Immunogenicity of subcutaneous TNF inhibitors and its clinical significance in real-life setting in patients with spondyloarthritis.

KEY MESSAGES: Considerable proportion of patients with SpA have been immunized to the subcutaneous anti-TNF drug they are using. Concomitant use of MTX protects from immunization, whereas SASP does not. Patients with SpA using subcutaneous anti-TNF drugs can benefit from monitoring of the drug trough levels. Immunization to biological drugs can lead to decreased efficacy and increased risk of adverse effects. The objective of this cross-sectional study was to assess the extent and significance of immunization to subcutaneous tumor necrosis factor (TNF) inhibitors in axial spondyloarthritis (axSpA) patients in real-life setting. A serum sample was taken 1-2 days before the next drug injection. Drug trough concentrations, anti-drug antibodies (ADAb) and TNF-blocking capacity were measured in 273 patients with axSpA using subcutaneous anti-TNF drugs. The clinical activity of SpA was assessed using the Bath AS Disease Activity Index (BASDAI) and the Maastricht AS Entheses Score (MASES). ADAb were found in 11% of the 273 patients: in 21/99 (21%) of patients who used adalimumab, in 0/83 (0%) of those who used etanercept, in 2/79 (3%) of those who used golimumab and in 6/12 (50%) of those who used certolizumab pegol. Use of methotrexate reduced the risk of formation of ADAb, whereas sulfasalazine did not. Presence of ADAb resulted in decreased drug concentration and reduced TNF-blocking capacity. However, low levels of ADAb had no effect on TNF-blocking capacity and did not correlate with disease activity. The drug trough levels were below the consensus target level in 36% of the patients. High BMI correlated with low drug trough concentration. Patients with low drug trough levels had higher disease activity. The presence of anti-drug antibodies was associated with reduced drug trough levels, and the patients with low drug trough levels had higher disease activity. The drug trough levels were below target level in significant proportion of patients and, thus, measuring the drug concentration and ADAb could help to optimize the treatment in SpA patients.

Three out of four disease-modifying anti-rheumatic drug-naïve rheumatoid arthritis patients meet 28-joint Disease Activity Score remission at 12 months: results from the FIN-ERA cohort.

OBJECTIVE: To assess what proportion of patients with disease-modifying anti-rheumatic drug (DMARD)-naïve early rheumatoid arthritis (ERA) reach 28-joint Disease Activity Score (DAS28) remission over 1 year, and remission variability across clinics in Finland. METHOD: Patients with DMARD-naïve newly diagnosed inflammatory arthritis were recruited. The proportion of patients in 28-joint Disease Activity Score with three variables (DAS28-3) remission was compared across sites. Repeated measures were analysed using a mixed models approach with appropriate distribution and link function. RESULTS: In total, 611 patients were recruited at five sites: 67% were female; the mean (sd) age was 57 (16) years; 71% and 68% were positive for rheumatoid factor and anti-cyclic citrullinated peptides, respectively; and 23% had radiographic erosions. A total of 506 (83%) fulfilled the American College of Rheumatology/European League Against Rheumatism 2010 classification criteria for rheumatoid arthritis for further analyses. DAS28-3 remission was met by 68% and 75% at 3 and 12 months, respectively. The clinical site had no effect on remission when adjusted for confounders. At baseline, 68% used methotrexate-based combination therapy, and 31% used triple therapy with methotrexate, hydroxychloroquine, and sulphasalazine (the Fin-RACo regimen). In multivariate analysis, the only independent predictors of DAS28-3 remission at 12 months were lower baseline DAS28-3 and triple therapy as the initial treatment. CONCLUSION: Three out of four DMARD-naïve ERA patients in Finland are in remission during the first year from the diagnosis. High remission rates were achieved for most patients with the use of conventional synthetic DMARDs in combination. Treatment of DMARD-naïve ERA patients with the FIN-RACo regimen is a predictor of DAS28-3 remission in real-life rheumatology settings.

Drug survival on tumour necrosis factor inhibitors in patients with rheumatoid arthritis in Finland.

OBJECTIVE: A systematic review found that an average of 27% of rheumatoid arthritis (RA) patients using tumour necrosis factor (TNF) inhibitors discontinue their treatment within 1 year. The aim of this study was to assess drug survival on TNF inhibitors among patients with RA. METHODS: Patients were identified from the National Register for Biologic Treatment in Finland (ROB-FIN), which is a longitudinal cohort study established to monitor the effectiveness and safety of biologic drugs in rheumatic diseases. Inclusion was limited to TNF-inhibitor treatments started as the patient's first, second, or third biologic treatment between 2004 and 2014. Follow-up was truncated at 36 months. The results of a time-dependent Cox proportional hazards model were reported as adjusted hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: Of the 4200 TNF-inhibitor treatment periods identified from ROB-FIN, 3443 periods from 2687 patients met the inclusion criteria. Twenty-seven per cent of the patients discontinued their treatment within 12 months. Infliximab (HR 1.8, 95% CI 1.3-2.5) and certolizumab pegol (HR 1.7, 95% CI 1.2-2.3) had lower drug survival compared to golimumab. A similar trend was seen with adalimumab (HR 1.2, 95% CI 0.90-1.7) and etanercept (HR 1.2, 95% CI 0.87-1.6). Concomitant use of methotrexate (MTX) was associated with improved drug survival (HR 0.76, 95% CI 0.64-0.90) in comparison with TNF-inhibitor monotherapy. CONCLUSIONS: Golimumab was better in terms of drug survival than infliximab or certolizumab pegol and at least as good as adalimumab and etanercept. Concomitant use of MTX improved drug survival on TNF inhibitors.

Classic disease modifying anti-rheumatic drugs (DMARDs) in combination with infliximab. The Finnish experience.

To assess the performance of infliximab in a clinical setting, 364 rheumatoid arthritis (RA) patients from the National Register of Biological Treatment in Finland (ROB-FIN) were analysed. Corticosteroid usage and dose diminished (p<0.05 and 0.001, respectively) in patients on infliximab, of whom 51% also used one, 28% two and 16% three other concomitant DMARDs. A 34% of the RA patients used methotrexate+/-corticosteroids without any other DMARD. Methotrexate was most frequently used with sulphasalazine and/or hydroxychloroquine. Non-methotrexate patients most frequently used leflunomide or azathioprine combined with corticosteroids. The clinical effect of these combinations was similar to that of infliximab with methotrexate alone. The results indicate that infliximab can be used together with other DMARDs than methotrexate alone, quite according to the philosophy of the combination drug therapy, as the effectiveness is as good as or even slightly better than that of methotrexate and infliximab.

Effect of a three month course of ciprofloxacin on the late prognosis of reactive arthritis.

BACKGROUND: The value of antibiotics in the treatment of reactive arthritis (ReA) is still controversial. OBJECTIVES: To analyse the long term outcome of patients with ReA, treated with a three month course of ciprofloxacin or placebo. METHODS: Patients who had had ReA and had participated in a double blind, placebo controlled trial on the effectiveness of ciprofloxacin 4-7 years earlier were invited to a clinical examination. Of the 71 patients who were included in the original study, 53 agreed to visit the clinic for an examination. Twenty six of 53 patients had originally received ciprofloxacin and 27 had belonged to the placebo group. Of these, 20 in the ciprofloxacin and 25 in the placebo group were HLA-B27 positive. RESULTS: 11/27 (41%) patients in the original placebo group had now developed chronic rheumatic disease, as compared with only 2/26 (8%) patients originally treated with ciprofloxacin (p=0.006). Two patients who originally had received placebo, none in the ciprofloxacin group had developed ankylosing spondylitis, and three patients in the original placebo group, none in the ciprofloxacin group had recurrent anterior uveitis. The same tendency was seen when several different measures were analysed. Of the patients with chronic spondyloarthropathy, 10 in the placebo and none in the ciprofloxacin group were HLA-B27 positive. CONCLUSION: Analysis 4-7 years after the initial ReA suggests that a three month course of antibiotics in the acute phase may have a beneficial effect on the long term prognosis.

Effects of short-term lamotrigine treatment on pharmacokinetics of carbamazepine.

AIM AND METHOD: The effects of short-term treatment with lamotrigine (LTG) (100 mg twice daily for one week) on single dose pharmacokinetics of carbamazepine (CBZ, 200 mg) were investigated in a randomized, double-blinded, placebo-controlled cross-over study with 10 healthy volunteers. RESULTS: Pharmacokinetic parameters for CBZ or for CBZ-10,11-epoxide, the main metabolite of CBZ, were not significantly affected by LTG pretreatment. The mean (+/- SEM) elimination half-life of CBZ was 33.0+/-1.8 h after pretreatment with placebo and 30.1+/-2.0 h after a one-week-pretreatment with LTG (NS). The area under the serum concentration curve to infinity (AUC) of CBZ was 638+/-45 micromol/l after placebo and 624+/-53 micromol/l after LTG (NS). Changes in the peak serum concentration, from 9.0+/-0.3 micromol/l to 9.2+/-0.4 micromol/l (LTG), and in the time to peak serum concentration, from 9.3+/-1.1 h to 9.1+/-1.2 h (LTG), were also not significant. CONCLUSION: These data support the earlier findings that LTG does not significantly affect the rate or extent of absorption, or elimination of CBZ.

Effect of a three month course of ciprofloxacin on the outcome of reactive arthritis.

BACKGROUND: Treatment of reactive arthritis (ReA) with antibiotics has so far remained controversial. Eradication of the causative microbe appears logical, but short term antibiotic treatment has no beneficial effect on the outcome of ReA. OBJECTIVE: To evaluate the effect of a three month course of ciprofloxacin on ReA. METHODS: In a randomised, double blind, placebo controlled trial, between December 1992 and February 1996, 71 patients with acute ReA triggered by a gastrointestinal or a urogenital infection were randomly assigned to receive ciprofloxacin 500 mg or placebo twice daily for three months. Patients were assessed at study entry, at 6 weeks, 3 months, 6 months, and 12 months. Sixty two patients were valid for the efficacy analysis. The primary outcome measures were erythrocyte sedimentation rate, number of swollen joints, patients self assessment, and complete recovery. RESULTS: Adverse events were mostly mild and occurred in both treatment groups. There were no statistically significant differences in any of the primary or secondary efficacy variables between the study groups at baseline or during the 12 month follow up. All primary outcome measures indicated that the condition of the patients improved during the study. CONCLUSION: Both groups tended to recover. Ciprofloxacin, given as a three month course, had no advantage over placebo treatment.

Normal T-helper 1/T-helper 2 balance in peripheral blood of coeliac disease patients.

Activated T cells, with their secretion of cytokines, probably play an important role in the pathogenesis of mucosal lesions in coeliac disease (COD) and the prominence of a T-helper (Th)1-type cytokine pattern has been reported. As the process of immunological activation in the jejunal mucosa in active CoD has been shown to also cause some differences in peripheral blood lymphocyte populations, we sought to establish any changes in the Th 1/Th2 balance in peripheral blood of patients, at different stages of CoD, relative to healthy individuals. Twenty-two CoD patients and 10 healthy controls were included in the study. The Th1/Th2 balance was examined both in resting cells and after polyclonal stimulation using two different methods: intracytoplasmic cytokine contents were measured using an intracellular staining method and three-colour flow cytometry and cytokine contents of cell culture supernatants were measured using traditional enzyme-linked immunosorbent assays (ELISAs). Interferon-gamma (IFN-gamma)-producing cells (Thl) were as prominent in untreated CoD patients and treated CoD patients as in healthy controls, while cells fitting a Th2 or ThO-type cytokine pattern were few in all groups. In ELISA assays, Th1 type (IFN-gamma or interleukin (IL)-2) cytokines were again prominent in all study groups but no statistically significant differences were found in IFN-gamma, IL-4 or IL-2 levels among the three groups. These results suggest that the increased shift towards a Th1 response is mainly restricted to the actual site of inflammation and that circulating T cells do not show a similar response, presumably because activated cells in peripheral blood are too few. Further research on cytokine profiles measuring T-cell activation in CoD should be focused on the actual tissue of inflammation.

Amrinone, a phosphodiesterase III inhibitor, and arachidonic acid metabolism in humans.

Amrinone-a phosphodiesterase III inhibitor-is used in the treatment of acute heart failure. In addition to its hemodynamic effects, amrinone has been shown to inhibit thromboxane synthesis in vitro. We investigated the effects of amrinone on thromboxane, prostaglandin, and leukotriene synthesis in humans. Eight healthy male volunteers took part in this single-blind study in which either amrinone (a 1.5-mg/kg bolus in 30 min and after that 10 microg/kg/min for 1 h 30 min) or placebo (0.9% NaCl) were infused. Amrinone infusion increased systolic blood pressure but had no significant effect on diastolic blood pressure or heart rate. Amrinone did not modulate thromboxane B2 synthesis stimulated by either spontaneous clotting or calcium-ionophore A23187 in whole blood. Amrinone had no effects on prostaglandin E2 or leukotriene E4 production in A23187-stimulated whole blood, nor did it affect urinary excretion of 11-dehydrothromboxane B2 or 2,3-dinor-6-keto-prostaglandin F1alpha, the index metabolites of thromboxane A2 and prostacyclin productions, respectively. We conclude that amrinone has no effects on eicosanoid production in humans at the dose level used in this study, and that the hemodynamic effects noticed are not mediated via cyclooxygenase or lipoxygenase products of arachidonic acid metabolism.

Circulating T lymphocyte subsets in coeliac disease (CoD) patients and healthy family members.

Increased proportions of circulating antigen-primed CD45RO+ TCR gammadelta cells have been found in untreated CoD patients. As certain immunological features are now found in both CoD and healthy persons carrying the HLA DQ2 heterodimer, we sought to establish whether healthy members of the families of CoD patients who are positive for HLA DQ2 and also have increased densities of TCR gammadelta intraepithelial lymphocytes (IEL) in their small bowel mucosa have elevated levels of circulating TCR gammadelta memory cells. Peripheral blood T cells were analysed by flow cytometry in 22 patients with CoD and 16 healthy family members. Untreated CoD patients had higher percentages of circulating CD45RO+ TCR gammadelta cells and CD45RO+ Vdelta1+ cells than healthy family members. On the other hand, the amount of circulating Vdelta1+ lymphocytes was lower in patients with CoD compared with healthy family members. In contrast, no differences were found between HLA DQ2+ and HLA DQ2- healthy family members in respect of circulating TCR gammadelta cell subsets. The change in circulating TCR gammadelta cell subsets found in patients with CoD is thus a consequence of an ongoing immunological process which diminishes on a gluten-free diet rather than a phenomenon directly caused by DQ2. These changes in peripheral blood are not found in healthy individuals who have the same HLA alleles DQA1*0501 and DQB1*0201 encoding the HLA DQ2 and who also have increased densities of TCR gammadelta IEL in their otherwise normal jejunal mucosa.

Different course of reactive arthritis in two HLA-B27 positive brothers with fatal outcome in one.

During an outbreak of Yersinia pseudotuberculosis III, one of two HLA-B27 positive brothers developed reactive arthritis (ReA), mild at first, but later severely destructive and ultimately fatal. The reactivation of ReA was possibly triggered by an oral polio vaccine. The cause of death was severe secondary amyloidosis. The other brother was exposed to the same Y. pseudotuberculosis strain but did not develop any disease during or after the outbreak. However, he later developed ReA due to a Salmonella infection, with a benign course.

Percutaneous transluminal angioplasty increases thromboxane A2 production in claudicants.

Percutaneous transluminal angioplasty is an acute, local stimulus to platelets which activation is regarded as an important factor for a later restenosis. The balance between the production of prostacyclin and thromboxane A2 is of (patho)physiological importance due to their opposite actions on vascular tone and platelet reactivity. In this study we investigated the influence of percutaneous transluminal angioplasty of the peripheral arteries on prostacyclin and thromboxane A2 productions in vivo by measuring the excretions of their urinary index metabolites, 2,3-dinor-6-ketoprostaglandin F1 alpha and 11-dehydrothromboxane B2, respectively, in 10 patients. We found a twofold increase in thromboxane A2, but no significant change in prostacyclin, production after peripheral transluminal angioplasty which shifted prostacyclin/thromboxane A2 balance to the direction of thromboxane A2 formation. This gives theoretical support to the use of thromboxane A2 synthase inhibitors and receptor antagonists as well as prostacyclin analogues in combination with peripheral percutaneous transluminal angioplasty to prevent thrombosis and restenosis.

Theophylline infusion modulates prostaglandin and leukotriene production in man.

Although theophylline has been used in the treatment of asthma for decades, it is not a first line choice any more. It is a well-known bronchodilator, but was recently discovered also to be an anti-inflammatory, immunomodulatory and bronchoprotective agent. Therefore we wanted to establish the role of theophylline on prostaglandin and leukotriene production, which plays a part in the pathogenesis of asthma. Theophylline was infused (bolus 5 mg/kg in 15 min and infusion 0.4 mg/kg/h for 1 h 45 min) into healthy volunteers. Thromboxane B2, prostaglandin E2 and leukotriene E4 were measured from the A23187-stimulated whole blood samples and stable metabolites of thromboxane A2; prostacyclin and leukotriene E4 were measured from urine. Theophylline increased prostaglandin E2 production and decreased leukotriene E4 production ex vivo in whole blood, thus increasing the prostanoid/leukotriene ratio. It did not change thromboxane B2 production stimulated by either spontaneous clotting or A23187 in the whole blood. Theophylline had hardly any effect on in vivo thromboxane, prostacyclin and leukotriene E4 production measured as urinary metabolites, 11-dehydro-thromboxane B2, 2,3-dinor-6-keto-prostaglandin F1alpha and leukotriene E4, respectively. Serum theophylline concentrations were at the lower level of normal therapeutic range during the infusion. The increase in PGE2 and the decrease in LTE4 synthesis ex vivo may offer a new explanation for the mode of antiasthmatic action of theophylline. It is notable that this phenomenon occurs at low serum theophylline concentrations. These results confirm the idea that theophylline has an anti-inflammatory and bronchoprotective action and support the use of theophylline as a therapeutic agent in asthmatic patients.

Prostacyclin and thromboxane A2 synthesis are increased in acute lower limb ischaemia.

Prostacyclin (PGI2) and thromboxane A2 (TXA2) play an important role in the pathophysiology of various cardiovascular diseases. The balance between PGI2 and TXA2 regulates the interaction between platelets and the vessel wall in vivo. In this study we measured PGI2 and TXA2 synthesis by analysing their urinary index metabolites 2,3-dinor-6-keto-PGF1 alpha and 11-dehydro-TXB2, respectively, in acute (10 patients) and chronic (10 patients) lower limb ischaemia. Both PGI2 and TXA2 synthesis were increased about two-fold in patients with acute lower limb ischaemia compared to chronic lower limb ischaemia. However, the PGI2/TXA2 ratio was more or less the same in acute and chronic lower limb ischaemia. In patients with acute lower limb ischaemia caused by thrombotic occlusion, PGI2 and TXA2 formation were about two times higher than in patients with acute lower limb ischaemia caused by embolic occlusion. Elevation of PGI2 and TXA2 synthesis in acute lower limb ischaemia may reflect increased platelet-vascular wall interactions without changing the PGI2/TXA2 ratio.

Distinct immunologic features of Finnish Sjögren's syndrome patients with HLA alleles DRB1*0301, DQA1*0501, and DQB1*0201. Alterations in circulating T cell receptor gamma/delta subsets.

OBJECTIVE: To determine whether there were differences in the circulating T lymphocyte subsets or clinical features of patients with primary Sjögren's syndrome (SS) who were positive for different HLA alleles. METHODS: Two- and three-color flow cytometry analyses were performed, using a whole blood lysing method. RESULTS: Patients with SS who had the HLA alleles DRB1*0301, DQA1*0501, and DQB1*0201 had lower levels of circulating V delta 1-positive T cell receptor gamma/delta (TCR gamma/delta) cells and higher levels of circulating CD45RO-positive TCR gamma/delta cells compared with patients with SS who did not have these alleles. The patient subgroup with these alleles also had higher levels of anti-SS-A/Ro and anti-SS-B/La. CONCLUSION: These results indicate that patients with primary SS may be immunologically divided into subgroups according to their HLA status. These immunologic changes in SS may also be typical of other autoimmune disorders in patients with the HLA-DR3 haplotype.

Effects of noradrenaline and dopamine infusions on arachidonic acid metabolism in man.

We infused noradrenaline (0.025 micrograms/kg/min for 60 min, n=7) and dopamine (3.0 micrograms/kg/min for 60 min, n=6) into healthy male volunteers to study the effects of these catecholamines on in vivo thromboxane A2, prostacyclin and leukotriene E4 production measured as urinary excretions of 11-dehydro-thromboxane (TX) B2, 2,3-dinor-6-keto-prostaglandin (PG) F1alpha and leukotriene (LT) E4, respectively. Plasma noradrenaline and dopamine concentrations were 2.9+/-0.3 and 233+/-17 nmol/l at the endo fo the noradrenaline and dopamine infusions, respectively. Noradrenaline decreased thromboxane production and increased leukotriene production almost two fold. It had hardly any effect on prostacyclin production. Dopamine had no significant effects on any of the variables, however, it had a tendency to increase prostacyclin and leukotriene production. The results indicate that noradrenaline is a more important modulator of arachidonic acid metabolism than dopamine in vivo.

Phenotypical characterization of peripheral blood T cells in patients with coeliac disease: elevation of antigen-primed CD45RO+ T lymphocytes.

Increased numbers of gamma delta T-cell-receptor-bearing (TCR gamma delta +) lymphocytes are present in the small intestinal epithelium of patients with coeliac disease (CoD). In this study the phenotypic characteristics of peripheral blood T cells from 14 untreated CoD patients and 14 healthy age- and sex-matched controls were determined with special emphasis on TCR gamma delta + lymphocytes. We also studied samples taken from 15 CoD patients who were on gluten-free diet (GFD). Two- and three-colour flow cytometry analyses were performed using a whole-blood lysing method. There was no significant difference between the percentages of TCR gamma delta + lymphocytes in patients and controls. However, the amount of delta TCS1+ lymphocytes was significantly lowered in untreated patients (0.48 +/- 0.42% in CoD versus 0.86 +/- 0.57% in controls, P < 0.05). The percentage of CD45RO+ T cells, which are a primed population of T cells including memory cells, was significantly raised in the peripheral blood of untreated patients. This phenomenon was most prominent within the TCR gamma delta + population (83.9 +/- 12.2% in CoD versus 65.5 +/- 14.7% in controls, P < 0.01), but the same applies to CD45RO+ TCR alpha beta + and delta TCS1+ T cells. In patients on GFD these changes seem to be at least partly corrected. Antigen-primed CD45RO+ T cells have been shown to accumulate in the jejunal epithelium of patients with untreated CoD. The enhanced 'memory activity' also found in the peripheral blood of untreated CoD patients may result from a continuous antigenic stimulus and this stimulus could be gluten triggered.

Noradrenaline and dopamine infusions modulate arachidonic acid cyclooxygenase and 5-lipoxygenase pathways ex vivo in man.

We have previously demonstrated that adrenaline infusion increases the thromboxane/leukotriene (TX/LT) ratio in whole blood in healthy volunteers. The aim of the present study was to see whether other catecholamines--noradrenaline and dopamine--are also capable of modulating arachidonic acid (AA) metabolism in man. Low doses of noradrenaline (0.025 microgram/kg/min) and dopamine (3.0 micrograms/kg/min), which did not change hemodynamics, were infused for 60 min into healthy male volunteers. Both dopamine and noradrenaline decreased TX synthesis stimulated by spontaneous clotting, but no remarkable effect was seen when calcium ionophore A23187 was used as a stimulus. Dopamine but not noradrenaline increased prostaglandin E2 (PGE2) synthesis in A23187-stimulated whole blood. They both marginally decreased LTB4 formation in A23187-stimulated whole blood. The findings indicate that not only adrenaline but also noradrenaline and dopamine modulate AA metabolism in man.

Ten-year follow up study of patients from a Yersinia pseudotuberculosis III outbreak.

A Yersinia pseudotuberculosis serotype III outbreak in 1982 was characterized by a high frequency of post-infectious complications. Ten years later 16 out of the 19 patients originally included in the outbreak were reached for a follow up evaluation. Altogether nine patients suffered from chronic joint symptoms. Four of them were HLA B27-positive. Two of these had ankylosing spondylitis; one with severe erosive polyarthritis and secondary amyloidosis which led to uremia requiring haemodialysis and eventually to death, the other with ankylosis of the lumbar spine and sacroiliitis. None of the patients any longer had detectable anti-Yersinia antibodies. The long-term prognosis of Yersinia-triggered reactive arthritis is discussed.

Sources of variation in the assessment of cell proliferation using proliferating cell nuclear antigen immunohistochemistry.

The reproducibility in quantitation of proliferation activity, determined using the monoclonal antibody 19A2 to proliferating cell nuclear antigen (PCNA), was tested in visual and computer-assisted analyses of brain tumor material. The PCNA labeling index was scored using count (PCNA-LI, visual and computer analyses) and area (PCNA-LIa, computer analysis) estimates of immunopositivity. The quality of immunostaining was the most important reason for variation in the assessment results. Other significant variation sources in the assessment were experience in selecting microscopic fields and distinguishing immunopositive nuclei from immunonegative ones. Computer-assisted analysis improved the reproducibility of quantitation between different observers (visual rPCNA-LI = 0.624 versus computer assisted rPCNA-LI = 0.904). Also, the use of PCNA-LIa improved the intraobserver and interobserver reproducibility in different stainings (observer 1:rPCNA-LI = 0.857 versus rPCNA-LIa = 0.874; observers 1 and 2: rPCNA-LI = 0.904 versus rPCNA-LIa = 0.927; observers 3 and 4: rPCNA-LI = 0.848 versus rPCNA-LIa = 0.906). PCNA-LIa by computerized image analysis improves accuracy in the evaluation of the granularly expressed PCNA level. Furthermore, the effect of tumor heterogeneity on the assessment results can be diminished with the computerized method because large tissue areas can be analyzed faster.