Prevalence of neurological diseases among patients with selective IgA deficiency

Background: There are no published epidemiologic studies with regard to the prevalence of neurologic diseases among subjects with selective immunoglobulin A (IgA) deficiency (sIgAD). Objective: To investigate the prevalence of neurologic diseases among the Israeli population with sIgAD. Methods: A population-based case-control study among members of a large nationwide health maintenance organization in Israel providing services to > 700,000 members. The sIgAD group included individuals ≥4 years of age with a serum IgA level of <0.07 g/L and with a diagnosis of sIgAD. The control group was randomly sampled from the entire study population with a case-control ratio of five controls for each case (1:5), with exact matching for age, gender, ethnic group, and socioeconomic status category. Results: A total of 796 subjects ages 20.58 ± 15.46 years; 391 female subjects (49.1%) were identified as having sIgAD. The control group was constituted of 3980 matched subjects. The sIgAD group was characterized by a higher prevalence of autism spectrum disorder and tic disorders. Migraine was less prevalent in the sIgAD group (19 [2.39%]) than in the control group (168 [4.22%]), odds ratio (OR) 0.55 (95% confidence interval {CI}, 0.34-0.90); p = 0.016]. More cases of subjects with epilepsy were observed in the sIgAD group (14 [1.76%]) than in the control group (31 [0.80%]), OR 2.28 (95% CI, 1.12 - 4.44; p = 0.015). Conclusion: Our observation raises the question of the role of IgA in noninfectious diseases of the central nervous system. Further basic studies are needed to explain our observation.

Higher rates of allergies, autoimmune diseases and low-grade inflammation markers in treatment-resistant major depression

Only 30% of patients with major depressive disorder (MDD) reach full recovery or remission. Treatment-resistant depression (TRD) is MDD that does not respond to adequate treatment attempts with at least two antidepressants. TRD is associated more with immune activation than with treatment responsive depression. The current retrospective population-based cross-sectional study, utilizing data from a large nation-wide health maintenance organization in Israel which provides services to estimated 725,000 members, aimed to assess the clinical signs and laboratory markers of autoimmune comorbidity and low-grade inflammation, in patients with TRD. Included were participants aged 18-70 years, diagnosed twice within one year with ICD-9-CM MDD and two control groups, MDD responders (MDD-r) consisting of people with MDD and no TRD and a non-MDD group that included people with no MDD or TRD. The case (570 subjects in TRD group) to control ratio in both control groups (2850 subjects in MDD-r and 2850 subjects in non-MDD control group) was 1:5. Compared to MDD-r, the overall proportion of allergic diseases was higher among the TRD than among the MDD-r [OR 1.52 (1.19-1.94); p ​< ​0.001]. Any systemic autoimmune disease was associated with increased likelihood of MDD-r [OR 1.52 (1.04-2.24); p ​= ​0.03] or TRD [OR 2.22 (1.30-3.78); p ​= ​0.003]. Higher rates of positive (>1:80) antinuclear antibodies [33 (5.79%)] were found among the TRD than among the MDD-r [98 (3.44%); p ​= ​0.011). More allergy and autoimmune comorbidities and presence of low-grade inflammation biomarkers, were found mainly in TRD.