key: cord-014868-kg96uvpi
authors: Vita, S.; Dalessandri, A.; Alfonzetti, T.; Britti, D.; Boari, A.
title: Evaluation of Total Proteins and Serum Protein Fractions in Cats Naturally Infected by Leishmania infantum–A Preliminary Study
date: 2006
journal: Vet Res Commun
DOI: 10.1007/s11259-006-0073-1
sha: 
doc_id: 14868
cord_uid: kg96uvpi

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In canine leishmaniosis, laboratory parameters such as serum total proteins (TPs), albuminto-globulin (A/G) ratio, and single serum protein fractions have been proposed for their particular diagnostic significance and for monitoring the progress of the disease (Ceci and Petazzi, 1983; Bizzetti, 1998; Ciaramella and De Luna, 1999) . During the course of canine leishmaniosis, TPs may be mildly or remarkably increased or they may remain within normal ranges, depending on the degree of decrease in the serum albumin level. This decrease is often associated with βand γ-globulin increase, due to the activation of B-lymphocytes (Bungener and Mehlitz, 1977) , resulting in a reduction of the A/G ratio. Hypoalbuminemia may be the consequence of increased albumin loss secondary to glomerular or small bowel disorders (Ceci and Petazzi, 1983) , or decreased albumin synthesis because of chronic hepatic insufficiency (Bizzetti, 1998) . In canine leishmaniosis the electrophoretic pattern is often characterized by increased βand γ-globulin concentration. During the progress of feline leishmaniosis, some authors have observed increased serum TPs associated with hyper-γ-globulinemia and hypoalbuminemia with inversion of the A/G ratio and changes in the α-globulin fractions (Laurelle-Magalon and Toga, 1996 Hervas et al., 1999; Ozon et al., 1998; Pennisi, 2002; Poli et al., 2002) . According to other authors, serum protein concentration may be normal or only mildly changed in cats with leishmaniosis (Athias, 1991; Merchant and Taboada, 1995) . To the best of our knowledge, the evaluation of serum protein changes has only been reported once for a group of FIV infected cats positive to PCR assay for Leishmania infantum (Pennisi et al., 2000) . The objective of this study was to evaluate serum TPs and some protein fractions in cats positive to Leishmania.

The study was performed on 25 domestic shorthair cats (Group A), 16 females and 9 males, with an age ranging between 3 months and 16 years. All cats were positive to the indirect immunofluorescent antibody test (IFAT) for anti-L. infantum antibodies at the following titres: 1:40 (no. 16); 1:80 (no. 7); 1:160 (no. 1) and 1:320 (no. 1). A titre ≥ 1:40 was considered positive. All cats were also positive using a qualitative PCR assay for L. infantum on blood samples. Some cats were clinically asymptomatic (no. 10), while others showed moderate lymphadenomegaly (no. 5), anorexia and weight loss (no. 3), clinical signs related to chronic renal failure (no. 1), respiratory disorders (no. 4), chronic intestinal inflammatory disease (no. 1), and flea-bite hypersensitivity (no. 1). The control group included 25 cats (Group B) of different breeds, 15 females and 10 males, with an age ranging between 6 months and 15 years. These were clinically healthy and negative to the IFAT for L. infantum. Total proteins, albumin levels, A/G ratio, and protein electrophoresis were analysed on serum samples of both groups. Total proteins and serum albumin concentration were measured with an automated chemistry analyser (Olympus AU400), and electrophoresis and relative protein fractions were measured with an automatic instrument (Amplimedical Esprime72). Cats of both groups were also tested with an ELISA assay (SNAP Combo Plus R ) for the detection of FIV antibodies and FeLV antigens, and with an IFAT for Coronavirus antibodies. Results are expressed as mean ± SD and the 95% confidence interval (95%CI) was calculated for each parameter. The Student's t test for unpaired data (software GraphPad Prism 4.03) was employed to compare data observed in the two groups of cats. Furthermore, additional statistical comparison was made between seronegative cats (Group B) and subjects of Group A with equal titres of IFAT (1:40 and 1:80) for Leishmania, and between cats of Group B and clinically asymptomatic subjects of Group A . Significance was set at P < 0.05.

Cats belonging to both Group A and B were negative to FIV, FeLV and Coronavirus with the exception of 3 cats (12%) of Group A that tested positive for FIV and, therefore, were excluded from successive statistical analysis. Results of TPs, A/G ratio, and serum protein fractions, expressed as mean ± SD and 95%CI, are shown in Table I . Albumin concentration and A/G ratio were significantly lower (P < 0.0001), and γ-globulin concentration was significantly higher (P < 0.0001) for positive cats when compared to cats of the control group. The statistical comparison between the values of the 14 subjects positive to titre 1:40 and those of Group B showed the same level of significance observed between the entire Group A and Group B. The comparison between the 6 subjects positive to titre 1:80 and the values of Group B, resulted in statistically significant differences for the following: A/G (P < 0.0001), albumin (P < 0.01), α 1 -globulins (P = 0.047), α 2 -globulins (P = 0.024) and γ-globulins (P < 0.01). Furthermore, comparing the values of Group B with those of the clinically asymptomatic subjects of Group A (no. 10), statistically significant differences were obtained for the following parameters: A/G (P < 0.0001), γ-globulins (P < 0.0001), and albumins (P < 0.01). 

Our results showed that the modifications in TPs, A/G ratio, and serum protein electrophoresis in cats naturally infected with L. infantum, are similar to those observed in dogs with leishmaniosis (Bizzetti, 1998; Ceci and Petazzi, 1983; Ciaramella and De Luna, 1999) . Furthermore, seropositivity in cats seems to be associated with a decrease in the A/G ratio secondary to both hypoalbuminemia and hyper-γ-globulinemia. This finding is particularly relevant because it has also been observed in asymptomatic seropositive cats. The comparison among seronegative cats and cats of group A with different IFI titres showed that subjects with a titre of 1:40 had the same statistical significance of the entire Group A, whereas subjects with a titre 1:80 also had a higher level of both α 1 -globulins and α 2globulins when compared to the control group. Since the increase in α-globulin fraction is usually associated with an acute inflammation (Kaneko, 1997) , the variations found in subjects with different antibody titres may be due to a different stage of the infection, even though the subdivision of group A on the basis of a single dilution could seem arbitrary. By recruiting a higher number of seropositive cats more definitive data could be obtained. In addition, it will be necessary to collect follow-up data for these subjects to be able to assess the relationship between the modifications of the considered parameters and the course of the infection. In conclusion, the evaluation of different laboratory parameters has emerged as useful tool for addressing the diagnostic suspicion of L. infantum infection also in the cat, especially in areas endemic for leishmaniosis.

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