The frequency of occurrence of fish-shaped red blood cells in different haematologic disorders.

BACKGROUND: Red blood cells (RBC) resembling the silhouette of a fish are rarely observed in peripheral blood (PB) smears. In this study, we determined the frequency of occurrence of fish-shaped RBC in different haematologic diseases. METHODS: We examined PB smears of patients with iron deficiency anaemia (IDA) (n=23), ß-thalassaemia minor (BTM) (n=30), sickle cell disease (SCD) (n=7), autoimmune haemolytic anaemia (AIHA) (n=13), microangiopathic haemolytic anaemia (MAHA) (n=11), hereditary sphaerocytosis (HS) (n=4), hereditary elliptocytosis (HE) (n=3), vitamin B12 and folate deficiency (n=15), anaemia in liver disease (LD) (n=17), myelodysplastic syndrome (MDS) (n=15), acute myeloid leukaemia (AML) (n=29), chronic myeloid leukaemia (CML) (n=18), primary myelofibrosis (PMF) (n=12), chronic myelo-monocytic leukaemia (CMML) (n=15) and 21 healthy controls by light microscopy for the occurrence of fish-shaped erythrocytes. The fish-shaped RBC were counted as cells per 20 high-power fields (HPF) at 1000-fold magnification, and slides containing ≥1 fish-shaped RBC/20 HPF were regarded as positive. RESULTS: Fish-shaped RBC were significantly found in HE, iron deficiency, vitamin B12/folate deficiency, LD and PMF. The highest numbers of fish-shaped RBC were seen in HE and vitamin B12/folate deficiency. In patients with BTM, MDS, AML and CMML, this RBC anomaly was only occasionally observed. Furthermore, a statistically significant negative correlation of haemoglobin with the occurrence of fish-shaped RBC was apparent (p<0.014). CONCLUSIONS: Our data show that the occurrence of fish-shaped RBC is suggestive of a pathologic condition, especially IDA, HE, vitamin B12 or folate deficiency, primary mylofibrosis or LD, and is significantly associated with severity of anaemia.

Dacryocytes are a common morphologic feature of autoimmune and microangiopathic haemolytic anaemia.

BACKGROUND: Dacryocytes are teardrop-shaped erythrocytes which are most frequently observed in peripheral blood smears of patients with primary or secondary myelofibrosis as well as malignant infiltrative disorders of the bone marrow. Dacryocytes have rarely been described in blood smears of patients with autoimmune (AIHA) and microangiopathic haemolytic anaemia (MAHA). The clear prevalence of dacryocytes in AIHA and MAHA is unknown. METHODS: We compared the dacryocyte counts in blood smears stained according to the May-Grünwald-Giemsa technique between 20 subjects with AIHA and MAHA with those from 21 controls. The dacryocytes, defined as erythrocytes tapered to a point at one end, were counted as cells per 20 high power fields (HPF) at 630-fold magnification. RESULTS: In AIHA, MAHA and controls, dacryocytes were found in 89%, 91% and 19% of the slides, respectively. The rate of dacryocyte positivity and the dacryocyte counts between haemolytic anaemias and controls differed statistically highly significant (p<0.0001). CONCLUSIONS: The results of this study indicate that dacryocytes are commonly apparent in blood smears of patients with AIHA and MAHA. Knowledge of this frequent feature may be beneficial in clinical routine diagnosis.

The anti-VLA-4 antibody natalizumab induces erythroblastaemia in the majority of the treated patients with multiple sclerosis.

The presence of erythroblasts in the peripheral blood is generally associated with severe underlying disorders. The anti-very late antigen-4 (anti-VLA-4) antibody natalizumab, which is approved for treatment of multiple sclerosis, mediates an increase in circulating haematopoietic stem cells and may also trigger erythroblastaemia. We investigated the prevalence of erythroblastaemia in sequential blood smears of 14 natalizumab-treated and 14 interferon-treated patients with multiple sclerosis. Erythroblastaemia was found in 13 natalizumab-treated subjects (93%), whereas all controls were negative (p<0.0001). Knowledge of this frequent side effect is crucial for the correct interpretation of blood smears in natalizumab-treated patients and to avoid unnecessary diagnostic procedures.

Assessment of the response to acetylsalicylic acid in patients with myeloproliferative neoplasms by whole blood assays: a comparison of the PFA-100 with multiple electrode aggregometry.

Since thrombotic and haemorrhagic complications are the most important causes of morbidity and mortality in myeloproliferative neoplasms (MPN), establishing valid techniques for the monitoring of antiaggregatory treatment would be beneficial. The aim of this study was to assess the aspirin responsiveness in patients with MPN by multiple electrode aggregometry (MEA) and the PFA-100, to determine the concordance rate between the two techniques and to examine a potential clinical impact. Twenty-two consecutive outpatients with polycythaemia vera and essential thrombocythaemia receiving long-time treatment with 100 mg of aspirin were included and clinically re-evaluated within six months after study entry. All subjects were identified as aspirin responders using the PFA-100, whereas only nine (41%) study participants were detected as responders by MEA. The difference in the response rates was statistically highly significant (p < 0.0001). The median aggregation result was 55.5 U (8-123) in the ASPI test, and the median PFA-100 closure time (CT) was 300 sec (221 to 300) in the COL-EPI test. Within the clinical observation period no thrombotic or haemorrhagic events occurred in the study population. In this study we concluded that MEA and the PFA-100 are suitable devices for the detection of a response to aspirin treatment in patients with MPN, but differ significantly in the response rates and thus show a low concordance rate.

The detection of calcium pyrophosphate crystals in the synovial fluid of patients with rheumatoid arthritis using the cytospin technique: prevalence and clinical correlation.

There are only a few studies dealing with the detection and clinical impact of calcium pyrophosphate (CPPD) crystals in patients with rheumatoid arthritis (RA) published to date. In particular, data determined by the cytospin technique, which is an effective tool to enhance the crystal detection rate, are lacking. The objectives of this study were to determine the prevalence of CPPD crystals in the synovial fluid (SF) of patients with RA and to investigate whether the detection of CPPD crystals is correlated with demographic, clinical and serological features. We examined 113 consecutive SF samples of patients with RA, obtained from therapeutic arthrocentesis of knee joints. After cytocentrifugation, the sediments were examined by polarized microscopy for the occurrence of CPPD crystals. Demographic, clinical and serological data, acquired from the medical records, were compared between crystal-positive and crystal-negative subjects. CPPD crystals were observed in 20 of the 113 cases, representing 17.7%. CPPD-positive and CPPD-negative subjects did not differ significantly in sex, duration of disease, Steinbrocker radiologic stage, disease activity score 28, as well as serum rheumatoid factor and anti-CCP positivity. Patients positively tested for CPPD crystals had a significantly higher age than CPPD-negative patients (p < 0.0001). An age-independent association of long-time treatment with diuretics and CPPD crystal formation was not found. In conclusion, demographic, clinical and serological characteristics of patients with RA were not associated with the occurrence of CPPD crystals. Age was the only significant influencing factor on CPPD crystal formation in patients with RA.

The cytospin technique improves the detection of calcium pyrophosphate crystals in synovial fluid samples with a low leukocyte count.

In synovial fluids (SF) with low leukocyte or/and crystal counts, important features may be missed, if exclusively smears are examined by polarized microscopy. That may be overcome by cytocentrifuges, which use low-speed centrifugal force to concentrate cells onto a glass slide and thus enhance the number of cells per high power field (HPF). We compared the calcium pyrophosphate (CPP) crystal counts in cytospin preparations with those in common smears of SF. The number of CPP crystals was counted in 50 SF samples by polarized microscopy, and statistical comparisons of the mean values of the cytospin and smear preparations were performed using the Wilcoxon test. The reproducibility within the slides of the cytocentrifuge and smear samples was determined by Spearman's rank correlation. The crystal counts were significantly higher in the cytospin than in the smear preparations (median 96/10 HPF vs. 2.5/10 HPF, p < 0.0001). The correlation in the crystal count between the slides 1 and 2 was significantly higher within the cytocentrifuge than in the smear group (0.97 vs. 0.73, p = 0.0004). CPP-negative cytospin preparations in initially smear-positive slides were not observed. We confirmed that the cytospin technique significantly enhances the number of examinable crystals per HPF, compared to common smears.

Calcium pyrophosphate and monosodium urate crystals in synovial fluid as a cause of pseudoeosinophilia.

BACKGROUND: Synovial fluid (SF) leukocytes can be counted microscopically in a Neubauer chamber or by automated procedures using haematology analysers. Knowledge of laboratory artefacts is crucial for the correct interpretation of results obtained using automated methods. SF pseudoeosinophilia has recently been described as a new artefact in patients with crystal-related arthropathies. We investigated whether pseudoeosinophilia of SF is restricted to crystal-related disorders, or if it may also occur in other arthropathies. METHODS: We compared the percentages of eosinophils in 120 crystal containing SF samples with 185 crystal-free specimens using the Wilcoxon test. Crystal positive samples, determined by polarised microscopy, contained at least two monosodium urate or calcium pyrophosphate crystals per 10 high power fields (630× magnification). True SF eosinophilia was ruled out by microscopic examination of stained slides. RESULTS: Crystal positive samples had significantly higher percentages of eosinophils than the controls (p<0.0001). No significant differences between the two crystal types were found (p=0.693). Thus, pseudoeosinophilia was significantly correlated with the presence of crystals, and none of the distinct crystal types was more likely to be associated with pseudoeosinophilia. CONCLUSIONS: In this study, SF pseudoeosinophilia was confirmed as a crystal-related laboratory artefact which has to be considered in the interpretation of automated SF leukocyte differential counts.

Pseudoeosinophilia of synovial fluid is caused by crystals mimicking the distinct light scattering fractions of eosinophilic granules.

BACKGROUND: Automated leukocyte differential counts of synovial fluid (SF) can be influenced by laboratory artefacts. Pseudoeosinophilia of SF has recently been first described in association with monosodium urate and calcium pyrophosphate crystals. This study compared automated measurements of the percentages of SF leukocyte fractions by two haematology analysers in order to elucidate the underlying mechanism of pseudoeosinophilia. METHODS: The percentages of the leukocyte fractions of 17 crystal-containing and 28 crystal-free specimens were compared using the Wilcoxon test. Measurements were performed using the Cell-Dyn 3200 and the ADVIA 2120i, which are based on different techniques. RESULTS: The percentages of eosinophils of the crystal-positive samples determined by the Cell-Dyn 3200 were significantly higher than those assessed by the ADVIA (p<0.0001), whereas the percentages of eosinophils of the controls did not differ significantly between the two devices (p=0.95). The Cell-Dyn 3200 clearly showed the phenomenon of crystal-associated pseudoeosinophilia (p<0.0001), which did not occur in the ADVIA measurements (p=0.28). The percentage of neutrophils was to a lower degree elevated in the crystal group (p=0.015). CONCLUSIONS: It was confirmed that SF crystals interfere with the typical light scattering fractions of leukocyte granules and may thus lead to spuriously elevated percentages of eosinophils and neutrophils in SF specimens.

Cytospin preparations are superior to common smears in the detection of monosodium urate crystals in low-cellular synovial fluids.

In cases of gout with a low synovial fluid (SF) leukocyte count and atypical clinical presentation, such as in intercritical periods, the load of monosodium urate (MSU) crystals is frequently low, and thus, methods to improve the crystal detection may be beneficial. We compared the MSU crystal detection rates between cytospin slides and common smear preparations in low-cellular (<2,000/µl) SF samples of patients with gout. We determined the number of MSU crystals/15 high power fields (HPF) at × 1,000 magnification by polarised microscopy in cytospin preparations and smears in SF samples of 17 patients with MSU-crystal-proven gout and compared the two methods statistically. All of the cytospin slides (100 %) contained MSU crystals and showed a median number of 124 crystals/15 HPF (range 2-3,915), whereas 5 of the 17 smears (29 %) were MSU-crystal-negative, with a median count of 2 crystals/15 HPF (range 0-430/HPF). The difference was statistically highly significant (p < 0.0001). In conclusion, we have shown that the cytospin technique is superior to smears in the detection of MSU crystals in SF with a low SF leukocyte count. In light of our observations, we recommend the use of cytocentrifuges for routine crystal analysis in such cases.