Koshy Maria, Mathew John, Alex Reginald, Jude John Antony, Ralph Ravikar, Sudarsanam Thambu David, Sathyendra Sowmya, Visalakshi J, Peter John Victor
Department of Medicine, Christian Medical College & Vellore, India.
Department of Rheumatology, Christian Medical College & Vellore, India.
J Vector Borne Dis. 2018 Jan-Mar;55(1):52-57. doi: 10.4103/0972-9062.234627.
BACKGROUND & OBJECTIVES: The pathological hallmark of scrub typhus infection is focal or disseminated vasculitis. As with other infections, antinuclear antibodies (ANA) have been previously described in scrub typhus. However, the underlying mechanisms and implications of this immunological phenomenon is not well understood. In the present work it was assessed whether ANA is associated with illness severity and outcomes.
In this prospective study spanning one year, patients fulfilling the diagnostic criteria for scrub typhus were recruited. Patients with other acute infective febrile illnesses were taken as controls. ANA positivity was compared between the cases and controls. ANA in scrub typhus was assessed for correlation with disease severity, organ dysfunction and outcomes.
The cohort comprised of 149 patients (scrub 89; controls 60) with mean age 46.5 (SD=16.9) yr; 48.3% were female. ANA was detected in 48 (53.9%) patients with scrub typhus and 9(15%) controls (p < 0.001). The ANA pattern was predominantly speckled (93.8%) in both scrub typhus patients and controls. In patients with scrub typhus, ANA positivity was associated with increasing APACHE-III score [Odds ratio (OR) 1.01; 95% CI 0.99-1.03; p = 0.09]. On bivariate analysis, ANA tended to be correlated with acute respiratory distress syndrome (OR 2.32; 95% CI 0.98-5.46; p = 0.06), hepatic dysfunction (OR 2.25; 95% CI 0.94-5.39, p = 0.06) and aseptic meningitis (OR 6.83; 95% CI 0.80-58.05, p = 0.08). The presence of these antibodies did not correlate with duration of hospitalization or mortality. Convalescent sera on 31 ANA positive scrub typhus patients demonstrated persistence of ANA in only 5 (16.1%) patients.
INTERPRETATION & CONCLUSION: The disappearance of ANA during the convalescent phase suggests that ANA is expressed during the acute phase of scrub typhus infection. Its association with organ dysfunction warrants further study of the mechanisms and impact of autoantibody formation in scrub typhus.
恙虫病感染的病理特征是局灶性或播散性血管炎。与其他感染一样，先前曾在恙虫病中描述过抗核抗体（ANA）。然而，这种免疫现象的潜在机制和影响尚未完全了解。在本研究中，评估了ANA是否与疾病严重程度和预后相关。
在这项为期一年的前瞻性研究中，招募了符合恙虫病诊断标准的患者。将患有其他急性感染性发热疾病的患者作为对照。比较病例组和对照组中ANA的阳性率。评估恙虫病患者的ANA与疾病严重程度、器官功能障碍和预后的相关性。
该队列包括149名患者（恙虫病组89例；对照组60例），平均年龄46.5岁（标准差=16.9岁）；48.3%为女性。48例（53.9%）恙虫病患者检测到ANA，9例（15%）对照检测到ANA（p<0.001）。恙虫病患者和对照组中ANA模式主要为斑点型（93.8%）。在恙虫病患者中，ANA阳性与APACHE-III评分增加相关[比值比（OR）1.01；95%置信区间0.99-1.03；p=0.09]。在二元分析中，ANA倾向于与急性呼吸窘迫综合征（OR 2.32；95%置信区间0.98-5.46；p=0.06）、肝功能障碍（OR 2.25；95%置信区间0.94-5.39，p=0.06）和无菌性脑膜炎（OR 6.83；95%置信区间0.80-58.05，p=0.08）相关。这些抗体的存在与住院时间或死亡率无关。对31例ANA阳性恙虫病患者的恢复期血清检测显示，仅5例（16.1%）患者的ANA持续存在。
恢复期ANA消失表明ANA在恙虫病感染急性期表达。其与器官功能障碍的关联值得进一步研究恙虫病中自身抗体形成的机制和影响。
