Ulrich H. Rudofsky

MULTIPLEX INHERITANCE OF COMPONENT PHENOTYPES IN A MURINE MODEL OF LUPUS

Abstract. We analyzed the linkage of GN and a wide spectrum of serological phenotypes associated with systemic lupus erythematosus in a (NZM2410 × C57BL/6)F2 cross. Some phenotypes, such as glomerulonephritis (GN) and anti-chromatin IgG antibody production, were more penetrant in females, but others, such as anti-dsDNA antibody production, did not show a gender bias. These results suggest that gender bias affects only a subset of SLE-component phenotypes, and that NZM2410 can be used to dissect the genetic basis of this phenomenon. Genome scanning linked six chromosomal intervals with the expression of one or more component phenotypes. These loci included two Sle loci previously identified in an (NZM2410 × B6)F1× NZM2410 backcross, loci identified by others in the NZB/W model. Our analysis also suggested two new intervals on chromosomes (Chrs.) 10 and 11. Detailed analysis of the segregation of different phenotypes within these intervals suggests that they encompass more than one susceptibility locus. This clustering has been a common finding in several murine polygenic traits. Each of NZM2410 susceptibility loci can be aligned with a specific genetic pathways contributing to SLE pathogenesis on the basis of the spectrum of component phenotypes expressed.

Plasma Renin Activity Decrease Precedes Spontaneous Focal Glomerular Sclerosis in Aging Rats

An association between the activity of the renin-angiotensin system and the development of spontaneous focal glomerular sclerosis (FGS) in rats has been observed: the onset is preceded by a decrease in plasma renin activity (PRA). This observation was facilitated by the use of Fawn-hooded rats, which develop spontaneous FGS at an early age. Male Fawn-hooded rats develop severe FGS as early as 3 months of age. Male Wistar rats do not develop similar lesions until after 1 year of age. Correspondingly the PRA drops much sooner in Fawn-hooded than in Wistar rats. The low PRA appears to be due to low plasma renin rather than a limitation of the renin substrate, angiotensinogen, which appears to be present in the Fawn-hooded plasma in nonlimiting quantities. In the FH male rats renin content of the kidney drops only after severe glomerular pathology is evident, implying that the low PRA may be due to a decrease in renin secretion by the chromaffin cells of the juxtaglomerular apparatus.

The significance of a positive cutaneous immunofluorescence test in systemic lupus erythematosus

Direct cutaneous immunofluorescence microscopical examination of uninvolved skin is an important diagnostic test in systemic lupus erythematosus. Its prognostic significance is undetermined. In twenty‐four patients there was an increased incidence of leukopenia, hypocomplementaemia, and LE cells in patients with positive skin immunofluorescence. Positive cutaneous immunofluorescence of uninvolved skin was correlated with the most severe forms of lupus renal disease, membranous glomerulonephritis, and diffuse proliferative glomerulonephritis.

Studies on the pathogenesis of experimental autoimmune renal tubulointerstitial disease in guinea pigs: 1. Inhibition of tissue injury in leukocyte-depleted passive transfer recipients☆

Abstract Renal tubulointerstitial disease (RTD) in guinea pigs is passively transferred to unmanipulated recipients by autoantibody to renal tubular basement membrane. The present experiments show that such tissue injury could not be induced in recipients depleted of radiosensitive circulating leukocytes before or 1 day after injection of antibody. Radioresistant phagocytic mononuclear cells, characteristic of RTD lesions, did not accumulate in the target organ in the absence of radiosensitive cells. When lethally irradiated recipients were reconstituted by bone marrow grafts and then given antibody, they developed RTD indistinguishable from that seen in unirradiated passive transfer recipients. There observations indicate that the initial accumulation of radiosensitive leukocytes in the target tissue is mediated by autoantibody and complement, and that progression of tissue damage depends to some extent on radioresistant mononuclear cells. Direct injury of renal tubules by complement and autoantibody was not observed.

Studies on the pathogenesis of experimental autoimmune renal tubulointerstitial disease in guinea pigs: II. Passive transfer of renal lesions by anti-tubular basement membrane autoantibody and nonimmune bone marrow cells to leukocyte-depleted recipients☆

Abstract Renal tubulointerstitial disease (RTD) in guinea pigs is induced by anti-tubular basement membrane (TBM) antibodies, complement, and radiosensitive mononuclear cells. The present experiments show that the bone marrow is the source of the initial cellular infiltrate. Groups of normal and irradiated guinea pigs were passively immunized to TBM; in addition, some of the leukocyte-depleted passive transfer recipients were injected with bone marrow cells from unimmunized donors. By day 6–8 RTD had occurred in 36 of 36 unmanipulated recipients, in none of 45 depleted animals, and in 18 of 25 given a combination of marrow cells and antibody. Under similar conditions, irradiated marrow cells or viable cells from thymus, spleen or lymph node did not elicit the accumulation of mononuclear cells in the renal cortex. Hence, mononuclear cells derived from the bone marrow play a major role in the pathogenesis.

Spontaneous and induced autoantibodies to renal and nonrenal basement membranes in mice

Abstract (NZB × NZW)F1 hybrid mice ( B W ) with lupus nephritis have, in rare instances, linear deposits of IgG on the renal tubular basement membrane (TBM). We have established that at least in one such unusual case this deposit is anti-TBM autoantibody. These spontaneously formed autoantibodies reacted with iso-, allo-, and xenogeneic TBM, but they were organ specific. Antibasement membrane autoantibodies were induced experimentally with xenogeneic TBM. Male B W , NZB, and random-bred mice immunized with rabbit TBM developed autoantibodies which reacted in vitro with TBM, glomerular basement membrane, lung basement membranes, and the basement membranes of seminiferous tubules. By contrast, in vivo deposition of IgG was seen in kidneys and testes but not in lungs. Despite the early presence of circulating autoantibodies (Day 8), renal tubulointerstitial lesions were not seen until Days 42 to 59 in 40 of 65 mice. The histopathologic involvement ranged from focal mononuclear cell infiltrates in the interstitium to severe disruption of tubules and TBM. Multinucleated giant cells were seen occasionally. IgG deposits were a mixture of complement- and noncomplement-fixing subclasses, but C3 was not readily detectable on GBM or TBM. C5+ and C5− strains developed similar renal lesions. By analogy with other models of autoimmune renal tubulointerstitial diseases, the lesions in mice may be caused by anti-TBM autoantibodies, but other undetermined pathogenetic mechanisms may also play a role.

Analysis of lead effects on in vivo antibody-mediated immunity in several mouse strains

The effect of administration of lead acetate (10 mM in the drinking water) for 8 weeks on the in vivo sheep red blood cell (SRBC) specific plaque-forming cell (PFC) responses of inbred A, BALB/c, C57Bl/6, DBA/1, SJL, and NZW/NZB F1 mice and outbred CFW mice was examined to determine if lead was immunomodulatory in a genetically related manner. Lead did not suppress the SRBC-specific PFC/10(6) splenocytes or PFC/spleen response in any mouse strain when compared to the responses of strain-matched control mice. In addition, 10 mM lead-treated BALB/c mice manifested augmented PFC/10(6) splenocytes (17%; p less than .05) but unchanged PFC/spleen responses. Correspondingly, serum concentrations of SRBC-specific antibody (measured by radioimmunoassay) and serum immunoglobulin G, M, or A isotypes were also unchanged by lead acetate treatment in all tested mouse strains. There were no observable lead-related histopathological changes or deposition of immune complexes or antibasement membrane antibody in the kidneys of treated mice. Further, splenocytes from lead-treated, SRBC-immunized mice cultured with T-independent antigens (TNP-LPS, TNP-Ficoll) or with a T-dependent antigen (SRBC) exhibited direct and indirect specific PFC responses that were unchanged from those of control mice. The H-2K/D haplotypes of the outbred CFW mice were determined by microcytotoxicity to include r, q, u, and s. These results suggest that lead acetate (10 mM) administered po for 8 weeks does not suppress the primary direct humoral immune response to SRBC in inbred and outbred mice of several H-2 haplotypes (k/d; d; b; q; d,z; s; r; and u).

Experimental autoimmune antiglomerular basement membrane antibody-induced glomerulonephritis. I. The effects of injecting sheep with human, homologous or autologous lung basement membranes and complete Freund's adjuvant.

We compared the effects of injecting human, homologous or autologous lung basement membrane (LBM) and complete Freunds adjuvant into 6-month-old sheep and injecting the same antigens into guinea pigs. All sheep receiving human LBM died of antiglomerular basement membrane (GBM) nephritis by Day 126. They had autoantibodies to antigenic determinants shared by fetal or adult sheep and human LBM and GBM and certain nonvascular basement membranes, but these autoantibodies did not localize in the lung in vivo or cause lung hemorrhages. No sheep injected with homologous or autologous LBM had any evidence of anti-GBM autoantibodies or nephritis or specific lung lesions. Their kidneys are indistinguishable by histologic, immunohistologic, and functional studies from kidneys of age-matched controls. Thus, sheep are very tolerant to their own LBM. Although all guinea pigs developed anti-GBM autoantibodies, they did not get anti-GBM nephritis or specific lung lesions. A hypothesis for the pathogenesis of Goodpastures syndrome is presented.

HLA and survival in lung cancer.

HLA A and B antigens were determined in a study of 125 patients with lung cancer. Differences between antigen frequencies in cancer and control populations were determined by chi 2 analysis or Fishers exact test. Survival data were analyzed using the Cox model for censored data. Cancer patients had an increased frequency of the antigen Aw33 (relative risk = 10.5, P less than 0.016). The Cox model (D. R. Cox, J. R. Stat. Soc. B, 34, 187, 1972) indicated that four covariates had a significant effect on mean survival time independently: the presence of A3 (P less than 0.005) and of Aw33 (P less than 0.05) increased mean survival time of the cancer population; patients with anaplastic carcinoma and stage three of any histological type of cancer had a decreased mean survival time. The determination of HLA phenotypes, cancer type, and the stage of the disease can provide the expected mean survival time of any particular patient. This could be of importance for evaluating prognosis. The effect of Aw33 and A3 on survival time may be related to HLA closely linked genes, possibly coding for resistance to the disease.

Experimental neonatal syphilis in a susceptible (C4D) and a resistant (Albany) strain of guinea pig

Despite similar levels of natural antibodies and treponemicidal activity, 83% of fourth complement component-deficient (C4D) mother guinea pigs developed ulcerative lesions to a challenge of 5 x 10(7) Treponema pallidum, whereas 75% of offspring 1 to 5 days old were temporarily (2-3 months) resistant to development of dermal lesions. In contrast, only 17% of Albany-strain mothers developed small papular lesions, while 68% of 1- to 5-day-old newborns developed large papular or ulcerative lesions within 9-15 days postinfection. These findings, together with the late development of both dermal lesions and antibodies in C4D neonates, preclude the concept of an antibody-associated natural resistance. T. pallidum infection in either C4D or Albany neonates was not associated with depletion of any particular cell population in lymphoid tissue. However, marked age- and strain-dependent histologic differences were noted. Histologic examination of lymph nodes and spleens from 17-day-old and 3- to 4-month-old animals showed that maturation of lymphoid tissues in C4D animals lagged behind the Albany strain at either age. Moreover, 75% of C4D newborns contained significantly higher levels of immunomodulatory alpha 1 fetoprotein than Albany neonates. The possibility that differences in susceptibility to T. pallidum infection between C4D and Albany guinea pigs as neonates and again as adults is the result of genetically associated changes in immunologic recognition is discussed.