PubMed Health⌕ Search

Biomedical subjects

K Erlendsson

Publications and source records attributed to K Erlendsson.

16 recordsLinked to original sources
PubMed2004

A discrepancy between liquid phase and gel phase assays for evaluation of total complement activity and some possible explanations.

This study was conducted to investigate the frequency and origin of discrepant assay results between two haemolytic assays which both measure activity of the classical pathway of complement (CH50) by haemolysis of sheep red blood cells (SRBCs). One is conducted in gel phase using undiluted sera and the other in liquid phase with sera in 1/100 dilution. The majority of discrepant readings are observed as low or absent haemolysis in the gel phase, with values within or above the normal range in the liquid phase. The incidence of discrepant assay readings was evaluated in 300 samples. Furthermore, 28 samples showing the most discrepant readings were investigated further for disturbing factors. Factors evaluated in the test sera were mannose-binding lectin, C-reactive protein (CRP), immune complexes, antibodies to SRBCs, rheumatoid factor and immunoglobulin A (IgA) and IgG anti-C1q antibodies. The results showed that discrepant readings are present in 10% of the 300 samples and false low gel assay readings account for 6.3%. The majority (68%) of the discrepant samples contained a heat-stable-inhibiting factor, and the main mediators found were elevated levels of IgA anti-C1q antibodies and antibodies to SRBCs. This could indicate a clinically relevant factor in the test sera but can also result from the difference in assay design.

Antigen-Antibody Complex↗
PubMed2002

Increased T-lymphocyte apoptosis/necrosis and IL-10 producing cells in patients and their spouses in Icelandic systemic lupus erythematosus multicase families.

The objective of this study was to evaluate apoptosis and production of IL-10 in SLE patients, their spouses and first-degree relatives in Icelandic SLE multicase families. Previously, increased IL-10 production has been found in all three groups. As IL-10 has been found to induce apoptosis in SLE, the percentage of lymphocytes undergoing apoptosis was evaluated, as well as the possible correlation between apoptosis and IL-10 production. Apoptosis and IL-10 production were studied in SLE patients (n = 12) from SLE multicase families and their spouses (n = 12) and a matched control group of healthy individuals (n = 10). The proportion of T and B lymphocytes undergoing apoptosis at 0, 24, 48 and 72 h was detected by flow cytometry using Annexin V and PI staining and the rate of apoptosis was calculated. IL-10 production was studied simultaneously by ELISpot analysis of freshly isolated peripheral blood mononuclear cells. In addition, T lymphocyte apoptosis at t = 0 was investigated in a group of non-household first-degree relatives (n = 10) and controls (n = 10). Antinuclear and antilymphocyte antibodies were analysed in all the groups. The SLE patients as a group had a significantly increased percentage of T lymphocytes in apoptosis at 0 and 48 h and a significantly higher number of IL-10 producing cells as compared with the healthy controls (P = 0.03, 0.02 and 0.03, respectively). The spouses also had significantly increased percentage of T lymphocytes in apoptosis (t = 0) and a significantly higher number of IL-10-producing cells when compared with healthy controls (P = 0.01 and 0.02, respectively). There were no significant differences between the patients and their spouses. For apoptosis of B lymphocytes no difference was found between the groups. The SLE patients as a group had the highest rate of apoptosis. No correlation between the degree and rate of apoptosis and the number of IL-10-producing cells was detected. The first-degree relatives did not have increased percentage of T lymphocytes undergoing apoptosis at t = 0 compared with healthy controls. The SLE patients had higher titres of ANA compared with the other groups. No correlation was detected between the ANA titre and the percentage of lymphocytes undergoing apoptosis. There was no correlation between disease activity as measured by SLEDAI and apoptosis. In conclusion, our results suggest that environmental factors common to both SLE patients and their spouses are associated both with the increased apoptosis and increased spontaneous production of IL-10, thus providing support for the notion that both environmental and genetic factors influencing apoptosis are of importance for the development of SLE.

Antibodies, Antinuclear↗
PubMed2001

The inheritance of rheumatoid arthritis in Iceland.

OBJECTIVE: Rheumatoid arthritis (RA) is the most common form of inflammatory arthritis. Although there is a large body of evidence suggesting that RA is immune mediated, the etiology remains unresolved. Twin studies have shown disease concordance rates of approximately 15% in monozygotic twins and 4% in dizygotic twins, while the estimated risk ratio for siblings of RA patients ranges from 5 to 8. Our goal was to use genealogic data from Iceland to further investigate the genetic component of RA. METHODS: Data were obtained from a population-based, computerized genealogy database that was developed to examine multigenerational relationships among individuals in the relatively homogeneous population of Iceland. Using an algorithm, the minimum founder test, we calculated the least number of founders required to account for a list of RA patients, and compared it with 1,000 sets of same-sized matched control groups. In addition, we estimated the kinship coefficient and risk ratios for relatives of the RA patients. RESULTS: Several familial clustering tests demonstrated that the RA patients were more related to each other than were the average control set of Icelanders. A significantly fewer number of founders was necessary to account for our patient list than for the random sets of matched controls (P < 0.001), and the average pairwise identity-by-descent sharing was greater among the patients than among the control sets (P < 0.001). In addition, there was an increased risk of RA in first- and second-degree relatives of the patients; e.g., for siblings, the risk ratio was 4.38 (95% confidence interval 3.26-5.67), and for uncles/aunts, the risk ratio was 1.95 (95% confidence interval 1.52-2.43). CONCLUSION: The familial component of RA is shown to extend beyond the nuclear family, thus providing stronger evidence for a significant genetic component to RA.

Algorithms↗
PubMed1998

An enzyme based assay for the measurement of complement mediated binding of immune complexes to red blood cells.

A new in vitro method is presented for measuring directly the ability of sera to induce binding of immune complexes (ICs) to erythrocytes (ICRB assay). The assay measures the binding of alkaline phosphatase (AP)-anti-alkaline phosphatase (anti-AP) complexes formed in the presence of the test sera to the complement receptor 1 (CR1) on normal human red blood cells (RBCs). By using a standard serum source, the assay can also be used to measure the IC binding ability of RBCs from different donors. As compared to the traditional CH50 method, the ICRB assay generally showed more pronounced abnormality in 10 individuals tested, of whom 5 had primary deficiency of classical pathway components. Seven out of ten individuals had systemic lupus erythematosus (SLE) and 2/10 had other rheumatic diseases without primary complement deficiency. The ICRB measured in samples from 9 other patients with SLE was significantly decreased when compared to values from 80 normal individuals. ICRB in serum samples from a C2 deficient SLE patient collected during plasma infusion treatment reflected closely the rising amount of C2 in the serum. Using RBCs from different donors ICRB activity correlated well with the numbers of CR1 as measured by a flow cytometric assay (FCA). These methods should be valuable for measuring the overall IC clearance capacity of the blood and have the advantage that the use of radioactive isotopes is avoided.

Animals↗
PubMed1998

Participation of factor B in residual immune complex red cell binding activity observed in serum from a C2-deficient systemic lupus erythematosus patient may delay the appearance of clinical symptoms.

OBJECTIVE: To investigate whether participation of factor B (FB) in immune complex transport might explain long periods of clinical remissions in a homozygous C2-deficient patient with systemic lupus erythematosus (SLE) treated regularly with plasma infusions. METHODS: Immune complex red cell binding (ICRB) was assayed as enzyme activity, C3d by enzyme-linked immunosorbent assay, and FB by immunoelectrophoresis. RESULTS: C2-deficient sera showed low-grade ICRB, which correlated with levels of FB. This activity could be blocked with antibodies to C1q, C4, or FB, but not by antibodies to C2. C3d levels in the patient's plasma changed during infusion, followed by a gradient increase during remission. Comparison of ICRB, C3d, and FB suggested an inverse relationship between FB levels and clinical symptoms. CONCLUSION: In C2 deficiency, FB may interact with C4 to provide a low-grade ICRB. This activity could be clinically significant in patients with C2 deficiency and explain why they are less prone to SLE than patients with C1q or C4 deficiency.

Antibodies↗
PubMed1998

C4AQ0 superimposed on a primary defect increases the susceptibility to systemic lupus erythematosus (SLE) in a family with association between C4AQ0 and SLE.

OBJECTIVE: To investigate the association of C4AQ0 with increased incidence of systemic lupus erythematosus (SLE) or positive serology (28%) in an extended Icelandic family, and whether this can be explained by impaired complement function in handling immune complexes (IC). METHODS: The ability of the classical pathway to opsonize nascent IC [alkaline phosphatase (AP)-anti-AP] and bind them to human erythrocytes was evaluated by the new ICRB assay. The capacity of erythrocytes from family members to bind nascent IC was also measured by a modification of the ICRB assay. IC levels were measured by complement consumption assay, C3d by a sandwich ELISA, factor B by immunoelectrophoresis, and the alternative pathway function by a hemolytic assay. RESULTS: Family members with homozygous or heterozygous C4AQ0 (47%) showed no impaired complement dependent opsonization of IC and binding to erythrocytes. Their factor B and alternative pathway function was normal. Fifty-six percent of the family members (n=18) had abnormally high IC levels, seemingly independent of C4AQ0. However, 6 of the 7 individuals with high IC levels and SLE symptoms had C4AQ0 compared to 2 of 11 symptom-free individuals with high IC levels. CONCLUSION: Our results suggest that the susceptibility for SLE in this family may result from 2 different defects, one leading to elevated IC levels, and another associated with C4AQ0 without detectable impairment in the complement dependent IC transport mechanism. Individuals with both abnormalities have increased susceptibility to SLE.

Antigen-Antibody Complex↗
PubMed1995

A study of the major histocompatibility complex in a Caucasian family with multiple cases of systemic lupus erythematosus: association with the C4AQ0 phenotype.

OBJECTIVE: In an epidemiological survey of systemic lupus erythematosus (SLE) in Iceland several families with multiple cases were identified. In one family, 35 individuals (family members and spouses) in 3 generations were studied clinically, tested for autoantibody formation, and typed for HLA and toxicity complement phenotypes. METHODS: Typing for HLA-A, B, C, DR, and DQ was performed by microlymphocytotoxic assay. In selected samples HLA-DR typing by polymerase chain reaction amplification with sequence specific primers was performed. C4 allotypes were defined by agarose gel protein electrophoresis followed by immunofixation with goat antisera. RESULTS: Five family members fulfilled 4 or more criteria for SLE. Additionally, 5 family members had clinical manifestations or positive serology but did not fulfill 4 ARA criteria. The mean age at onset of symptoms was 22 yrs (8-40). Other autoimmune diseases were not documented in family members. C4A null seemed to be highly associated with disease in this family. All except one patient with SLE and all those with clinical manifestations and positive serology had C4A null in the homozygous or heterozygous form. The individual with SLE and not carrying C4A null had both HLA haplotypes identical. It is noteworthy that there were 5 different C4A null bearing haplotypes involved, of which 3 originated from the spouses. CONCLUSION: Our results are consistent with the argument that C4A deficiency plays a role in the pathogenesis of SLE. There is, however, the possibility of an unidentified environmental or another genetic factor being involved.

Adolescent↗
PubMed1994

[Diffuse connective tissue diseases (DCTD)--a review].

The diffuse connective tissue diseases constitute a group of inflammatory diseases with the potential of involvement of many organ systems. The etiopathogenesis is thought to be multifactorial, involving the interaction between particular genetic background and exogenous agents. Recently theories regarding inherited defects in the clearing of immune complexes have been put forward. Serological markers are important diagnostic tools in many of these diseases and emphasize the role of autoimmunity. Epidemiological studies have demonstrated an increase in incidence in some of these diseases and because of selection bias many epidemiological studies may overestimate the severity of these diseases. Therapy aims at modulating and suppressing inflammation. A step towards more directed immune modulation is the use of cyclosporin A and monoclonal antibodies against various surface antigens and mediators in inflammation.

Antigen-Antibody Complex↗
PubMed1993

Splenic uptake of immune complexes in man is complement-dependent.

We have examined the effects of hereditary homozygous C2 deficiency on the processing of radiolabeled soluble immune complexes (IC). A patient with C2 deficiency was studied before and after treatment with fresh frozen plasma (FFP). Hepatitis B surface Ag (HBsAg):anti-HBsAg immune complexes were prepared in vitro using Ag radiolabeled with 123I, and injected intravenously. Dynamic and static gamma-scintigraphy was performed to delineate the sites and kinetics of complex clearance. The patient was initially studied when her C2 level and CH50 were zero, and again 1 wk later after treatment with 12 units of FFP, which normalized these parameters. Before treatment there was rapid uptake of complexes by the liver (t90% [time for 90% uptake] = 13.6 min) and rapid clearance from the circulation (t1/2 = 6.8 min). No splenic uptake was detected, and there was no binding of complexes to erythrocyte CR1. Between 30 and 60 min there was release of 11% of the tracer from the liver. In the second study, performed after normalization of classical pathway complement activity, the t1/2 of IC clearance increased to 9.8 min, and t90% was 27 min. Twenty percent of injected complexes now localized to the spleen, and there was no longer any release of complexes between 30 and 60 min. The kinetics of IC processing and the sites of uptake in this posttherapy study were closely similar to two normal subjects studied in parallel, with a maximum of 72% of injected complexes binding to erythrocytes. These observations indicate that the uptake of immune complexes in the spleen in humans is complement-dependent, and suggest that the observed predisposition to SLE in patients with complement deficiency may be related to abnormal processing of immune complexes.

Antigen-Antibody Complex↗
PubMed1993

Reciprocal changes in complement activity and immune-complex levels during plasma infusion in a C2-deficient SLE patient.

Although systemic lupus erythematosus (SLE) is abnormally common in individuals with complement deficiency, conclusive evidence has been lacking for a direct causal relationship between disease manifestations and a missing complement component. A patient with C2 deficiency and SLE has been treated with 56 courses of fresh frozen plasma (FFP) infusions over a period of 8 years. Each infusion, involving a total of 12 units of FFP administered in equal doses over 4 consecutive days, has consistently resulted in a transient restoration of the classical pathway of complement, and a full clinical remission lasting 6-8 weeks. This report is concerned with changes in the levels of immune complexes, C2 and C3d during an infusion cycle. Four progressively rising peaks in C2 and C3d were observed during the 4 days of the plasma infusion, and these peaks coincided with four reciprocally descending troughs in the levels of immune complexes. Identical fluctuations have been consistent in all the plasma-infusion cycles that have so far been monitored, and their consistent association with clinical remissions indicates a causal relationship between the C2 restoration and clinical remissions in this C2-deficient SLE patient.

Antigen-Antibody Complex↗
PubMed1993

Relation of antiphospholipid antibody and placental bed inflammatory vascular changes to the outcome of pregnancy in successive pregnancies of 2 women with systemic lupus erythematosus.

Histological changes in biopsies from the placental and placental bed in 2 successive pregnancies of 2 women with systemic lupus erythematosus and antiphospholipid antibodies were studied. In one of the first 2 pregnancies vasculitis was found in the spiral arteries of the placental bed biopsy, while the other showed perivascular inflammatory infiltration and deciduitis. This was associated with poor pregnancy outcome and elevated antiphospholipid antibodies (aPL). In the subsequent 2 pregnancies prednisolone treatment was tailored to suppress the aPL titer with markedly decreased inflammatory changes and no evidence of vasculitis in the spiral arteries of the placental bed was found. This was associated with a normal pregnancy outcome. A causal relationship between aPL and inflammatory vascular changes in the placental bed as well as a beneficial effect of the corticosteroid treatment in those two women in suggested.

Adult↗
PubMed1992

Disease manifestations in patients with isolated elevation of IgA rheumatoid factor.

In this retrospective study a comparison was made between the disease manifestations in patients with isolated elevation of IgA rheumatoid factor (RF) and patients with elevation of IgM RF. Of the 28 patients with isolated elevation of IgA RF, 14 (50%) had rheumatoid arthritis (RA) and 9 (32%) miscellaneous other inflammatory rheumatic disorders. It was found that 61% of these 23 rheumatic patients had disease manifestations from mucous membranes or secretory organs compared to 18% in the IgM RF positive group (p = 0.020). Patients with RA and an isolated elevation of IgA RF had more often mucosal or secretory symptoms than RA patients with elevation of IgM RF. We suggest that IgA RF may be a marker for activation of the mucosal or secretory immune system. The relationship between IgA RF and non-articular symptoms is discussed.

Arthritis, Rheumatoid↗
PubMed1990

Increased amounts of C4-containing immune complexes and inefficient activation of C3 and the terminal complement pathway in a patient with homozygous C2 deficiency and systemic lupus erythematosus.

Plasma and serum samples from a patient with homozygous C2 deficiency and severe systemic lupus erythematosus who responded with full clinical remission after plasma infusions were examined for immune complexes (IC), C3 activation products, and the terminal complement complex (TCC). Plasma contained large amounts of C4-containing IC but no C3-containing IC or complement activation products. Classical pathway activation in vitro did not lead to C3 activation or TCC formation as seen in normal serum, but a very efficient binding of C1q and C4 was found. No disturbances in alternative pathway activation were observed. The results indicate an impaired formation of C3-containing IC and an inefficient clearance of C4-containing IC, supporting the idea of a causal relationship between the dysfunctional classical pathway, pathophysiology, and clinical manifestations in this patient.

Antigen-Antibody Complex↗
PubMed1989

Successful plasma infusion treatment of a patient with C2 deficiency and systemic lupus erythematosus: clinical experience over forty-five months.

We describe a patient with C2 deficiency and severe systemic lupus erythematosus (SLE) that did not respond to conventional therapy. Over a period of 45 months, she was given 22 cycles of plasma therapy. For 6-8 weeks after each plasma infusion, there was a full clinical remission of the SLE, and a brief restoration of hemolytic complement activity. However, there were more prolonged increases in the activities of the complement components that are believed to be more directly involved in the clearance of immune complexes. Because of the theoretical risk that the infused complement might enhance inflammatory tissue damage, there has been some reluctance to try plasma replacement therapy in SLE patients with complement deficiency. We have not observed any adverse effects with the long-term use of this treatment, and our experience indicates that this therapeutic approach can be beneficial.

Adult↗
PubMed1988

Intraventricular gamma-globulin for the management of enterovirus encephalitis.

Although bacterial infections predominate in patients with hypogammaglobulinemia, patients who do not produce normal amounts of immunoglobulin also have an increased incidence of viral infections. This is particularly true of infections with enteroviruses. Echovirus encephalitis has been a major problem for patients with hypogammaglobulinemia. Neurologic damage, frequently resulting in death, has been common in such patients. Because there is an obligatory extracellular phase in the cell to cell spread of enteroviruses, therapy with immunoglobulin has been attempted. In certain patients intravenous and intrathecal gammaglobulin has temporarily halted progression of the disease, but no patients have been cured by this approach. In this report we detail treatment of three children with X-linked hypogammaglobulinemia who had encephalitis caused by echovirus infections. Despite doses of intravenous immunoglobulin that maintained the patients' IgG levels within the normal range, their condition deteriorated in all cases. Treatment with intraventricular immunoglobulin was then tried. In all three cases cerebrospinal fluid protein levels and cell counts returned to normal after this treatment and the echoviruses can no longer be isolated from the cerebrospinal fluid. Follow-up time has ranged from 18 months to 4 years. Ommaya reservoirs were placed into the lateral ventricle of each patient and concentrated (6%) immunoglobulin (Sandoglobulin) was injected into the reservoir on a daily basis. On Days 1 through 7 of the regimen patients were given 120, 300, 450, 510, 540 and 600 mg of IgG, respectively. Patients then received 300 mg daily for periods ranging from 1 week to 1 month. Cultures of cerebrospinal fluid removed from the reservoir were repeatedly analyzed to determine the need for further treatment. Clinically the patients improved markedly.(ABSTRACT TRUNCATED AT 250 WORDS)

Agammaglobulinemia↗