Significance of anti-Chlamydophila pneumoniae IgA and IgG determination in patients with acute and post-acute ischaemic stroke

Objectives: Accumulating evidence indicates that recent acute infections and chronic infectious diseases are important triggers or risk factors for ischemic stroke (IS) mediated by atherogenic process in the arteries. Chlamydophila pneumoniae (Cp) has been associated with first IS by enhancing atherosclerosis. Serological data however are limited and results often contradictory. We aimed to investigate the seroprevalence of C. pneumoniae antibodies in patients with acute IS and its impact on admission and follow-up. Methods: We evaluated in a retrospective case-control study performed between January 2007 and October 2011 anti-Cp IgA and IgG (B.U/ml) serum samples from 78 consecutive patients (mean age, 66.7, range 35-82 yr) with first IS at different times (admission, 0-9 h), 7 and 90 days after, in relation to age, sex, NIHSS score (mean values on admission vs 90 days after), CT scan and stroke subtype (TOAST). Results: Anti-Cp IgA have shown statistically significant values in 53.8% (42/78) IS patients vs 10.5% (9/85) age and sex matched controls (p<0.021), compared to Cp IgG (71.7%, 61/78) vs 84%, (72/85); p<0.38). IgA titres were evaluated according to the following score: low (10 to 30), intermediate (30 to 60), elevated (>60), more elevated (>90). Of IS patients, 12 (15.3%) had intermediate IgA titres on admission which became more elevated 90 days after (Group 1; NIHSS, 10 vs 4.08, p<0.022); 10 (12.2 %) had more elevated IgA titres on admission but decreased at 90 days (Group 2; NIHSS, 10.7 vs 4.4, p<0,063); 6 (7.6 %) had intermediate IgA titres on admission but low 90 days after (Group 3; NIHSS, 11 vs 5.2, p<0.091); 4 (5%) had low/intermediate titres on admission but increased at 90 days (Group 4; NIHSS, 7.3 vs 1.7, p<0.014); 6 (7.6%) had negative IgA titres on admission that slightly increased at 7 and 90 days (Group 5; NIHSS, 11 vs 1.2, p=0,000053); 4 (5%) patients had low titres on admission and intermediate at 7 days but was negative 90 days after (Group 6, NIHSS,12.3 vs 5.5, p<0.274). All patients showed intermediate Cp IgG titres from admission to 90 days. Conclusions: Patients from Group 1, 4 and 5 showed a NIHSS score statistically significant after 90 days. Positive or negative IgA values at IS onset which increase and become elevated at 90 days, appear to be associated with clinical and neuroradiological improvement. No significant statistical difference in achieving of good outcome was seen between IgA in relation to age, sex or TOAST.