient with Goodpasture's syndrome treated with bilateral nephrectomy and renal transplantation

A young male patient with Goodpasture's syndrome was treated with bilateral nephrectomy and when antiglomerular basement membrane antibodies could no longer be detected he received a cadaveric renal homograft. Fifteen months later he is in good health and without signs of pulmonary disease. Renal function is satisfactory, and there are no findings indicating recurrence of the nephritis. Serial complement studies during the entire course revealed varying degrees of activity in the sequence in the different phases: a high degree of in vivo activation of complement was found in the period before the nephrectomy, there was a moderate degree of activation in the period between the nephrectomy and transplantation and, finally, there were no signs of activity in the system after transplantation. This investigation strongly suggests that the complement system is of definite pathogenetic significance in this human equivalent to experimental nephrotoxic nephritis.

The pathogenesis of arthritis associated with acute hepatitis-B surface antigen-positive hepatitis. Complement activation and characterization of circulating immune complexes

Circulating immune complexes were identified in cryoproteins isolated from serial samples of serum from six patients with acute viral hepatitis with and without arthritic symptoms. Cryoprecipitates were analyzed for the presence of hepatitis-B surface antigen (HBsAg) and hepatitis-B surface antibody (anti-HBs) by hemagglutination inhibition and hemagglutination. Complement components were detected by counter electrophoresis, and immunoglobulins were detected by gel diffusion. HBsAg, IgG, and IgM were identified in cryoprecipitates from all hepatitis patients, but were higher in concentration in patients with arthritis. Only cryoprecipitates from hepatitis patients with arthritis contained IgA and complement components C3, C4, and C5 as well as IgG and IgM, which disappear with resolution of the arthritis. The subtypes of IgG in these cryoprecipitates were predominantly the complement-fixing IgG1 and IgG3, HBsAg and anti-HBs were concentrated several-fold in the cryoprecipitates when compared to the serum concentration. Sequential studies in two patients demonstrated that the initial appearance of anti-HBs in the cryoprotein complex was associated with the detection in the complex of IgM suggesting a primary immune response to HBsAg. The C3 activator fragment (C3A) of the properdin complex was found in fresh serum obtained from three hepatitis patients with arthritis and not in uncomplicated hepatitis. The cryoprecipitable immune complexes from patients with arthritis converted C3PA in fresh normal sera to C3A in vitro whereas cryoprotein isolated from patients with uncomplicated hepatitis had no such effect. Thus, the transient appearance of circulating complement-fixing immune complexes in patients with the arthritis of acute hepatitis is associated with activation of both classical and alternate complement pathways and suggests that they play an important role in the pathogenesis of these serum sickness-like extrahepatic symptoms.

Complement system studies in systemic lupus erythematosus (SLE)

Complement system involvement has been studied in 16 patients with systemic lupus erythematosus (SLE). Circulating conversion products of C3 were observed in 4 cases. Low mean values of C4 and C3 were found, while C3 proactivator (properdin factor B) levels were low in only a few of the patients. The levels of C4, C3 and C3 proactivator were not lower in the 4 patients in whom C3 conversion products could be demonstrated than in the others. It is concluded that the low complement values found in SLE may be caused mainly by deficient synthesis. Signs of complement activation are in this patient material demonstrated early in the disease, and chiefly in patients not receiving immunosuppressive therapy.