Urinary Histamine levels in patients with acute dengue
A study carried out in a small cohort of patients, who had severe dengue
showed that 24-hour urine histamine was higher in patients with DHF
compared to healthy individuals (Syenina A et al., 2015). Therefore, in
order to understand the possible role of histamine in disease
pathogenesis, we determined the urinary histamine levels in patients
recruited ≤ 4 days of illness (n=91), between 5 to 6 days of illness
(n=37) and 29 healthy individuals. Of the 91 patients recruited ≤ 4 days
of illness, 52 had DF and 39 had DHF. In comparison to healthy
individuals (median 0.22, IQR 0.07–0.76ng/mg creatinine), patients with
DF (median 2.92, IQR 0.53–7.83ng/mg creatinine,) and those who
proceeded to develop DHF (median 5.4, IQR 1.10-5.4ng/mg creatinine, p= ˂
0.0001) had significantly higher levels of urinary histamine
(p<0.0001) (Fig 6a) . Although patients with DHF had
higher levels of urinary histamine compared to patients with DF it was
not statistically significant (p=0.31) (Fig 6a) . Although the
urinary histamine levels were lower during day 5 to 6 in patients with
DF (median 0.15, IQR 0.06 – 0.86ng/mg creatinine, p= 0.80) compared to
healthy individuals, the histamine levels of those with DHF was still
high (median 0.29, IQR 0.05 – 1.12ng/mg creatinine). (Fig 6a) .
There was no significant difference in urinary histamine levels in
patients with primary and secondary dengue (Fig 6b) and there
was no relationship with the viral loads (Fig 6c) . The urinary
histamine levels did not significantly correlate with urinary LTE4
levels in patients with DF (Spearman r = -0.08335, p = 0.56) or DHF
(Spearman r = -0.2446, p= 0.13) (Fig 6d) .