Glomerulonephritis associated with complete deficiency of the fourth component of complement. Response to intravenous immunoglobulin

Intravenous immunoglobulin in the management of lupus nephritis

The occurrence of nephritis in patients with systemic lupus erythematosus is associated with increased morbidity and mortality. The pathogenesis of lupus nephritis is complex, involving innate and adaptive cellular and humoral immune responses. Autoantibodies in particular have been shown to be critical in the initiation and progression of renal injury, via interactions with both Fc-receptors and complement. One approach in the management of patients with lupus nephritis has been the use of intravenous immunoglobulin. This therapy has shown benefit in the setting of many forms of autoantibody-mediated injury; however, the mechanisms of efficacy are not fully understood. In this paper, the data supporting the use of immunoglobulin therapy in lupus nephritis will be evaluated. In addition, the potential mechanisms of action will be discussed with respect to the known involvement of complement and Fc-receptors in the kidney parenchyma. Results are provocative and warrant additional clinical trials.

Familial C4B deficiency and immune complex glomerulonephritis

Homozygous complement C4B deficiency is described in a Southern European young female patient with Membranoproliferative Glomerulonephritis (MPGN) type III characterized by renal biopsies with strong complement C4 and IgG deposits. Low C4 levels were independent of clinical evolution or type of immunosuppression and were found in three other family members without renal disease or infections. HLA typing revealed that the patient has homozygous A*02, Cw*06, B*50 at the class I region, and DRB1*08 and DQB1*03 at the class II region. Genotypic and phenotypic studies demonstrated that the patient has homozygous monomodular RCCX in the HLA class III region, with single long C4A genes coding for C4A3 and complete C4B deficiency. Her father, mother, son and niece have heterozygous C4B deficiency. The patient's deceased brother had a history of Henoch-Schönlein Purpura (HSP), an immune complex-mediated proliferative glomerulonephritis. These findings challenge the putative pathophysiological roles of C4A and C4B and underscore the need to perform functional assays, C4 allotyping and genotyping on patients with persistently low serum levels of a classical pathway complement component and glomerulopathy associated with immune deposits.

Renal disease associated with inherited disorders of the complement system

The human complement system is vital for host defense and plays a role in a number of inflammatory disorders. Inherited deficiency or dysfunction of most of the individual complement components occurs uncommonly. The phenotype displayed by such patients varies with the specific component deficiency and ranges from recurrent infections to autoimmune diseases. Most of the latter are associated with glomerulonephritis. The onset of severe lupus erythematosus in a young child, with prominent cutaneous and renal manifestations, especially if a similar disorder is present in another family member, is a clue to the presence of a complement component deficiency. The distinguishing of acquired deficiencies from inherited deficiencies in complement components is sometimes difficult and may require sophisticated laboratory testing.

The efficiency of intraperitoneal high-dose immunoglobulin in experimental nephrotic syndrome

Although it has been reported that high-dose immunoglobulin has beneficial effects in chronic glomerulonephritis, it is not known whether it is effective in the treatment of idiopathic nephrotic syndrome. We have investigated the effects of intraperitoneal immunoglobulin in adriamycin-induced nephrotic syndrome. Adriamycin (2 mg kg(-1) per dose) was given intravenously to sixteen Wistar albino rats (eight control and eight treatment rats) on day 1 and at week 3. At week 5 intraperitoneal immunoglobulin (1 g kg(-1) per dose) was given to the treatment group on two consecutive days whereas the control group received intraperitoneal saline solution. In both treatment and control groups urinary protein excretion was significantly elevated after administration of adriamycin (P=0.018). Urinary protein excretion, serum albumin, and triglyceride levels in the two groups were not significantly different after 5, 8, 12, and 16 weeks. Serum creatinine levels were higher and creatinine clearance was significantly lower in the control group in week 16 (P=0.001 and P=0.049, respectively). Glomerular sclerosis index was significantly lower in the treatment group (P=0.012). Although intraperitoneal high-dose immunoglobulin did not reverse biochemical results, it is encouraging that glomerular sclerosis index was significantly lower in the treatment group.

Intravenous immunoglobulin and the kidney—a two-edged sword

OBJECTIVES

To review the literature on the use and efficacy of intravenous immunoglobulin (IVIG) in glomerulonephritis and to evaluate the nephrotoxic effect of IVIG.

METHODS

A structured literature search of articles published on the efficacy of IVIG in the treatment of nephritis between 1985 and 2003 was conducted. All articles dealing with lupus nephritis, IgA nephropathy, Henoch Schonlein purpura, antineutrophil cytoplasmic antibodies (ANCA) associated vasculitis, primary membranous glomerulonephritis, and primary chronic nephritis were reviewed. The same literature search was conducted for the nephrotoxic effects of IVIG. Two groups of patients were defined: (a) a group of patients with IVIG nephrotoxic effect published as case reports, and (b) a group of patients whose data were collected by the Food and Drug Administration (FDA). All existing data of both groups were pooled and compared.

RESULTS

One hundred six patients with lupus nephritis were treated with IVIG. In most reports proteinuria, nephrotic syndrome, and values of creatinine clearance were improved. In 3 cases improvement in World Health Organization (WHO) class was noted, and in 2 cases a reduction of immune deposits was demonstrated. In the other forms of autoimmune nephropathy, although the number of reported cases was small, improvement was noted in most patients. Thirty-two reports entailing 78 patients with IVIG-induced nephrotoxicity were found and their data were compared with those of 88 patients reported to the FDA. No specific differences were noted between the 2 groups of patients, as their age and indications for using IVIG were similar. Most of the patients who developed renal toxicity (72% in the literature and 90% in the FDA group) received sucrose -containing IVIG products. A high percentage of patients (31% in the literature and 40% in the FDA group) required hemodialysis. Mortality occurred in 10 and 15%, respectively. Renal histology done in a minority of the cases demonstrated vacuolization and swelling of the proximal tubules consistent with osmotic injury.

CONCLUSIONS

On one hand, there are encouraging reports on the efficacy of IVIG in different types of glomerulonephritis (mainly lupus nephritis) resistant to conventional therapy, but the exact success rate and clinical indications remain undetermined. On the other hand, IVIG and the kidney is a two-edged sword, since nephrotoxicity can be a serious rare complication of IVIG therapy. Products containing sucrose as a stabilizer are mainly associated with such injury through the mechanism of osmotic nephrosis. Preexisting renal disease, volume depletion, and old age are risk factors for such toxicity.

Transgenic expression of a soluble complement inhibitor protects against renal disease and promotes survival in MRL/lpr mice

To investigate the role of complement in lupus nephritis, we used MRL/lpr mice and a transgene overexpressing a soluble complement regulator, soluble CR1-related gene/protein y (sCrry), both systemically and in kidney. Production of sCrry in sera led to significant complement inhibition in Crry-transgenic mice relative to littermate transgene negative controls. This complement inhibition with sCrry conferred a survival advantage to MRL/lpr mice. In a total of 154 animals, 42.5% transgene-negative animals had impaired renal function (blood urea nitrogen > 50 mg/dl) compared with 16.4% mice with the sCrry-producing transgene (p < 0.001). In those animals that died spontaneously, MRL/lpr mice with the sCrry-producing transgene did not die of renal failure, while those without the transgene did (blood urea nitrogen values of 46.6 +/- 9 and 122 +/- 29 mg/dl in transgene-positive and transgene-negative animals, respectively; p < 0.001). Albuminuria was reduced in those transgenic animals in which sCrry expression was maximally stimulated (urinary albumin/creatinine = 12.4 +/- 4.3 and 36.9 +/- 7.7 in transgene-positive and transgene-negative animals, respectively; p < 0.001). As expected in the setting of chronic complement inhibition, there was less C3 deposition in glomeruli of sCrry-producing transgenic mice compared with transgene-negative animals. In contrast, there was no effect on glomerular IgG deposition, levels of anti-dsDNA Ab and rheumatoid factor, or spleen weights between the two groups. Thus, long-term complement inhibition reduces renal disease in MRL/lpr mice, which translates into improved survival. MRL/lpr mice in which complement is inhibited still have spontaneous mortality, yet this is not from renal disease.

Intravenous immunoglobulin treatment of lupus nephritis

OBJECTIVE

To evaluate the clinical response of treatment-resistant membranous and membranoproliferative lupus nephritis to intravenous immunoglobulin (IVIg).

METHODS

Seven lupus nephritis patients who failed to respond to at least prednisone and cyclophosphamide were studied. A kidney biopsy showing either membranous or membranoproliferative glomerulonephritis was available in six patients. They were treated with six courses (patients 1 and 2) or 1 or 2 courses (patients 3 through 7) of high-dose IVIg. For patients 3 through 7, the plasma levels of albumin, total cholesterol, urea, creatinine, dsDNA antibody titers, and daily proteinuria were measured just before the IVIg therapy, immediately on completion, and 6 months later.

RESULTS

All seven patients had a beneficial response to IVIg. In patient 1, decrease in proteinuria was evident 2 weeks after IVIg was started, nephrotic syndrome gradually disappeared, and she had no proteinuria in 3 years' follow-up. Decline in proteinuria was evident in patient 2 after the 4th IVIg course, but proteinuria reached the pretreatment level 4 months after the therapy ended. In patients 3 through 7, the mean daily proteinuria before IVIg (5.3 +/- 2.1 g) decreased after 1 or 2 IVIg courses (3.3 +/- 1.4 g), and further decreased when measured 6 months later (2.1 +/- 1.3 g). Similarly, the plasma cholesterol level decreased while the plasma albumin level increased after IVIg.

CONCLUSIONS

IVIg might be effective in treatment-resistant membranous or membranoproliferative lupus nephritis. Future studies should concentrate on determining the preferred treatment protocol of IVIg for the various classes of lupus nephritis.

A study of 20 SLE patients with intravenous immunoglobulin--clinical and serologic response

OBJECTIVE

To test the clinical response of systemic lupus erythematosus (SLE) patients to intravenous immunoglobulins (IVIg), and whether the clinical response of IVIg treatment in SLE is accompanied by modification of SLE-associated autoantibodies/antibodies (Abs) and complement levels.

METHODS

Twenty SLE patients were treated with high-dose (2 g/kg) IVIg monthly, in a 5-d schedule. Each patient received between 1-8 treatment courses. They were evaluated for the clinical response, Systemic Lupus Activity Measure (SLAM) score before and after IVIg, levels of antinuclear antibody (ANA), dsDNA (double-stranded DNA), SS-A or SS-B, ENA (extractable nuclear antigens), C3 and C4 levels before and after the treatment, and before and after each treatment course.

RESULTS

A beneficial clinical response following IVIg treatment was noted in 17 out of 20 patients (85%). Few clinical manifestations responded more to treatment: arthritis, fever, thrombocytopenia, and neuropsychiatric lupus. In 9 patients evaluated before and after IVIg, mean SLAM score decreased from 19. 3+/-4.7 to 4+/-2.9 (P<0.0001). There was a tendency towards abnormal levels of complement and Abs before IVIg courses among the treatment responders compared with the non-responders, and similarly the former tended to have normalization of their abnormal levels more than the latter. These differences were found statistically significant only with respect to C4 and SS-A or SS-B levels before IVIg courses.

CONCLUSION

IVIg has a high response rate among SLE patients. A combination of clinical manifestations, Abs and complement levels may aid in the future in predicting who among SLE patients will benefit more from IVIg treatment.

[Polyvalent intravenous immunoglobulins in systemic lupus]

PURPOSE

To evaluate intravenous immunoglobulins (IVIG) treatment, which is immunomodulatory but not immunosuppressive, in SLE.

MAIN ISSUES

IVIG indications in SLE could be categorized as already validated as for chronic polyradiculoneuropathy or thrombocytopenia; failure of classical treatment in threatening active disease; undetermined manifestation as reactive hemophagocytic syndrome which could be both disease-specific or iatrogenic, infection-related. To date, no published study has firmly established the efficacy of IVIG in SLE.

CONCLUSION

IVIG therapy in SLE should be evaluated in prospective trials.

Immune complex glomerulonephritis in C4- and C3-deficient mice

In this study, we examined the roles of C4 and C3 in immune complex glomerulonephritis by actively immunizing C4-deficient (C4 -/-), C3 deficient (C3 -/-) and wild-type mice with apoferritin. Wild-type animals with an intact complement system produced anti-apoferritin IgG and IgM antibodies, and developed mesangial proliferative glomerulonephritis characterized by hypercellularity, matrix expansion, deposition of IgG, IgM, IgA and C3, and the presence of electron dense deposits. In the majority of animals, the peripheral capillaries also contained IgG, C3 and subendothelial and subepithelial electron dense deposits. In contrast to wild-type animals, all apoferritin-immunized C4 -/- and C3 -/- mice had serum cryoprecipitates containing polyclonal IgM and the variable presence of polyclonal IgG. These animals also developed immune complex glomerulonephritis, but their disease manifestations were distinctly different from that of their wild-type littermates. In apoferritin-immunized C4 -/- and C3 -/- mice, IgG was either absent or present in reduced quantities in glomeruli, yet IgM and IgA were present in greater intensity in glomeruli. Capillary wall IgG deposits were absent in all C4 -/- and C3 -/- animals. C4 -/- animals also had significant glomerular C3 deposition, hypercellularity and neutrophil infiltration, which were not present in C3 -/- animals. These results illustrate the complex interplay between the effects of complement to process immune complexes and to lead to inflammation and tissue injury.

The phenotype of SLE associated with complete deficiency of complement isotype C4A

Complete deficiency of the complement C4A isotype is a known genetic risk factor for systemic lupus erythematosus (SLE). The disease phenotype of C4A-deficient patients has never been defined. Among 200 patients with SLE from five centers, 18 (9%) with C4A deficiency were identified. These individuals were compared to those who were C4A replete with regard to a series of clinical and serologic features. The only significant differences between the two groups were in the presence of renal disease (C4A deficient, 11%; C4A replete, 46%; P < 0.006) and a decrease in the serum concentrations of C3 (C4A deficient, 11%; C4A replete, 35%; P < 0.04). There was also a trend for the C4A-deficient individuals to have milder disease. In light of the tendency for C4A-deficient individuals to have lower serum concentrations of C4, it is important that such patients not be subjected to overly aggressive efforts to "normalize" their C4 levels.

Clinical relevance of Fc gamma receptor polymorphisms

Human IgG receptors are very heterogeneous and we currently distinguish three Fc gamma receptor classes specifying at least 12 receptor isoforms. On top of this complexity, Fc gamma R are further found to differ between different individuals. Polymorphisms have been identified for all three Fc gamma R classes. The best-studied ones represent allelic variation of Fc gamma RIIa (CD32) and Fc gamma RIIIb (CD16). The Fc gamma RIIa polymorphism is now considered to be a heritable risk factor for autoimmune and infectious diseases, and support for a relevant role of the IIIb polymorphism has also been obtained. A detailed analysis of the exact contribution of each of these Fc gamma R polymorphisms in relation to previously implicated risk factors should unravel the pathophysiological importance of Fc gamma R polymorphisms in the near future.