Toxic Neutrophils in Cats: Clinical and Clinicopathologic Features, and Disease Prevalence and Outcome-A Retrospective Case Control Study

What we know about alterations in immune cells during sepsis in veterinary animals?

Sepsis is still one of the most common causes of death of animals and humans. It is marked by an aberrant immune response to infection, resulting in extensive inflammation, organ dysfunction, and, in severe instances, organ failure. Recognizable symptoms and markers of sepsis encompass substantial elevations in body temperature, respiratory rate, hemoglobin levels, and alterations in immune cell counts, including neutrophils, monocytes, and basophils, along with increases in certain acute-phase proteins. In contrast to human medicine, veterinarians must take into account some species differences. This article provides a comprehensive overview of changes in the immune system during sepsis, placing particular emphasis on species variations and exploring potential future drugs and interventions. Hence, understanding the intricate balance of the immune responses during sepsis is crucial to develop effective treatments and interventions to improve the chances of recovery in animals suffering from this serious condition.

Hypokalaemic myopathy associated with iatrogenic hypercorticism in a cat

Case summary

A 12-year-old castrated male domestic shorthair cat was referred for investigation of lethargy, hindlimb weakness with plantigrade stance and ventroflexion of the neck. The cat was fed a balanced diet and had received methylprednisolone acetate at a dose of 20 mg intramuscularly every 6 months for 6 years. On blood work, severe hypokalaemia and marked elevation of muscle enzymes were noticeable. The findings were suggestive of hypokalaemic myopathy. Urine fractional excretion of potassium (FEk) was moderately high (9.04%), and serum aldosterone was below the reference interval. An adrenocorticotropic hormone (ACTH) stimulation test was compatible with adrenal suppression. Upon hospitalisation, the patient was given intravenous (IV) Ringer lactate solution supplemented with potassium chloride and oral potassium citrate. The serum potassium concentration normalised by the fifth day of hospitalisation; therefore, IV potassium supplementation was suspended. The cat was discharged with oral potassium and the dose was gradually reduced over time. After 4 months, the cat was clinically normal; the serum potassium concentration remained within the normal range and the adrenal glands showed some response to ACTH stimulation. Potassium supplementation was therefore discontinued. One month later, the serum potassium concentration was still within normal limits and at the time of writing (7 months after presentation), no clinical signs had reoccurred.

Relevance and novel information

This report describes a case of hypokalaemic myopathy associated with iatrogenic hypercorticism in a cat. This condition was successfully treated with supplementation of potassium and a complete clinical remission was achieved within 4 months.

Left shift and toxic change in heterophils and neutrophils of non-mammalian vertebrates: A comparative review, image atlas, and practical considerations

Heterophils and neutrophils are important first cellular responders to inflammatory conditions. In addition to quantitative shifts in the numbers of these cells in blood, inflammatory disease states often have accompanying increases in immature precursor stages (left shift) and/or evidence of toxic change on blood film evaluation. Recognition of left shift and toxic change morphologies is a salient diagnostic finding with clinical relevance across species. The objectives of this report are to (a) review heterophil and neutrophil function and structure across the vertebrate animal kingdom, (b) compare morphologic features of left shift and toxic change in heterophils and neutrophils of non-mammalian vertebrates (NMV) to mammals, (c) provide an image guide demonstrating the breadth of morphologic diversity of heterophil and neutrophil lineages in health and disease across taxa, and (d) discuss practical considerations for clinical pathologists and other professionals involved in the recognition and interpretation of observations in the inflammatory leukogram of NMV.

Short Term Safety, Immunogenicity, and Reproductive Effects of Combined Vaccination With Anti-GnRH (Gonacon) and Rabies Vaccines in Female Feral Cats

Overpopulation of free-roaming cats is a major problem leading to negative impacts on animal health and welfare, public nuisance, transmission of zoonotic diseases, and well-documented harm to wildlife. Surgical sterilization had failed to provide a practical solution to free-roaming cats' overpopulation under field conditions; therefore, efficient and safe non-surgical immunocontraception methods are aspired. Rabies is a deadly virus that may infect people and animals. However, the safety and efficacy of combined vaccination with anti-GnRH and rabies vaccines in feral cats, which often suffer from disrupted health conditions and experienced high stress level, has never been studied. Therefore, our objective was to examine the short-term safety and efficacy of anti-GnRH vaccine (Gonacon), in combination with rabies vaccine in female feral cats. Mature feral female cats were captured and divided into the following groups: (I) GonaconX1-Rabies: queens vaccinated with both Gonacon and rabies (n = 5); (II) GonaconX2-Rabies: queens vaccinated twice with Gonacon (3 weeks apart) and with Rabies (n = 4); (III) OVx-Rabies: queens ovariohysterectomized and vaccinated with rabies (n = 4); (IV) Intact-Rabies: queens vaccinated against rabies and remained intact (n = 3). Comprehensive veterinary examinations and blood tests were performed every 2 weeks for 14 weeks. Data were analyzed by Repeated-Measures-ANOVA or Fisher-Exact-Test. There were neither systemic nor local adverse reactions at the vaccination sites. Blood count (PCV, TS, RBC, HGB, HCT, WBC) and chemistry (Total protein, Total globulin, Albumin, Urea, Creatinine, Creatine kinase, Bilirubin, GGT, ALT, AST) analyses revealed no differences among groups. There were no differences in serum rabies antibodies titers among groups, and queens kept a protective titer (>0.5 IU/mL) starting at 2–4 weeks after vaccination. Anti-GnRH antibodies were detected in all Gonacon-vaccinated queens, excluding one queen (GonaconX2-Rabies group). Anti-müllerian hormone serum concentrations reduced significantly after ovariohysterectomy, as well as gradually following vaccination with Gonacon, but it remained high in intact queens. Evaluation of vaginal cytology and ovarian histology suggested that reproductive cyclicity was suppressed in Gonacon-vaccinated queens. Our results support the conclusion that in the short term, the combined vaccination with Gonacon and rabies is safe and effective in female feral cats. However, further long-term studies are warranted to test this immunologic regimen in feral cats.

Intra- and inter-rater agreement for the detection of band neutrophils and toxic change in horses

BACKGROUND

The detection of band neutrophils and toxic change via microscopic blood smear review is vitally important, as their presence indicates systemic inflammation. However, in-clinic evaluation of WBC morphology is often limited.

OBJECTIVE

We aimed to determine the agreement between expert raters in the detection of bands and toxic change.

METHODS

Three board-certified clinical pathologists each evaluated 109 blood smears from horses with acute disease, and 19 control smears from healthy horses. The pathologists determined if bands were present, and if so, the percentage of bands present. They also determined if toxic change was present, and if so, the grade of toxic change. Intra-rater agreement was evaluated using 12 duplicate blood smears. Agreement on the presence of bands between pathologists and an in-clinic hematology analyzer was evaluated.

RESULTS

Intra-rater agreement was substantial to almost perfect. Agreement between pathologists for the detection of bands was moderate, but when pathologists agreed bands were present, there was excellent agreement on the percentage of bands and mature neutrophils. Agreement between pathologists for the detection of high-grade, clinically relevant toxic change was fair. When pathologists agreed high-grade toxic change was present, there was fair agreement on Döhle bodies and cytoplasmic basophilia and poor agreement on cytoplasmic vacuolation. Agreement between individual pathologists and the in-clinic hematology analyzer for the indication of bands was fair to moderate.

CONCLUSIONS

Consistent identification of bands and toxic change is challenging, even for highly trained personnel. It is, thus,not surprising that in-clinic blood smear evaluation of WBC morphology by non-experts could be inadequate.

Effect of time and storage on toxic or pseudo-toxic change in canine neutrophils

BACKGROUND

The presence of toxic change in neutrophils is frequently used as a biomarker of inflammation in dogs.

OBJECTIVE

We aimed to evaluate the effect of time and storage on toxic change in canine neutrophils.

METHODS

One hundred and fifty microliters of EDTA blood were obtained from eight dogs with no toxic neutrophil changes observed on fresh blood smears (T0). Blood was stored at room temperature (RT), in a box with an icepack (ICE), and at 4°C. For each storage condition, smears were prepared 2 (T2), 4 (T4), 8 (T8), and 24 (T24) hours post blood draw. Smears were randomized, and each smear was evaluated for the presence of toxic neutrophil change.

RESULTS

A statistically significant effect of time and storage on the presence of toxic neutrophil change was observed. Compared with T0, the number of neutrophils containing Döhle bodies was significantly higher at T8 and T24 for the RT (P < 0.0001) and ICE (P < 0.0001) samples and at T24 for 4°C samples (P < 0.0001). Additionally, smears were falsely classified as having 1+ toxic change in 0/8 (T2), 1/8 (T4), 3/8 (T8), and 8/8 (T24) for RT samples; 0/8 (T2 and T4), 2/8 (T8), and 5/7 (T24) smears for ICE samples; and 0/8 (T2, T4, and T8) and 2/8 (T24) for 4°C samples.

CONCLUSIONS

Smears can be falsely classified as having neutrophils with toxic change as early as 4 hours post blood draw in samples stored at RT, 8 hours when stored with icepacks, and 24 hours when stored at 4°C. Canine blood smears should be prepared and evaluated for toxic neutrophil change as early as possible.

Association of Presence of Band Cells and Toxic Neutrophils with Systemic Inflammatory Response Syndrome and Outcome in Horses with Acute Disease

BACKGROUND

Band cells and toxic neutrophils are thought to indicate acute and severe systemic illness but no studies have investigated their importance in adult equine emergency admissions.

OBJECTIVES

The objective of this study was to evaluate the association of band cells and toxic neutrophils with systemic inflammatory response syndrome (SIRS) and outcome in horses.

ANIMALS

One hundred and five adult horses admitted on emergency basis to a private primary referral practice.

METHODS

Prospective observational study with sample collection. All horses admitted on emergency basis over the study period were included in the study if they had a CBC and a blood smear collected on admission.

RESULTS

The detection of band neutrophils on admission was associated with the SIRS status of the horse (RR = 2.80; 95% CI = 1.57-4.99; P < .001) and with poor outcome (RR = 1.88; 95% CI: 1.05-3.37; P = .038). Similarly, the presence of a neutrophil toxic grade higher than 3 was associated with SIRS (RR = 1.71; 95% CI: 1.03-2.82; P = .034) and death (RR = 2.34; 95% CI: 1.22-4.50, P = .007). The information gained from the blood smear review could not be captured by looking at only the WBC or neutrophil count.

CONCLUSIONS AND CLINICAL IMPORTANCE

The microscopic review of blood smears from critically ill horses to detect band cells or neutrophil toxic change is valuable and could help in assessing disease severity and prognosis in adult equine emergency admissions.