Updating on the pathogenesis of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a multi-organ autoimmune disease whose pathogenesis is multifactorial lying on genetic, environmental factors and on abnormalities of both the innate and the adaptive immune system. The induction, maintenance and progression of the disease are a multi-step process that may take long time eventually leading to tissue injury. Several genes have been associated to SLE susceptibility; each of them displaying a small effect suggesting the need of an association. However, the gene-gene and gene-environment interactions are still matter of research. Environmental factors, both external such as physical and infectious agents and internal such as gender and hormonal profile, may influence the disease manifestation. SLE is characterized by a complex array of immune abnormalities affecting both the innate and the adaptive immunity. All these processes play a role in the defective clearance of chromatin material that is overexposed to the afferent limb of the immune system leading to an autoimmune response facilitated by defective regulatory mechanisms. The production of a wide panel of autoantibodies represents the ultimate events responsible for tissue aggression. Finally, tissue damage is influenced by the presence of local factors responsible for the final aggressivity of the lesions and of the clinical manifestations.

Immune function in children born to mothers with autoimmune diseases and exposed in utero to immunosuppressants.

The administration of immunosuppressive drugs during pregnancy is often necessary in women with autoimmune diseases. Teratogenicity of immunosuppressives during pregnancy has been evaluated, only few data exist about the effects on immune systems. We therefore performed a pilot study on the influence of foetal exposure to immunosuppressives on immune function of babies born to mothers with autoimmune disorders. We investigated serological and cellular parameters as indicators of immune system status. We included in the study 14 babies (mean age 11 months, range 1-24) born to mothers with autoimmune diseases and exposed in utero to different immunosuppressants and, as controls, 14 babies whose mothers had autoimmune manifestations but did not receive immunosuppressive therapy. We evaluated: (i) complete blood count, (ii) immunoglobulin levels and IgG subclasses, (iii) antibody response to hepatitis B vaccine, (iv) leukocyte subpopulations and (v) interleukin-2 and interferon gamma in vitro production by resting or activated peripheral blood mononuclear cells. We did not find statistically significant differences between exposed and not exposed babies or among treatments for the tested parameters. Immunosuppressive regimens currently in use for controlling maternal autoimmune disorders do not significantly affect the immune status of the offspring.

Response to tetanus vaccination in infants exposed in utero to immunosuppressants for maternal autoimmune disorders.

Immunosuppressive drugs given during pregnancy to mothers suffering from a systemic autoimmune disease (AID) can cross the placenta, thus being potentially able to affect the offspring immune system. Aim of our study was to evaluate the in vivo immune function of a series of these newborns. Twenty-two babies born from mothers suffering from autoimmune diseases (AID) who had been taking immunosuppressive drugs during pregnancy were evaluated for their response to vaccination with C. Tetani toxoid. Six babies born from mothers receiving low-dose aspirin only were used as controls. The immune response to C. Tetani vaccination was evaluated with an ELISA to detect circulating antibodies. Five children out of 28 (17%) did not achieve a protective titer of anti C. Tetani toxoid IgG. No clear relationship was found between specific drug exposure and antibody response. Our findings suggest that maternal immunosuppressive treatment given for a systemic AID can affect the response to an active immunization, without specificities for drug types used.

[Arthritis and infections]. / Artriti e infezioni.

Arthritis caused by infectious agents can be secondary to direct invasion of the joint space or to immune mechanisms (subsequent to or concomitant to an infection). Septic arthritis refers to a situation when bacteria can be cultured in synovial fluid. Arthritis can complicate for example meningococcemia or infection by Neisseria gonorrhoeae or Haemophilus influenzae. Reactive (postinfectious) arthritides are an important diagnostic category within a pediatric rheumatology practice. Yersinia and, less frequently, Salmonella, play an important role in postdiarrheal disorders. The arthritis that can ensue is usually oligoarticular and occurs 1-2 weeks after the enteric infection. Reiter's syndrome, rare in the pediatric age, is characterized by the triad urethritis-conjunctivitis-arthritis. Postviral arthritides can occur after a variety of viral infections, including Parvovirus B19, rubella, and others (e.g. hepatitis B, Epstein-Barr virus, chickenpox, mumps). Especially in patients with acute arthritis, the presence of preceding infections should always be investigated. Although the majority of postinfectious arthritides are self-limiting in nature and do not require specific treatment, conditions such as Lyme borreliosis and rheumatic fever can be associated with significant morbidity, and sometimes can be even lethal.

Alterations in the immune system of children from mothers treated with immunosuppressive agents during pregnancy.

Many of the immunosuppressive drugs that are used during pregnancy can cross the placental barrier and enter the foetal circulation, with a possible impact on the foetal immune system. We have evaluated the immune function of children born from mothers treated with immunosuppressants for connective tissue diseases. A total of nine babies, whose six mothers had been taking cyclosporine A (two), azathioprine (one) and dexamethasone (three) during pregnancy, together with 14 babies from mothers with similar diseases but who had not been treated (controls) were investigated. Complete blood count, IgA, IgG, IgM, IgG subclasses, and lymphocyte subpopulations were determined in all cases. Moreover, serum levels of anti-HBsAg and presence of autoantibodies (ANA, ENA) were also evaluated. Patients were tested at a mean age of 11 months (range, 1-17). Only a minor proportion of our patients displayed low values for age (mainly, IgA and IgG2), but none of the parameters tested resulted significantly different in patients than in controls. All children responded satisfactorily to hepatitis B vaccination. Although our results are preliminary, we conclude that prenatal exposure to immunosuppressive drugs does not have a profound effect to the developing immune system. More data and a longer follow-up are needed to confirm these results.

Ultraviolet light exposure is not a requirement for the development of cutaneous neonatal lupus.

Cutaneous neonatal lupus erythematosus (NLE) is a rare disorder, linked to the presence of transplacentally acquired maternal autoantibodies (anti-ENA). NLE skin lesions frequently appear in the second or third month of life, and ultraviolet exposure is thought to be an initiating factor since it can externalize intranuclear autoantigens at the cell surface. We report a baby who was born already with an extensive NLE rash, suggesting that sun exposure is not a requirement for the development of NLE skin lesions. A 31-year-old woman affected with mixed connective tissue disease gave birth to a female after 38 weeks of gestation. Pregnancy was uneventful and no perinatal complications were seen. The mother was positive for anti-RNP, but negative for anti-SSA/Ro and SSB/La autoantibodies. Already at birth, an extensive scarring rash with a few erythematosus lesions was present on the baby's face and scalp; this progressed over the following months, and subsequently stabilized. Anti-RNP were present in the baby's serum. Due to the unusual features of the disease expression, a skin biopsy was performed at age 5 months; results were consistent with the diagnosis of NLE, showing mononuclear cell infiltration and immunoglobulin deposition. No other features of NLE were detected. This observation is unusual for: (1) the presence of an NLE rash in the absence of anti-SSA/Ro; (2) the scarring and atrophic characteristics of the lesions; and (3) the development already in utero. This latter finding argues against sun exposure being necessary for lesion induction.

Osteoporosis.

Bone mass is determined primarily by genetic influences, but exogenous factors may also play a major role. The prevention of osteoporosis can start at childhood. Optimal achievement of peak bone mass during childhood and adolescence is important to minimize future fracture risk. Chronic inflammatory diseases can have a detrimental effect on bone mass through a variety of mechanisms. Different diagnostic methods for detecting osteoporosis (eg, dual x-ray absorptiometry, quantitative computed tomography, ultrasounds) are in use or under investigation. New treatment options are available; among these, the use of bisphosphonates seems to be the more promising approach.