HLA-DRB1*01 allele and low plasma immunoglobulin G1 concentration may predispose to herpes-associated recurrent lymphocytic meningitis.

Recurrent lymphocytic meningitis (RLM) is a rare illness caused mostly by herpes simplex virus type 2 (HSV-2). Predisposing factors are not known. Deficiencies in immunoglobulin (Ig) G subclasses 1 (IgG1) and 3 (IgG3) and complement protein C4 are associated with susceptibility to and persistence of bacterial and viral infections. Selected HLA and mannose-binding lectin (MBL) alleles have previously been associated with recurrent genital herpes or herpetic meningitis. We assessed the frequencies of low IgG1 and IgG3, their allotypes (Gm), and HLA-A*, -B*, -DRB1*, and MBL2 alleles, as well as deficiencies in C4A and C4B genes, as potential predisposing factors for HSV-2-associated RLM. The level of IgG1 was lower (p = 0.009) and the frequency of low IgG1 was higher (p < 0.001) in patients than in controls. Furthermore, the risk for a new meningitis episode was increased in patients with low IgG1 (incident ratio 2.05). HLA-DRB1*01 (p = 0.009) and -B*27 (p = 0.050) were more common among patients than controls. We conclude that HLA-DRB1*01 and -B*27 alleles and low plasma IgG1 levels may be significant risk factors for RLM.