Avaliação quantitativa do teste imunoenzimático ELISA no quadro clínico da infecção e diagnóstico do vírus Chikungunya

Abstract

Chikungunya virus infection causes an acute febrile disease and its diagnosis in Mozambique includes the detection of specific antibodies using the ELISA technique. In the ELISA test, the measurement of optical density is a quantitative indicator of the presence of immunoglobulin M (IgM) and immunoglobulin G (IgG). In samples positive for IgM and IgG anti-Chikungunya, the OD 450nm values ​​range from weak positive to strong positive (in relation to the cut-off), however, the impact of the variation in OD 450nm values ​​on the symptoms of the participants is unknown. Thus, the influence of optical densities on the clinical picture of Chikungunya virus infection in Mozambique was evaluated. Methodology: This is a longitudinal, retrospective study using the database of the ImmunoCHIKV study (2020-2021), carried out at the Coalane health center (Zambezia). The 450nm OD for IgM and IgG anti-Chikungunya were analyzed at 4 time points (0, 7, 21 and 60 days) and their relationship with signs and symptoms of participants. The influence of changes in OD 450nm on signs and symptoms was assessed using the Mann-Whitney U test and Spearman correlation, and the magnitude of the effect of significant variables was analyzed in the quantile regression model. Results: The optical densities of those positive for IgM in all visits were low [1.1 – 2.5] in relation to the optical densities for IgG [2.1 – 4.5] and, when analyzing the signs and symptoms, there was a reduction in the mean axial temperature from 37±0.09 o C to 36.71±0.11 o C for IgM and from 37.36±0.66 o C to 36.63±0.92 o C for IgG throughout visits 1 and 4. The common symptoms in those positive for Chikungunya in visit 1 were headache, arthralgia, weakness, chills, myalgia and anorexia, the frequency of which decreased throughout the visits. There was a statistically significant change in OD 450nm for IgM in relation to the symptoms of headache, retro-orbital pain and abdominal pain (p<0.05) and no symptoms stood out for IgG (p>0.05), however, in the quantile regression model the magnitude of the effect of these symptoms on the change in OD 450nm was not significant (p>0.05). Conclusion: The signs and symptoms were not directly influenced by the concentrations of IgM and IgG measured by the optical densities of the ELISA immunoenzymatic test, however, other factors may play an important role in the change in these values(TRADUÇÃO NOSSA)