A total of 156 consecutive HIV-positive patients were enrolled in the study between January 2016 and September 2017. Demographic and clinical data of the study population are described in Table 1. The majority of subjects were males (75%), mean age was 47.05 ± 12.38 (range 22 to 71 years), 39 participants (25%) were coming from non-EU countries and 50 ones (32%) were MSM (men who have sex with men). Moreover 47.4% were owner of pets and 42.9% travelled outside Europe in the last 6 months.
Twenty-three patients (14.7%) were naïve and 133 (85.3%) were on ART treatment. Thirty-five subjects (26.3%) were on ART based on non-nucleoside reverse-transcriptase inhibitors (NNRTI), 34 (25.6%) on protease inhibitors (PI/r), 36 (27.1%) on integrase inhibitors and 28 (21%) on dual therapy. Three of the enrolled patients were on prophylaxis treatment with sulfamethoxazol-trimethoprim. The mean CD4 cell count was 655.04 ± 381.56 cells/mm3. Most of patients (62.2%) showed a CD4 count higher than 500 cells/ml, 26.3% patients had a CD4 count between 200 and 500 cells/ml and only 11.5% patients showed a CD4 count lower than 200 cells/ml. The median HIV-RNA level of naive patients was 40010 (7093-824500) -copies/mL. Among patients on ART treatment, HIV-RNA was detectable (>37 cp/mL) in 15.8% of subjects (21/133) with a median HIV-RNA level of 116 (67-991) cp/mL.
Study population
|
N (%)
|
Gender, male
|
117 (75%)
|
Age, years (mean ± SD)
|
47.05 ± 12.38
|
Foreign origin
|
39 (25%)
|
MSM
|
50 (32.0%)
|
Domestic animals
|
74 (47.4%)
|
Travels
|
67 (42.9%)
|
CD4 count, cells/ml, mean ± SD
|
655.04 ± 381.56
|
HIV-RNA (<37 copies/ml)
|
112 (71.8%)
|
Naïve subjects
|
23 (14.74%)
|
2NRTI + NNRTI
|
35 (26.3%)
|
2NRTI + IP/r
|
34 (25.6%)
|
2NRTI + INI
|
36 (27.1%)
|
Dual therapy
|
28 (21%)
|
Table 1. Epidemiological, demographic, immunologic and virological characteristics of the enrolled patients (N=156). A total of N=23 were naïve and N=133 on ART.
Microscopic examination revealed the presence of Blastocystis spp. in 34 patients (21.8%). Molecular and sequence analysis identified the protist in 39 individuals (25%), allowing the characterization of 4 different STs. ST3 was the most common subtype found in 51.3% of the subjects, followed by ST1 (30.8%), ST4 (10.2%) and ST2 (7.7%). As expected, ST4 was identified only in European participants. In 30.7% of the subjects, Blastocystis was found in coinfection with other enteric protozoa as Entamoeba coli (15%), Endolimax nana (8%), Giardia intestinalis (6.1%) and Iodamoeba butschlii (1.6%). The detection of such intestinal parasites was more frequent in Blastocystis-carriers compared to Blastocystis-free ones (p<0.0001) and in MSM compared to heterosexual subjects (p<0.0001).
Neither demographic characteristics such as gender, age and nationality nor other epidemiological risk factors such as travel history or, presence of domestic animals differed significantly between the Blastocystis positive and Blastocystis negative patients (Table 2). In addition, no significant differences were found between the two groups regarding CD4 T cell counts, HIV-RNA undetectability and type of ART regiment. Blastocystis positive subjects reported more frequently homosexual behavior practices compared to negative ones (48.71% vs 26.49%, p=0.037). After adjusting for age, the relationship between homosexual behavior practices and the presence of Blastocystis remained significant (p=0.01).
|
Blastocystis-carriers
N(%)
|
Blastocystis-free
N(%)
|
p-value
|
Gender, male
|
33 (82.0%)
|
84 (72.6%)
|
0.289
|
Age, years (mean ± SD)
|
44.71 ± 11.33
|
47.05 ± 12.37
|
0.06
|
Foreign origin
|
15 (38.46%)
|
25 (21.36%)
|
0.138
|
MSM
Domestic animals
Travels
|
19 (48.71%)
18 (46.15%)
20 (51.28%)
|
31 (26.49%)
56 (47.86%)
47 (40.17%)
|
0.037*
0.721
0.296
|
CD4 count, cells/ml, mean ± SD
|
637.43± 263.32
|
660.90± 414.35
|
0.823
|
CD4 count > 500 cells/ml
CD4 count 200– 500 cells/ml
CD4 count <200 cells/ml
|
28 (71.79%)
8 (20.51%)
3 (7.69%)
|
69 (58.97%)
33 (28.20%)
15 (12.82%)
|
0.484
|
HIV-RNA (<37 copies/ml)
|
32 (82.05%)
|
80 (68.37%)
|
0.257
|
Naïve subjects
2NRTI + NNRTI
2NRTI + IP/r
2NRTI + INI
Dual therapy
|
5 (12.82%)
9 (23.07%)
7 (17.94%)
12 (30.76%)
6 (15.38%)
|
18 (15.38%)
26 (22.22%)
27 (23.07%)
24 (20.51%)
22 (18.80%)
|
0.765
|
Table 2. Comparison of epidemiological, demographic, immunologic and virological characteristics between Blastocystis- carrier (N=39) and Blastocystis-free (N=117) patients. Significant results were marked with *.
Most of the Blastocystis positive subjects were symptomatic (53.8%), while 33.6% Blastocystis-free ones referred gastrointestinal disorders (p=0.029). Among the gastrointestinal symptoms analyzed, flatulence was more frequently observed in Blastocystis carriers (30.7%) compared to Blastocystis negative ones (14.5%) (p=0.024) (Table 3).
Symptoms
|
Blastocystis-carriers
N(%)
|
Blastocystis-free
N(%)
|
p-value
|
Abdominal pain
|
7 (17.94%)
|
26 (22.22%)
|
0.836
|
Diarrhoea
|
10 (25.64%)
|
20 (17.09%)
|
0.283
|
Flatulence
|
12 (30.76%)
|
17 (14.52%)
|
0.024*
|
Nausea
|
3 (7.69%)
|
6 (5.12%)
|
0.887
|
Poor appetite
|
5 (12.82%)
|
10 (8.54%)
|
0.180
|
Weight loss
|
3 (7.69%)
|
10 (8.54%)
|
0.658
|
Table 3. Gastrointestinal symptoms observed in Blastocystis- carrier (N=39) and Blastocystis-free (N=117) patients. Significant results were marked with *.
To determine whether Blastocystis colonization was associated with intestinal inflammation (as inferred by the Rome III criteria questionnaires), we measured FC in a subset of samples divided in Blastocystis-carrier (mono-infected) (N=23) and Blastocystis-free (N=36) subjects rom the all 59 fecal samples (Blastocystis-carrier and Blastocystis-free), 83% had a value in the standard range (lower than 50 mg/kg) and 11 (18.6%) had an increased value (median 115.7; 95% CI=71.82-303.78). However, no significant differences in calprotectin values was found between Blastocystis-carriers (median 15, 95% CI= 18.93-148.53) and non-carriers (median 13.35, 13.93-31.74) (p=0.31).