Kidney-limited thrombotic microangiopathy in patients with SLE treated with romiplostim.

We present the case of a 19 year-old Caucasian female with history of systemic lupus erythematosus (SLE) and normal baseline kidney function who developed severe acute renal failure following treatment of thrombocytopenia with the thrombopoietic agent romiplostim. Percutaneous kidney biopsy revealed thrombotic microangiopathy (TMA) without immune complex lupus glomerulonephritis. We discuss pathogenesis and differential diagnosis of TMA in patients with SLE and raise concerns regarding the use of thrombopoietic agents in such patients. Based on favorable long-term outcome in our case aggressive treatment and in particular prolonged use of plasma exchange in these patients are advocated.

Acute antibody-mediated rejection following heart transplantation.

Acute antibody-mediated rejection (AMR) in heart transplantation is often associated with hemodynamic compromise, and is associated with increased mortality and development of accelerated transplant coronary artery disease (TCAD). The diagnosis of AMR has historically been controversial and outcomes with aggressive immunosuppressive therapy including plasmapheresis and cyclophosphamide are poor. Advances in diagnostic techniques like the demonstration of immunopathologic evidence for antibody-mediated rejection by deposition of the complement split product C4d in tissue and detection of anti-HLA antibodies by flow cytometry will assist in further characterizing AMR. Immunosuppression targeting B-lymphocytes and use of m-TOR inhibitors to alter the predilection to develop TCAD and improve survival in AMR remains to be proven.

Prospective measure of serum 3-nitrotyrosine levels in systemic lupus erythematosus: correlation with disease activity.

Systemic lupus erythematosus (SLE) is a prototypical autoimmune disease. Overproduction of nitric oxide (NO) has been implicated in its pathogenesis. Several retrospective studies have indicated a correlation between serum nitrate and nitrite (NOx) and disease activity. This measure of NO production can be falsely elevated by exogenous dietary and medication sources of NOx and variably reduced by serum thiols. These variables can make NOx a less reliable tool for studying the role of NO in SLE. Peroxynitrite, a by-product of NO and superoxide, nitrates tyrosine moieties. The resulting 3-nitrotyrosine (3NT) serves as a long-term indicator of NO-mediated protein modifications that is not affected by exogenous sources of NOx or serum thiols. We hypothesized that for these reasons serum 3NT levels would correlate with lupus disease activity more significantly than serum NOx. To address this hypothesis, we prospectively evaluated lupus disease activity, serum protein 3NT levels, and NOx levels in a cohort of lupus patients at 3-month intervals. Serum 3NT correlated with disease activity among African-Americans, while NOx correlated with disease activity among Caucasians. Subjects with active lupus nephritis had higher levels of serum 3NT than those without renal disease. Immunohistochemical analysis of renal biopsies from subjects with active proliferative lupus nephritis revealed renal expression of inducible NO synthase. The results of this study suggest that overproduction of NO may play a pathogenic role in SLE and lupus nephritis. Serum 3NT may be a useful, new tool for studying the contributions of NO to the pathogenesis of SLE.

Resistance to remnant nephropathy in the Wistar-Furth rat.

The Wistar-Furth rat, an inbred strain resistant to actions of mineralocorticoids, was used to study the concept that mineralocorticoids contribute to progressive renal injury. It was postulated that if chronic nephropathy depends on aldosterone and if Wistar-Furth rats are resistant to aldosterone, remnant nephropathy would be attenuated in Wistar-Furth rats. Wistar-Furth rats and control Wistar rats were subjected to 5/6 nephrectomy or a sham procedure and then followed for 4 wk. Renal ablation resulted in hypertension at 4 wk in both strains (164+/-5 [Wistar-Furth] versus 184+/-7 [Wistar] mm Hg mean arterial pressure), with sham animals remaining normotensive (134+/-6 mm Hg). Renal damage in response to 5/6 nephrectomy was greatly decreased in Wistar-Furth rats compared with Wistar rats. Albuminuria was markedly less in Wistar-Furth rats (12.7+/-4.2 [Wistar-Furth] versus 97.4+/-22.6 [Wistar] mg/d per 100 g body wt, P<0.01). Glomerular damage, consisting of mesangial proliferation, mesangial lysis, and segmental necrosis, was observed in 42% of glomeruli from Wistar rats but in 0% of glomeruli from Wistar-Furth rats (P<0.01). To address the possibility that higher BP in partially nephrectomized Wistar rats mediated the greater renal damage, the study was repeated, with Wistar rats (not Wistar-Furth rats) being treated with a hydralazine-reserpine-hydrochlorothiazide regimen. Although this antihypertensive regimen equalized BP (conscious systolic) (144+/-8 mm Hg [Wistar] versus 157+/-7 mm Hg [Wistar-Furth] at 4 wk), albuminuria remained more than 10-fold greater in Wistar rats. In summary, renal damage upon 5/6 nephrectomy was markedly reduced in Wistar-Furth rats, a finding not attributable to reduced systemic BP. Since Wistar-Furth rats have been shown previously to be resistant to the actions of mineralocorticoids, the data from the present study support the hypothesis that aldosterone mediates, at least in part, the renal injury attendant to renal mass reduction.

Cyclosporine-induced hemolytic uremic syndrome and hemorrhagic colitis following renal transplantation.

Nephrotoxicity remains one of the most common side-effects of cyclosporine in the setting of transplantation. Acute reversible decreases in glomerular filtration rate and chronic irreversible renal damage are the most common manifestations, but hemolytic uremic syndrome and thrombotic thrombocytopenic purpura have been reported. Prognosis of cyclosporine-associated de novo hemolytic uremic syndrome (CyA-HUS) is poor, with nearly half of affected patients losing function in the transplanted kidney. Therapeutic options are limited, but good outcomes have been reported by switching patients from cyclosporine to tacrolimus. We report an unusual presentation of CyA-HUS associated with hemorrhagic colitis following renal transplantation. The patient was successfully managed by switching from cyclosporine to tacrolimus.

The interaction of maintenance interferon with cytolytic cells in patients with multiple myeloma who responded to cytotoxic chemotherapy.

STUDY OBJECTIVE: To determine the long-term effects of maintenance interferon on CD56+ and CD3+ cell activity. DESIGN: Prospective phase II trial. SETTING: Tertiary medical center and level 2 Veterans Administration hospital. PATIENTS: Seven patients (age 45-74 yrs) with multiple myeloma who had reached the plateau phase from cytotoxic chemotherapy, and seven age- and sex-matched controls. INTERVENTIONS: All patients were given interferon-alpha 2b 3 x 10(6) U/m2 3 times/week. MEASUREMENTS AND MAIN RESULTS: The CD56+, CD3+, and CD16+ counts were determined by flow cytometry in both peripheral blood and bone marrow. Natural killer (NK) cell functional activity was determined by a 51chromium release assay. Monocyte cell numbers were determined from the white blood cell count with differential. Interleukin-6 (IL-6) concentrations were determined by a commercially available enzyme-linked immunosorbent assay. During the 24-week study, the peripheral blood CD3+ and monocyte counts in patients with myeloma remained constant (p > or = 0.39) but their absolute CD56+ counts decreased significantly (p = 0.05). In peripheral blood, CD56+, CD16-, CD3- was the predominant phenotype in patients. The predominant phenotype in bone marrow was CD56+, CD16-, CD3+ at baseline but changed to CD56+, CD16-, CD3- by week 24. The cytolytic activity of NK cells significantly increased in bone marrow (p = 0.05) whereas it remained stable in the peripheral blood (p = 0.55), but only half that of the controls. Concentrations of IL-6 did not increase significantly during the study. CONCLUSION: In peripheral blood, NK cell activity remained stable in patients but was significantly lower than that in controls, probably secondary to the predominance of the CD56+, CD16-, CD3- phenotype in the patients. In contrast, NK cell activity increased significantly in bone marrow despite the predominance of the CD56+, CD16-, CD3- phenotype by week 24.

The effect of lymphocytes from renal transplant patients on glomerular basement membrane sulfate uptake.

We have studied the effect of peripheral blood mononuclear cells (PBMC) from renal transplant patients on 35sulfate uptake by rat glomerular basement membrane (GBM). Nine patients were included in the study; six were studied during an episode of acute allograft rejection and seven while not undergoing acute rejection. The sulfate uptake index, calculated as the ratio between uptake by GBM from rat glomeruli cocultured with PBMC and 35sulfate incorporation by GBM from glomeruli cultured alone, was significantly higher when glomeruli were cocultured with PBMC from patients undergoing an acute rejection (3.26 +/- 1.18, mean +/- SEM) than it when glomeruli were cocultured with PBMC from nonrejecting transplant patients not showing proteinuria (0.81 +/- 0.11) (P = 0.0053). After reversing the acute allograft rejection with resolution of proteinuria, the sulfate uptake index returned to normal in four of five patients. The fifth patient had persistent nephrotic syndrome and his sulfate uptake index remained elevated. These findings are similar to those observed in idiopathic minimal lesion nephrotic syndrome patients in relapse. Because the GBM sulfated compounds may play a role in glomerular permeability to plasma proteins, by acting on these compounds PBMC may be a common mechanism for proteinuria.

Immunophenotypic analysis of non-Hodgkin's lymphomas.

Flow cytometric cell analysis with fluorescence-labeled antibodies has become a very useful methodology for the immune phenotyping of lymphocytes. The continued evaluation of lymphocyte cell surface antigens has been of value in this respect by providing a clear picture of lymphocyte differentiation steps. Thus it is now possible to precisely identify lymphocytes of abnormal phenotype which may represent malignant cells. Detection of monotypic populations of lymphocytes represents a monoclonal expansion of a lymphocyte subset which is the hallmark of malignancy. In the case of B cell lymphoma, detection of monotypic populations rests on the finding of a monoclonal expansion of a cell type bearing one type of light chain and of heavy chain and/or one of the specific B lymphocyte differentiation antigens. The diagnosis of T cell malignancy is more difficult to establish and a diagnosis of T cell lymphoma rests on the finding of an abnormal phenotype. Thus flow cytometry in combination with histomorphologic examination is a useful technique for the more precise diagnosis of lymphomas and for the establishment of treatment protocols.

Significance of common acute lymphoblastic leukemia antigen (cALLA) positive cells in bone marrow of children off therapy in complete remission.

Bone marrows from 21 children with acute lymphoblastic leukemia in complete remission (CR) and off therapy for 14 months to 10 years were examined by flow cytometry with a panel of monoclonal antibodies. Significant percentages of cALLA+ cells of low fluorescence intensity were present up to 9 years after CR. These results emphasize the need to interpret flow cytometry results in light of the findings that low intensity cALLA+ cells represent a normal population of immature, non-malignant lymphoid cells.

Are lymphocyte subset determinations affected by storage conditions?

The effect of overnight storage, either at room temperature or at 4 degrees C, on total T cells, helper cells, suppressor cells, and HLA-DR-positive cells was determined by flow cytometry and fluoresceinated monoclonal antibodies on peripheral whole blood samples. No differences were noted in any of the subsets regardless of storage conditions when samples were analyzed within 24 hr.