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PubMed2000

A new four-color flow cytometric assay to detect apoptosis in lymphocyte subsets of cultured peripheral blood cells.

BACKGROUND: Human peripheral blood lymphocytes kept in culture after isolation die by an apoptotic process. Detection of apoptosis with labeled Annexin V to demonstrate loss of plasma membrane asymmetry is sensitive, specific, and easy using flow cytometry. This is true in lymphoblastic cell lines when combining Annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI). However, measurement of apoptosis by flow cytometry in isolated human lymphocytes using Annexin V-FITC/PI is disturbed by the presence of a variable percentage of erythrocytes in the isolated lymphocyte population. To overcome this problem, we have developed and tested a new four-color flow cytometric assay to detect apoptosis in lymphocyte subsets of cultured peripheral blood cells. METHODS: Peripheral blood lymphocytes are isolated by density gradient centrifugation. Nucleus-containing cells are selected using CD45-phycoerythrin (PE). The lymphocyte subset of interest is selected using CD4, CD8, or CD19 energy-coupled dye (ECD) labeling. Apoptosis is detected using Annexin V-FITC with 7-amino-Actinomycin-D (7-AAD) to distinguish early apoptotic from late apoptotic lymphocytes. RESULTS: We have developed a new technique to detect apoptosis in isolated human peripheral blood lymphocyte subsets with good reproducibility, coefficient of variation < 17%. CONCLUSIONS: We now have a validated tool to study apoptosis in subsets of isolated human lymphocytes to increase our knowledge of pathogenesis and therapies in lymphoreticular malignancies.

Annexin A5↗

PubMed2006

[Analysis of serum T-lymphocyte subsets and NK cell activity in patients with hypopharyngeal squamous cell carcinoma].

BACKGROUND & OBJECTIVE: T-lymphocyte subsets and NK cell are the major forms of cellular immunity. Study of these 2 types of cells may lead to the better understanding of the function of cellular immunity in the onset and development of carcinoma. To a certain degree, there may be cellular immunodeficiency existing in patients with hypopharyngeal squamous cell carcinoma. This study was to investigate the cellular immunity function in these patients. METHODS: T-lymphocyte subsets and NK activity were determined by flow cytometry in 78 patients with hypopharyngeal squamous cell carcinoma. Blood samples of 20 non-tumor patients were used as control. RESULTS: The levels of CD4 lymphocyte subsets, CD4/CD8 ratio, and NK activity were lower in carcinoma group than in control group, but CD8 lymphocyte level was higher in carcinoma group. The levels of CD4 lymphocyte subsets, CD4/CD8 ratio, and NK activity were lower in T3-4 group than in T1-2 group, and lower in N+ group than in N0 group. The levels of CD4 lymphocyte subsets and CD4/CD8 ratio were decreased in the carcinoma with moderate or low differentiation (P<0.05). CONCLUSIONS: T-lymphocyte subsets and NK activity are inhibited, and the cellular immunology is suppressed in the patients with hypopharyngeal squamous cell carcinoma. Analyzing T-lymphocyte subsets and NK activity would be helpful to evaluate the cellular immunologic condition of these patients.

Adult↗

PubMedDate not supplied

Peripheral blood lymphocyte subsets in healthy Turkish children.

Immunophenotyping of peripheral blood lymphocyte subpopulations is essential for the diagnosis and follow-up of children with immunodeficiencies and other immune disorders. The relative size and absolute number distributions (median and 5-95%) of lymphocyte subsets, including cord blood (Coulter, EPICS-XL) were examined by flow cytometry in 190 healthy subjects from birth to 18 years of age with a view to obtaining normal reference values for Turkish children of the following age groups: cord blood (n:29), birth to 1 year (n:41), 1 to 2 years (n:30), 2 to 6 years (n:30), 6 to 10 years (n:30), and 10 to 18 years (n:30). The relative size of CD2+, CD3+CD16-56-, CD3+CD8+ T lymphocytes increased while the relative size and absolute counts of those together with CD3+CD4+ and CD19+, CD20+ B lymphocytes decreased with age. The percentage of CD3-CD16+56+ NK cells increased from 0-1 year to 10-18 years; however, absolute count of CD3-CD16+56+ NK cells remained stable and unchanged in all age groups. The relative size and absolute count of activation markers (CD3+CD25+ and HLADR+) decreased from 0-1 year through 10-18 years age group. This study has once more demonstrated that both the percentage and the absolute number of lymphocyte subsets in cord blood and peripheral blood of healthy infants and children changed with age. Therefore, comparison of results to those of age-matched healthy controls is of utmost importance in the reliable and accurate evaluation of lymphocyte subsets reflecting cellular immunity in children.

Adolescent↗

PubMed1994

Circannual variation in lymphocyte subsets, revisited.

BACKGROUND: Circadian and circannual variations in lymphocyte subsets, especially CD8+ T-lymphocytes, have been reported. This study focuses on CD4+ T-lymphocyte seasonal variation over a 6-year 8-month period. STUDY DESIGN AND METHODS: Lymphocyte subsets were quantitated monthly for four healthy individuals from 1986 through 1992 as part of a flow cytometry quality-control program. RESULTS: In general, there were no significant seasonal changes in the total number of white cells or in total lymphocyte counts. The absolute numbers of CD4+ T-lymphocytes were lowest in summer when the CD8+ T-lymphocytes were highest. Mean CD4+ T-lymphocyte counts were 846, 967, 618, and 695 per microL for Subjects 1 through 4, respectively, in winter and 432, 670, 355, and 766 per microL, respectively, in summer. Two healthy subjects had CD4+ T-lymphocyte counts lower than 300 per microL on one or more occasions during the study period. In three of the four subjects, the percentage of B-lymphocytes in winter was almost double that in summer. In one of the four subjects, no circannual rhythm was observed in these lymphocyte subpopulations. CONCLUSION: The seasonal variation in CD4+ T-lymphocyte counts demonstrated in three healthy individuals over almost 7 years is again of interest in light of renewed consideration of using surrogate tests, such as CD4+ T-lymphocyte counts, to screen for AIDS-like diseases that may be in the blood supply.

Adult↗

PubMed1983

Delineation of suppressor and helper activity within the OKT4-defined T lymphocyte subset in human newborns.

Lymphocytes taken from the cord blood of newborns have active suppressor activity. Using in vitro PWM-stimulated cocultures, unfractionated T cells from newborns potently suppressed the expected immunoglobulin G (IgG) synthesis of their mothers' peripheral blood lymphocytes (PBL). Using positive and negative selection techniques, we characterized the active suppressor cell as expressing the OKT4+T8- phenotype. This cord blood lymphocyte subset suppressed maternal IgG synthesis after depletion of maternal suppressor cells, implicating the ability of newborn T cells to suppress directly rather than by inducing adult suppressor activity. Sublethal amounts (1500 rad) of gamma-irradiation fully abrogated the suppressor activity of cord blood T lymphocytes. Radioresistant cord T cells provided T cell help. Irradiation of cord OKT4+ and OKT8+ populations and their subsequent culture with maternal B cells determined that helper activity was a radioresistant subpopulation of the OKT4+ subset. These results indicate significant differences in the functional properties of T cell subsets from adults and newborns. Population studies determined that cord blood lymphocytes had a greater proportion of OKT4+ cells and lower proportion of OKT8+ cells than PBL from unrelated adults. The mothers tested had similar proportions of OKT4+ cells as their babies, and these levels are significantly higher than those of unrelated adults.

Adult↗

PubMed1982

Distribution of T lymphocyte subsets in human colostrum.

Lymphocytes were isolated from human colostrum and peripheral blood collected within 7 days postpartum. A 20-fold enrichment of lymphocytes from colostrum was achieved by centrifugal elutriation followed by equilibrium density gradient centrifugation. The distribution of T lymphocyte subsets was determined by immunofluorescence analysis of reactivity with monoclonal antibodies of the OKT series. In confirmation of previous reports employing sheep erythrocyte rosette assays, the majority of colostral lymphocytes reacted with OKT3 monoclonal antibody, a reagent that detects a surface antigen on mature T cells. Neither colostral nor blood lymphocytes from postpartum donors expressed the OKT6 antigen that is found in immature thymocytes. A novel finding is that the T lymphocyte population in colostrum contains both OKT4 (helper/inducer phenotype) and OKT8- (cytotoxic/suppressor phenotype) positive subsets. The relative ratio of OKT4 to OKT8-positive T cell subsets in colostrum, however, is generally lower than that observed for peripheral blood T cells.

Antibodies, Monoclonal↗

PubMed1993

Respiratory symptoms, lung function tests, airway responsiveness, and bronchoalveolar lymphocyte subsets in B-chronic lymphocytic leukemia.

A respiratory questionnaire was completed and spirometry, tests for lung volumes, diffusion capacity for CO, and methacholine bronchial challenge were performed in 24 outpatients with B-chronic lymphocytic leukemia (B-CLL), aged 44-79, presenting in different stages of their disease. In 10 patients, bronchoalveolar lavage (BAL) fluid was also obtained. Ten of twenty-four patients had symptoms consistent with chronic bronchitis, unrelated both to smoking history and to the clinical stage. Abnormal values (< 2 SD) were found in 4 patients for total lung capacity (TLC), in 9 for vital capacity (VC), 8 for forced expiratory volume in 1 sec (FEV1), 11 for MEF50, 15 for MEF25 and in 7 for diffusing capacity for carbon monoxide. Seven of nineteen patients had PD20FEV1 at less than 1,600 micrograms of methacholine chloride. There was a significantly negative correlation between white blood cell count and VC (r = 0.41, P < 0.05). A positive correlation was found between PD20FEV1 and FEV1/VC (r = 0.61, P < 0.01). The mean and SEM for BAL cells/ml was 463 (71.8) x 10(3). No leukemic cells but a marked increase in T lymphocytes (32.5 +/- 7.8%) were found in BAL fluid. There were significantly negative correlations between the number of BAL CD3+ T lymphocytes and PD20FEV1 (r = 0.61, P < 0.05), and between the number of BAL CD8+ T lymphocytes and PD20FEV1 (r = 0.84, P < 0.01). In conclusion, patients with B-CLL have a high prevalence of respiratory symptoms, small airway dysfunction and CD8 "alveolitis" related to airway responsiveness; despite the well-known lung interstitial lymphocyte infiltration in B-CLL, leukemic cells are not found in BAL fluid.

Adult↗

PubMed1988

Modification of lymphocyte subsets in Jessner's lymphocytic infiltration of the skin during proquazone treatment.

This study deals with 13 patients who volunteered for serial biopsies during proquazone treatment which proved to be effective in the majority of the cases. The immunocompetent cells in the inflammatory cell infiltrates were characterized by a panel of monoclonal antibodies: OKT11, OKT4, OKT8, OKT6, NK-9 and Leu-14. Before proquazone treatment there was only a slight predominance of OKT4-positive cells as compared to OKT8-positive cells but a rather high number of NK-9-positive natural killer or activated cytotoxic T cells. The pattern of inflammatory cell subclasses changed during the treatment and the most striking difference was the reduction in the number of the NK-9-positive cells. It is proposed that Jessner's lymphocytic infiltration of the skin (LIS) should be viewed as an entity and that proquazone possibly acts by modulating the pattern and activation stage of lymphocyte subclasses in LIS.

Adult↗

PubMed2004

Total and subset lymphocyte counts, angiotensin converting enzyme inhibitors, and dialysis duration in younger and older peritoneal dialysis patients.

Disturbances in immunity and nutrition status worsen in peritoneal dialysis (PD) patients with advancing age. In the present study, we evaluated variations in total lymphocyte count (TLC) and subset lymphocyte counts (SLCs) with respect to the age of PD patients. We carried out the study in two groups of PD patients. Group I patients (n = 12) were less than 40 years of age (35.5 +/- 5.4 years), and their PD duration was 18.2 +/- 9.4 months. Group II patients (n = 14) were more than 60 years of age (67.2 +/- 5.1 years), and their PD duration was 20.6 +/- 11.0 months. In group I, 9 patients were taking angiotensin converting enzyme inhibitors (ACEIs); in group II, 10 patients were taking ACEIs. We used flow cytometry to estimate SLCs (determining CD3, CD4, CD8, CD19, and CD16+56 antigens). In both groups, the mean CD19, CD4, and CD8 counts were lower than the normal ranges. In group II, TLC and CD3 count were also lower than normal. In group I, correlations were seen between age and TLC, CD3, CD19, CD4, and CD8. Correlations were also seen between dialysis duration and TLC, CD3, CD19, and CD4, and between total ACEI dose and CD19 count. In group II, correlations were seen between age and TLC, CD3, and CD8. No correlation was observed between PD duration and TLC or SLCs, but a correlation between total ACEI dose and CD8 count was seen. In patients who were taking enalapril as their only ACEI, a correlation was observed between total enalapril dose and TLC, CD3, and CD8. Our results confirm data that indicate worse immunity and nutrition status in older PD patients and demonstrate decreasing values of TLC and SLCs with aging in younger and older PD patients alike. Administration of ACEIs negatively influences SLCs independently of age, but decreases in TLC and SLCs are significantly related to PD duration only in younger patients.

Adult↗

PubMed2000

Hyperbaric stress during saturation diving induces lymphocyte subset changes and heat shock protein expression.

To clarify the cellular responses and biochemical markers of hyperbaric stress, we investigated heat shock protein (hsp) expression and subset changes of human peripheral blood lymphocytes during saturation diving. Five healthy male subjects underwent a 39-day saturation dive to the maximal storage pressure of 4.1 MPa [400 meters of sea water (msw)]. During the saturation dive, lymphocyte subset changes were detected using a flow cytometer, and increased expressions of hsp 72/73 and hsp 27 were observed by Western blot analysis. Lymphocyte subset changes included a decrease in CD4:CD8 ratio and in the fraction of CD4+ T cells as well as an increase in NK cells, especially during the 400-msw bottom phase. An increased expression of hsp 27 compared to hsp 72/73 was obvious, especially during the hold period at 100 msw. These results suggest that changes in lymphocyte subsets and hsp expression are useful markers for stress responses during saturation diving. These changes may also be useful for testing the barotolerance of divers for saturation diving.

Biomarkers↗

PubMed1983

Lymphocyte subsets in Chediak-Higashi patients.

Peripheral blood lymphocyte subsets were studied in 6 Chediak-Higashi patients and 12 family members. The lymphocyte subsets were characterized by monoclonal antibody reagents and fluorescence flow-cytometry. An increase in OKT8 (suppressor/cytotoxic) and a decrease in OKT4 (helper) cell populations was observed in all patients studied. No correlation was seen between the clinical status (presence or absence of the lymphoproliferative phase) and the percentage of the lymphocyte subsets. The patient's mothers also had an increased percentage of OKT8-positive cells. The significance of these findings is discussed regarding the patients clinical course.

Adolescent↗

PubMed2004

Lymphocytes subsets in the course of continuous ambulatory peritoneal dialysis (CAPD).

BACKGROUND: We studied lymphocyte subset counts in comparison with normal subjects in order to clarify the abnormalities of cellular immune responses in uremic patients undergoing continuous ambulatory peritoneal dialysis (CAPD). METHODS: The study included 37 CAPD patients and 45 normal individuals, as the control group. For the study, CAPD patients were divided into four groups depending on duration of replacement therapy. Group I consisted of patients treated for 0-6 months (n=6), group II for 6-12 months (n=6), group III for 13-24 months (n=16), and group IV for more than 25 months (n=9). Flow cytometry was used for estimation of lymphocyte subsets (determination of CD2, CD3, CD3+/CD4+, CD3+/CD8+, CD3-/16+56+, CD19, CD4/CD8). RESULTS: Our patients started CAPD with decreased lymphocyte subset counts, slightly above the normal range (excluding CD3 -/16+56+, CD2). After 6 months of CAPD therapy, an increase in CD4/CD8 ratio was observed and all examined lymphocyte subset counts decreased (excluding CD2). In patients on CAPD for more than 25 months, CD3+/CD4+, CD19 counts were below the normal range, CD3 -/16+56+ exceeded the upper limit of normal range and at the same time mean total lymphocyte count (TLC) was maintained in the normal range. CONCLUSIONS: We recommend lymphocyte subset determinations for detection of immune abnormalities in the course of CAPD treatment.

Age Factors↗

PubMed2002

Age-related changes in lymphocyte subsets of quarter horse foals.

OBJECTIVE: To characterize changes in lymphocyte subsets over time in foals from birth to 18 weeks of age, accounting for differences among individuals, and to determine the effect of overnight storage of blood samples on foal lymphocyte subset concentrations. ANIMALS: 8 healthy Quarter Horse foals from birth to 18 weeks of age. PROCEDURE: Blood samples were collected longitudinally from birth to 18 weeks of age and a CBC performed on each sample. The samples were stained for lymphocyte markers, either immediately or after overnight storage and analyzed by flow cytometry. RESULTS: Total leukocytes, total lymphocytes, and the absolute concentrations of all lymphocyte subsets increased significantly with age. The proportions of B29A+, CD21+, and-equine major histocompatability complex class-II molecule+ lymphocytes increased significantly with age. The proportion of equine (Eq) CD5+, EqCD8+, and EqWC4+ lymphocytes decreased significantly with age. Significant differences among foals were found with respect to initial concentrations with respect to initial concentrations, but not with respect to the rate of increase of the various subsets tested. Significant differences were not found in subset values when comparing blood samples stained on the day of collection or after overnight storage at room temperature (approx 21 C) or under refrigeration. CONCLUSIONS AND CLINICAL RELEVANCE: These results are consistent with an increase in subset numbers and proportions over time, but with individual differences among foals. The observation of individual differences in subsets among foals suggests that there may be individual differences in susceptibility to infectious disease during the perinatal period. The absence of an effect of overnight storage makes field studies of lymphocyte subset concentrations more feasible.

Age Factors↗

PubMed1999

[Effect of immunologic treatment on lymphocyte subsets in patients with myasthenia gravis].

OBJECTIVE: To study the abnormalities of cellular immunity of myasthenia gravis (MG) and the effects of glucocorticoid (GC) therapy and thymectomy on lymphocyte subsets in patients with myasthenia gravis. METHODS: Phenotypic analysis of peripheral blood lymphocyte in 39 patients with MG and 18 healthy controls were completed using flow cytometry and immunofluorescence double-staining methods; changes of lymphocyte subsets were studied in 15 of the MG patients after GC therapy and 7 of the MG patients after thymectomy. RESULTS: (1) The percentage of pan-T (CD(+)(5)), pan-B (CD(+)(19)), traditional B cell, CD(+)(4)T cell in patients with MG did not significantly differ from that in healthy controls. An increase in CD(+)(8) cell was observed in MG patients as compared with normal controls. Among the CD(+)(4) T lymphocyte subsets, there was significant decrease of the percentage of CD(+)(4) CD(45)RA(+) (suppressor-inducer) and increase of the percentage of CD(+)(4) CD(45)RA(-) (helper-inducer) subsets in MG patients than controls; the percentage of CD(+)(5) B cell was significantly increased in MG patients as compared with that in healthy controls. (2) After GC therapy, the percentages of pan-T (CD(+)(5)), pan-B (CD(+)(19)), traditional B cell, CD(+)(4) T cell, CD(+)(8) T cell, CD(+)(4) CD(45)RA(-), CD(+)(5) B cell decreased. (3) After thymectomy, the proportions of T, B lymphocyte subsets did not change significantly. CONCLUSION: Not only changes of T cell subsets (CD(+)(4) and CD(+)(8) T lymphocyte subsets) were shown, but also there were abnormal changes of functional CD(+)(4) T lymphocyte subsets and CD(+)(5) B lymphocyte which may play an important role in the pathogenesis of MG. There is comprehensive inhibiting action of GC on cellular immunity in MG patients, while there is no such effect with thymectomy on the lymphocyte subsets in MG patients.

Adolescent↗

PubMed1989

Monoclonal antibody--defined lymphocyte subsets in normal Nigerians.

Lymphocyte subsets using monoclonal antibodies have hitherto not been reported in normal Nigerian subjects. In all 8 subjects, the average number of lymphocytes showed a clear rhythmicity with higher values in the morning (8 AM) than in the afternoon (2 PM). The time of day variation in circulating lymphocytes appears to affect T cells rather than B cells. The absolute numbers of OKT4+ cells at 8 AM was significantly higher than at 2 PM (p less than 0.05). It would appear that the OKT4+ cells are largely responsible for the time of day variation in peripheral blood lymphocytes, owing probably to a greater sensitivity to changes in plasma cortisol levels.

Adolescent↗

PubMed1993

Locomotor responses of human CD45 lymphocyte subsets: preferential locomotion of CD45RO+ lymphocytes in response to attractants and mitogens.

The CD45RO+ population of lymphocytes from human blood contains a higher proportion of locomotor cells than the CD45RA+ population. Direct from blood there were few locomotor lymphocytes (< 15%), but, among these, a higher proportion of CD45RO+ than of CD45RA+ cells responded to the chemotactic stimuli, foetal calf serum (FCS) and interleukin-2 (IL-2) in polarization assays. Likewise, after overnight culture, a higher proportion of CD45RO+ cells responded to IL-8. Culture for 24-72 hr in activators such as anti-CD3, purified protein derivative (PPD), phytohaemagglutinin (PHA), concanavalin A (Con A), pokeweed mitogen (PWM) or in an allogeneic mixed leucocyte reaction (AMLR) increased the proportion of locomotor lymphocytes to 20-60%, and the CD45RO+ subset showed proportionately more polarized cells than the CD45RA+ subset after culture with all the above activators. Preferential migration of CD45RO+ cells into collagen gels was also seen after culture in antigenic stimuli (PPD or AMLR) but not with polyclonal activators (alpha CD3 or Con A). Double labelling showed that, within the CD4+ and CD8+ subsets, antigen-stimulated CD45RO+ T cells invaded collagen gels in higher proportions than CD45RA+ T cells. Clustering of lymphocytes with accessory cells is an essential prerequisite for locomotion and, after culture in alpha CD3, CD45RO+ lymphocytes were found preferentially in clusters with monocytes. In all of the above populations, CD45RO+ lymphocytes were larger in size. These findings suggest that, not only selective adhesion to vascular endothelium as reported earlier, but also selective locomotion recruits CD45RO+ lymphocytes into sites of inflammation.

Cell Aggregation↗

PubMed1997

T-lymphocyte subsets in West African children: impact of age, sex, and season.

OBJECTIVE: There has been no reference material for T-lymphocyte subsets for normal children in developing countries. We therefore used T-lymphocyte subset determinations among children in three different studies in Guinea-Bissau to construct age-related reference material and to examine possible determinants of T-lymphocyte subset levels. METHODS: A total of 803 healthy West African children younger than 6 years were included in the three community studies of T-lymphocyte subsets among twins and singletons, after measles infection and after measles immunization. We used the immunoalkaline phosphatase method to determine T-lymphocyte subsets. RESULTS: We found differences by age, sex, and season, whereas there were no significant differences by birth order, twinning, or ethnic group. The CD4+ percentage declined from birth to age 2 years, at which time it started to increase to higher levels at age 4 to 5 years. The CD8+ percentage increased gradually from early infancy to age 2 to 4 years. The leukocyte count peaked at age 12 to 23 months and declined thereafter, whereas the lymphocyte percentage peaked at age 1 to 5 months and declined gradually thereafter. Compared with dry-season results, the lymphocyte percentage, the absolute lymphocyte count, the absolute CD4+ T-lymphocyte count, and the CD4+/CD8+ ratio were significantly lower during the rainy season, whereas the CD8+ percentage was increased during the rainy season. Girls had higher CD4+/CD8+ ratios and lower CD8+ percentages than did boys. CONCLUSIONS: Compared with the limited data on T-lymphocyte subsets available from healthy children in developed countries, Guinean children have markedly lower CD4+ percentages and CD4+/CD8+ ratios and higher lymphocyte percentages during the first 2 years of life, when the pressure of infections is particularly high in Africa.

Age Factors↗

PubMed1995

Analysis of leucocytes and lymphocyte subsets in cats with naturally-occurring cryptococcosis but differing feline immunodeficiency virus status.

Although cryptococcosis is a well-characterised disease of cats, the factors predisposing individuals to infection are unknown. As an indication of the immune status of an individual, lymphocyte subsets can be analysed. Reference ranges for feline lymphocyte subsets (Pan T+, CD4+, CD8+ and B cells) were established using a rapid whole blood technique and flow cytometry. There were no effects of age or sex on lymphocyte subset values. The numbers of circulating leucocytes and lymphocyte subsets were determined in FIV-positive and FIV-negative cats with cryptococcosis and compared with a group of healthy control cats. There were only minor differences in the numbers of lymphocyte subsets among the subgroups of cats examined in the study and the predisposition to cryptococcosis in cats could not be explained by deficiencies in lymphocyte subsets. There was a tendency for FIV-negative cats with cryptococcosis to have reduced numbers of circulating CD4+ cells and lower CD4:CD8 ratios compared with normal cats, although the interpretation of this finding was complicated by the wide reference range for normal cats. The extent to which this is the cause of the fungal infection was not determined. The only difference in leucocyte or lymphocytes subset values between FIV-negative cats with cryptococcosis and FIV-positive cats with cryptococcosis was that the CD4+ percentage was lower in the FIV-positive cats. The absolute CD4+ count was similar however, in FIV-positive and FIV-negative cryptococcosis cases. On the basis of this and other available information, the categorisation of cryptococcosis as a disease defining the AIDS phase of FIV infection may be incorrect.

Animals↗