結膜炎の抗クラミジア特異抗体の検討

Specific antibodies to Chlamydia trachomatis in conjunctivitis

　クラミジア感染の判定には，血清抗体の検出が最も感度が高い．クラミジア病原体の分離培養や抗原の検出は，種々の条件を満足しなければ陽性と出ず，たとえ陰性であってもクラミジア感染を否定できない．このため疫学的調査には，血清抗体の検出がきわめて優れている．

　感染症の特異抗体としてのIgG,IgM,IgAのうち，IgMはクラミジア眼感染症においては一般に陰性であり，診断的意義は低い．しかしIgG,IgA抗体価自体と時間的推移など条件を決めて利用すれば，その診断的応用も可能である．

　正常者とトラコーマ瘢痕期の患者群を対照として，クラミジア分離と抗原の検出と共に結膜炎患者のクラミジア特異抗体の検討を行い，単一血清抗体の診断条件をIgG 0.71（ELISA），160倍（FA），64倍（I-PA），IgAは16倍（I-PA）とした．なお血清採取が容易でない新生児や乳幼児では，涙液中のIgG （ELISA）が0.17以上では意義がある．

We evaluated IgA and IgG antibodies for Chlamydia trachomatis in serum samples from 218 patients with conjunctivitis. Chlamydia trachomatis was isolated in 49 patients and was negative 121. Typical findings of cicatricial trachoma, stages IV, was present in 38. An additional series of 59 normal subjects served as control.

The serological analysis was conducted by microimmunofluorescence test (FA), enzyme-lin-ked immunoassay (ELISA) and indirect inclusion immunoperoxidase assay (I-PA). The findings were correlated against cell culture findings for C. trachomatis.

We set the diagnostic criteria of serum antibody to C. trachomatis as 0.71 for ELISA, 160x for FA, 64x and 16x for IgG and IgA each by I-PA. Through I-PA, IgA specific for C. trachomatis was found in 21/57 cases (37%) in acute conjunc-tivitis and in none in cases with cicatricial tra-choma. This finding seemed to characterize the IgA titer as an index of chlamydial inflammation activ-ity.

IgG antibody specific for C. trachomatis was higher in patients with culture-positive conjunc-tivitis 32/49 (65%) and with trachoma 32/38 (84%) than is those with culture-negative conjunctivitis 40/121 (33%) and in control 12/59 (20%). The difference was significant.

Rinsho Ganka (Jpn J Clin Ophthalmol) 42(1) : 39-42, 1988