Anaemia in systemic lupus erythematosus: from pathophysiology to clinical assessment

Laboratory tests in the diagnosis and follow-up of pediatric rheumatic diseases: an update

OBJECTIVES

We reviewed the literature to evaluate the role of common laboratory tests and to examine the recent progress in the laboratory diagnosis of pediatric rheumatic diseases.

METHODS

We used the PubMed database (1950-2008) to search for the keywords "laboratory," "erythrocyte sedimentation rate" (ESR), "C-reactive protein" (CRP), "blood cytology," "procalcitonin" (PCT), "complement system," "ferritin," "antistreptolysin O titer" (ASO), "autoantibodies," "genetic studies," in conjunction with "rheumatic disease in children" and "pediatric autoimmune diseases." All relevant original and review articles in English were reviewed as well as textbooks of pediatric rheumatology.

RESULTS

Laboratory tests (ESR, CRP, blood cytology, complement system, ferritin, ASO titer) play an important role in confirming a diagnosis and in the follow-up of rheumatic diseases in the pediatric age group. The ESR is probably the most widely measured index of the acute phase response. Measurement of CRP is very useful in the rapid diagnosis of infection as a progressive increase can be shown in the first 48 hours. Also, the subsequent fall in serum CRP concentration on resolution of inflammation is useful for monitoring the efficacy of treatment. In chronic diseases, a combination of CRP and ESR may provide the most useful information. Cytopenia and different forms of anemia can be encountered in many rheumatic diseases: they can be related to disease activity or to therapeutic side effects. Determination of complement levels (C3 and/or C4) is useful in the follow-up of systemic lupus erythematosus (SLE) and membranoproliferative glomerulonephritis. Ferritin is a laboratory hallmark of primary and secondary hemophagocytic lymphohistiocytosis. ASO titer should be obtained to confirm a diagnosis of acute rheumatic fever; other important antibody markers of streptococcal infection include antihyaluronidase, antideoxyribonuclease B, and antistreptokinase antibodies. We also found that, in the pediatric age, the main indication for synovial fluid analysis is suspected joint infection. Antinuclear antibodies, anti-Smith antigen, and anti-double-stranded DNA antibodies are important in the diagnosis of SLE, are useful prognostic markers, and facilitate clinical and treatment follow-up. Anti-SSA/Ro and anti-SSB/La antibodies are associated with Sjögren's syndrome and congenital heart block, while the anti-U1 small nuclear ribonucleoprotein antibodies show high specificity for mixed connective tissue disease. Repetitive spontaneous abortions, thrombocytopenia, and many types of venous or arterial thrombosis are associated with antiphospholipid antibodies. The presence of cytoplasmic antineutrophil antibodies is essential in the diagnosis of Wegener granulomatosis. The discovery of underlying single causative gene defects led to the identification of several autoinflammatory diseases, a group of genetic disorders characterized by recurrent attacks of inflammation (hereditary periodic fever syndromes). These include familial Mediterranean fever due to mutations in the Mediterranean fever (MEFV) gene, hyperimmunoglobulinemia D syndrome due to mutations in the MK gene for mevalonate kinase, cryopyrinopathies such as Muckle-Wells syndrome or neonatal-onset multisystemic inflammatory disease (neonatal-onset multisystemic inflammatory disease or chronic infantile neurological cutaneous and articular (CINCA)) associated with cold-induced autoinflammatory syndrome 1 gene mutations, and tumor necrosis factor receptor-associated periodic syndrome due to mutation of TNF receptor I gene.

CONCLUSIONS

Laboratory investigations play an important role in the diagnosis and follow-up of inflammatory rheumatic diseases in children. A good history and a complete physical examination are the best screening tests. Routine laboratory tests are useful to confirm a suspected diagnosis, to assess disease activity, and to measure the response and toxicity to treatment. Only a few tests represent diagnostic criteria such as antinuclear antibodies and anti-double-stranded DNA in SLE or cytoplasmic antineutrophil cytoplasmic autoantibodies in Wegener's granulomatosis. Recent advances in molecular genetics have impacted diagnosis, pathogenesis, and treatment in genetic fever syndromes.

Combined pure red cell aplasia and autoimmune hemolytic anemia in systemic lupus erythematosus with anti-erythropoietin autoantibodies

A 42-year-old woman with systemic lupus erythematosus was admitted to our hospital because of severe anemia. Her bone marrow was almost normocellular and erythroblasts were nearly absent. Laboratory data showed elevated levels of lactate dehydrogenase and positive findings on Coombs' tests. On the basis of these findings, her anemia was diagnosed as the overlap of pure red cell aplasia with autoimmune hemolytic anemia. Radioimmunoprecipitation assay revealed that her serum was positive for anti-erythropoietin antibodies before therapy. Furthermore, the autoantibodies inhibited proliferation of an erythropoietin-dependent cell line in a dose-dependent manner. Immunosuppressive treatment improved the anemia accompanied with disappearance of the autoantibodies.

Pharmacotherapy of lupus nephritis: time for a consensus?

BACKGROUND

The optimal therapy for lupus nephritis has been the subject of considerable debate.

OBJECTIVE

To provide evidence- and expert-based recommendations.

METHODS

To review the literature and the European League Against Rheumatism recommendations.

RESULTS

Risk stratification based on histological, demographical, clinical and laboratory characteristics allows the identification of patients at high risk for loss of renal function, and thus more likely to benefit from more aggressive therapy. Achieving remission within the first months of treatment, irrespective of the agent used, correlates with good long-term renal outcomes; maintenance of remission can be achieved with less toxic therapies. Aggressive management of atherosclerosis risk factors and renoprotective therapy for those patients with chronic renal disease improve long-term survival and prognosis.

Haemolytic anaemia in a multi-ethnic cohort of lupus patients: a clinical and serological perspective

Systemic lupus erythematosus is a chronic autoimmune disease that can be associated with a variety of haematological manifestations. We identified 76 patients with haemolytic anaemia in a cohort of 1251 unrelated female lupus patients enrolled in our studies. The presence of the various American College of Rheumatology clinical criteria for lupus and serological specificities were determined in lupus patients with haemolytic anaemia and compared with a group of race-matched control lupus patients without haemolytic anaemia. Clinical data were obtained from medical records, and serological specificities were determined in our clinical immunology laboratory at OMRF. The presence of haemolytic anaemia in lupus patients was associated with a higher frequency of proteinuria (OR = 2.70, P = 0.000031), urinary cellular casts (OR = 2.83, P = 0.000062), seizures (OR = 2.96, P = 0.00024), pericarditis (OR = 2.21, P = 0.0019), pleuritis (OR = 1.72, P = 0.028) and lymphopenia (OR = 1.79, P = 0.015). These findings were independent of the presence of thrombocytopenia, which was approximately five times more common in lupus patients with haemolytic anaemia. Lupus patients with haemolytic anaemia were about 8 years younger than lupus patients without haemolytic anaemia at the time of disease onset (P = 0.000001). In the absence of thrombocytopenia, lupus patients with haemolytic anaemia were approximately two times more likely to have anti-dsDNA antibodies (P = 0.024). The presence of haemolytic anaemia is associated with a subset of lupus characterized by a younger age of disease onset, and a more severe disease with a higher likelihood of renal involvement, seizures, serositis and other cytopenias.

Elderly-Onset Systemic Lupus Erythematosus

Systemic lupus erythematosus is an autoimmune multi-system disease of uncertain aetiology with highly variable clinical manifestations. Women of child-bearing age are most often affected; however, approximately 10-20% of cases occur in older patients. Elderly-onset lupus has been defined in various studies as onset of lupus after age 50-65 years. Menopause and changes in cellular immunity with aging may contribute to development of lupus in older adults. Many studies suggest that the clinical and serological features of elderly-onset lupus differ from those of lupus in younger patients. Arthritis, fever, serositis, sicca symptoms, Raynaud's syndrome, lung disease and neuropsychiatric symptoms are more common in patients with elderly-onset lupus, while malar rash, discoid lupus and glomerulonephritis are less common in elderly-onset patients compared with younger lupus patients. Most elderly-onset lupus patients have a positive anti-nuclear antibody test, but the prevalence of anti-double-stranded DNA and hypocomplementaemia is lower in elderly-onset patients than in younger patients. Rheumatoid factor, anti-Ro/Sjögren's syndrome (SS) A and anti-La/SSB are more often positive in elderly-onset patients. The diagnosis of elderly-onset lupus may be delayed for many months: insidious onset, low prevalence and similarity to other more common disorders make the diagnosis of lupus challenging in this population. Treatment of lupus in the elderly may be complicated by co-morbidities and increased risk of toxicities from usual treatments. Optimal management of elderly-onset lupus is empiric because of a lack of randomised controlled studies. However, the approach to treatment is similar regardless of the age of the patient. This article discusses the prevalence, clinical course, serological features, prognosis and treatment of elderly-onset systemic lupus erythematosus.

Prevalence of secondary hematologic disorders in the antiphospholipid syndrome: impact on coagulation risk

Hematologic abnormalities may occur in antiphospholipid antibody syndrome. The most common of these abnormalities is thrombocytopenia. The mechanism by which low platelet counts occur is not known but studies continue to elucidate the potential role of autoantibodies and cell surface markers. The risk for thrombosis in patients with thrombocytopenia does not appear to be related to the presence of thrombocytopenia itself. Innovative treatment with anti-CD20 antibodies may be of benefit in reversing thrombocytopenia and treatment with splenectomy does not appear to increase the risk for subsequent thrombosis. Hemolytic anemia is associated with antiphospholipid antibodies as well, but the risk for thrombosis in patients with hemolytic anemia is not clearly elevated. Diagnostic features of disseminated intravascular coagulation may co-occur with the antiphospholipid syndrome and may be associated with a catastrophic clinical presentation.