Systemic inflammatory responses following welding inhalation challenge test

Toxicology Repo s 2 (2015) 357–364 Con en s lis s a ailable a ScienceDi ec Toxicology Repo s jou nal homepage: www.else ie .com/loca e/ ox ep Sys emic inflamma o y esponses ollowing welding inhala ion challenge es Paula Kauppia,b,∗, Me ja Jä eläc, Timo Tuomic, Ri a Luukkonend, Tuula Lindholme, Riina Nieminen , Ee a Moilanen , Timo Hannub,g aUni e si y o Helsinki and Helsinki Uni e si y (Cen al) Hospi al, Respi a o y Diseases and Alle gology, Helsinki, Finland bOccupa ional Medicine, Finnish Ins i u e o Occupa ional Heal h, Helsinki, Finland cAe osols, Dus s and Me als, Finnish Ins i u e o Occupa ional Heal h, Helsinki, Finland dS a is ical Se ices, Finnish Ins i u e o Occupa ional Heal h, Helsinki, Finland ePhysical Wo k Capaci y, Finnish Ins i u e o Occupa ional Heal h, Helsinki, Finland The Immunopha macology Resea ch G oup, Uni e si y o Tampe e School o Medicine and Tampe e Uni e si y Hospi al, Tampe e, Finland gThe Hjel Ins i u e, Uni e si y o Helsinki, Helsinki, Finland a i c l e i n o A icle his o y: Recei ed 5 No embe 2014 Recei ed in e ised o m 18 Decembe 2014 Accep ed 23 Decembe 2014 A ailable online 2 Janua y 2015 Keywo ds: Cy okines Exposu e Mild s eel Occupa ional as hma S ainless s eel Welding Chemical compounds s udied in his a icle: Ch omium (PubMed CID: 23976) I on (PubMed CID: 23925) Manganese (PubMed CID: 23930) Nickel (PubMed CID: 935) a b s a c Aim: The aim o his s udy was o in es iga e inflamma o y and espi a o y esponses o welding ume exposu e in pa ien s wi h suspec ed occupa ional as hma. Me hods: Six een pa ien s e e ed o he Finnish Ins i u e o Occupa ional Heal h unde - wen mild s eel (MS) and s ainless s eel (SS) welding challenge es s, due o suspicion o OA. Pla ele coun , leucocy es and hei di e en ial coun , hemoglobin, sensi i e CRP, lipids, glucose and fib inogen we e analyzed in addi ion o in e leukin (IL)-1␤, IL-6, IL-8, TNF-␣, endo helin-1, and E-selec in in plasma samples. Peak expi a o y flow (PEF), o ced expi a- o y olume in 1 min (FEV1) and exhaled ni ic oxide (NO) measu emen s we e pe o med be o e and a e he challenge es . Pe sonal pa icle exposu e was assessed using IOM and a mini sample . Pa icle size dis ibu ion was measu ed by an Elec ic Low P essu e Impac o (ELPI). Resul s: The numbe o leukocy es, neu ophils, and pla ele s inc eased significan ly, and he hemoglobin le el and numbe o e y h ocy es dec eased significan ly a e bo h he MS and SS exposu e es s. Fi e o he pa ien s we e diagnosed wi h OA, and hei maximum all in FEV1 alues was 0.70 l (±0.32) 4 h a e SS exposu e. MS welding gene a ed an a e age inhalable pa icle mass concen a ion o 31.6, and SS welding o 40.2 mg/m3. The mean pa icle concen a ion measu ed inside he welding ace shields by he mini sample was 30.2 mg/m3and 41.7 mg/m3, espec i ely. Conclusions: Exposu e o MS and SS welding ume esul ed in a mild sys emic inflamma- o y esponse. The pa icle concen a ion om he b ea hing zones co ela ed wi h he measu emen s inside he welding ace shields. © 2015 The Au ho s. Published by Else ie I eland L d. This is an open access a icle unde he CC BY-NC-ND license (h p://c ea i ecommons.o g/licenses/by-nc-nd/4.0/). ∗Co esponding au ho a : Skin and Alle gy Hospi al, Helsinki Uni- e si y Cen al Hospi al, Meilahden ie 2, PO BOX 160, FI-00029 Helsinki, Finland. Tel.: +358 50 428 6802; ax: +358 9 471 86503. E-mail add ess: paula.kauppi@hus.fi (P. Kauppi). 1. In oduc ion Welding is a p ocess ha joins ma e ial, usually me als o alloys, by using hea and/o comp ession. Welde s a e exposed o umes con aining di e en gases and pa icles, depending on he composi ion o he welding elec odes, h p://dx.doi.o g/10.1016/j. ox ep.2014.12.015 2214-7500/© 2015 The Au ho s. Published by Else ie I eland L d. This is an open access a icle unde he CC BY-NC-ND license (h p://c ea i ecommons. o g/licenses/by-nc-nd/4.0/). 358 P. Kauppi e al. / Toxicology Repo s 2 (2015) 357–364 welded ma e ial, and he welding me hod used. Welding pa icles include bo h fine (0.1–2.5 ␮m) and ul afine pa - icles (< 0.1 ␮m) [1]. Welding ume exposu e has been associa ed wi h se e al ad e se heal h ou comes such as ch onic b on- chi is, pneumonia, me al ume e e , lung unc ion changes, and a possible ele a ed isk o lung cance and dea h om ischemic hea disease [2–8]. In addi- ion, popula ion-based s udies ha e shown ha welde s a e a an almos wo old isk o de eloping as hma [9,10]. Mo eo e , o he epidemiological s udies ha e indi- ca ed ha exposu e o welding umes may indeed be a di ec cause o as hma [11,12]. Some case se ies ha e e ealed occupa ional as hma (OA) in wo ke s exposed o s ainless s eel welding umes in pa icula [13–15]. The unde lying mechanisms esponsible o hese ca - dio espi a o y e ec s a e la gely unknown. One line o esea ch has in es iga ed he possible associa ion be ween welding ume exposu e and acu e sys emic inflamma- o y esponses [16–18]. The hypo hesis is ha sho - e m exposu e o welding umes may induce a local as well as sys emic inflamma o y eac ion, which may be espon- sible o ch onic lung and ca dio ascula disease i he exposu e pe sis s o a long ime [18]. In ou own ecen s udy [19], welding umes, as well as dus s and umes om shee me al wo k, caused a sligh acu e inflamma ion du ing a wo k shi in ac ual wo kplace con- di ions. The aim o he p esen s udy was o u he in es- iga e, on he basis o p io s udies, whe he sho exposu e o high concen a ion o welding umes is capa- ble o inducing acu e e ec s on hema ological, sys emic inflamma o y and espi a o y pa ame e s by ollow- ing welding challenge es in pa ien s wi h suspec ed OA. 2. Subjec s and me hods 2.1. S udy subjec s The s udy consis ed ini ially o 18 pa ien s who we e e e ed o he Finnish Ins i u e o Occupa ional Heal h (FIOH) by pulmonologis s o local cen al hospi als o by physicians o local occupa ional heal h uni s om all o e Finland in 2007. Six een o he pa ien s had been diag- nosed wi h as hma p e iously and wo pa ien s had as hma like symp oms bu no specific diagnosis o as hma; all pa ien s we e suspec ed o ha ing OA caused by welding umes. One pa ien was excluded om he s udy because his exposu e es s we e no pe o med on consecu i e days, and ano he was excluded because he was gi en medica- ion du ing he s udy which may ha e a ec ed he blood esul s. The e o e, he final s udy popula ion comp ised 16 pa icipan s. They we e all male, and wo ked as welde s (N = 7), shee me al wo ke s (N = 7), assemble s (N = 1) and me al wo ke s (N = 1). All o hem we e exposed o weld- ing umes in hei wo k ega dless o hei occupa ional i le. As hma medica ion was discon inued be o e es ing a FIOH. 2.2. S udy p o ocol Welding challenge es s we e pe o med in a special welding chambe (6 m3). Fi een o he pa icipan s we e exposed o mild s eel (MS) (con ol es ) and s ainless s eel (SS) welding umes on consecu i e days as desc ibed ea - lie o suspicion o OA [15]. One subjec was exposed o MS welding umes only. The manual me al a c welding (MMAW) exposu e ime was 30 min. Du ing he exposu e, fi e ods we e consumed in he MS con ol es (OK 48.00; ESAB AB, Go henbu g, Sweden) and 11 ods in he ST weld- ing es (OK 63.30; ESAB AB, Go henbu g, Sweden) [14]. OA was diagnosed acco ding o Eu opean guidelines [20]. S udy pa icipan s we e moni o ed o 24 h a e each challenge. Al oge he fi e enous blood samples (one blood sam- ple be o e each o he challenge es s and one blood sample a e each o he challenge es s and he fi h one on he nex day a e he es s) we e aken om each o he sub- jec s (Fig. 1). Baseline measu emen s o peak expi a o y flow (PEF), o ced expi a o y olume in 1 min (FEV1), and exhaled ni ic oxide (NO) we e pe o med be o e MS expo- su e, and hen app oxima ely 22 h a e he MS and SS exposu e. Each pa icipan ga e w i en in o med consen and filled in a ques ionnai e conce ning wo k and exposu e his o y, smoking habi s, lung and ca dio ascula disease his o y, and medica ion. The s udy p o ocol was app o ed by he E hics Commi ee o he Hospi al Dis ic o Helsinki and Uusimaa. 2.3. Hema ological and sys emic inflamma o y analyses The concen a ions o in e leukin (IL)-1␤, IL-6, IL-8, umo nec osis ac o alpha (TNF-␣), endo helin-1, and E-Selec in in he plasma samples we e de e mined by enzyme immunoassay (EIA) using comme cial eagen s: IL-1␤ (sensi i i y 0.063 pg/ml) and TNF-␣ (sensi i i y 0.125 pg/ml), Quan ikine HS ELISA, R&D Sys ems Eu ope L d., Abindgon, UK; IL-6 (sensi i i y 0.6 pg/ml), Peli- Pai ELISA, Sanquin, Ams e dam, he Ne he lands; IL-8 (sensi i i y 1.56 pg/ml), Op EIA, BD Biosciences, E em- bodegem, Belgium; endo helin-1 (sensi i i y 0.68 pg/ml), Quan iGlo ELISA, R&D Sys ems Eu ope L d., Abindgon, UK; E-Selec in (sensi i i y 20.5 pg/ml), ELISA, HyCul Bio ech- nology, Uden, he Ne he lands). Pla ele coun , leucocy es and hei di e en ial coun , hemoglobin, haema oc i , sensi i e C- eac i e p o ein (CRP), lipids, glucose, and le els o fib inogen we e ana- lyzed using es ablished me hods. All labo a o y analyses we e pe o med blind o he exposu e s a us o he s udied pa icipan s. 2.4. Respi a o y measu emen s A po able, pocke size spi ome e (One Flow, STI MED- ICAL, Sain -Romans, F ance) eco ded he lung unc ion measu emen s (PEF, FEV1), and a dec ease o 20% in PEF o FEV1 om he baseline alue was ega ded as significan [21]. Exhaled NO was measu ed using a chemiluminescence gas analyze (NIOX, Ae oc ine AB, Solna, Sweden), P. Kauppi e al. / Toxicology Repo s 2 (2015) 357–364 359 Fig. 1. Desc ip ion o s udy p o ocol. acco ding o ATS FENO guidelines. Values o >30 ppb we e conside ed o be o e no mal [22]. 2.5. Exposu e measu emen s Pa icle exposu e was assessed by pe sonal sampling om he b ea hing zone o 14 pa icipan s. Inhalable dus samples we e collec ed ou side welding ace shields using an IOM sample wi h a cellulose ace a e fil e (AAWP, diam- e e 25 mm; Millipo e, Bed o d, MA, USA). Sampling ime was 30 min and olume ic flow was adjus ed o 2.0 l/min. The samples we e analyzed g a ime ically [23]. In addi ion, mini sample measu emen s we e ca - ied ou simul aneously wi h he IOM sampling [24]. The mini samples we e collec ed om inside he welding ace shields o he 15 pa icipan s. The sampling olume ic flow was 0.75 l/min and he sampling ime 30 min. Dus samples we e analyzed g a ime ically. Du ing he MS and SS welding exposu e es s o h ee pa icipan s, pa icle numbe size dis ibu ions we e mea- su ed by an Elec ic Low P essu e Impac o (ELPI) (Deka i L d., Finland) in a size ange o 30 nm o 10 ␮m. The ELPI measu emen sys em gi es pa icula e numbe concen a- ions in 12 size bins co e ing he whole measu emen size ange. 2.6. S a is ical analyses Repea ed da a consis ed o he esul s o inflamma o y esponses du ing he exposu e in he welding chambe . All esponse a iables we e con inuous and mos ly no mally dis ibu ed. The e o e, he pai ed - es was applied when compa ing he alues be o e and a e a challange es . I he a iable was non-no mally dis ibu ed, he Wilcoxon one sample es was used. A P- alue o <0.05 was se o indi- ca e s a is ical significance. All analyses we e pe o med using he S a is ical Analysis Sys em, SAS Ve sion 9.1 (SAS Ins i u e Inc., Ca y, NC, USA). 3. Resul s 3.1. S udy popula ion cha ac e is ics The mean age o he 16 s udy pa icipan s was 44.6 ( ange 23–57 yea s), and hey we e all men (Table 1). A e age wo k his o y was 27.5 yea s o welding. One (6%) was a cu en smoke , eigh (50%) we e ex-smoke s, and se en (44%) had ne e smoked egula ly. Fou een o he pa ien s had been diagnosed wi h as hma p e i- ously and wo pa ien s had as hma like symp oms bu no specific diagnosis o as hma; h ee pa ien s had hype en- sion. The a e age se um choles e ol le el and plasma as- ing glucose le el we e high in he o al s udy g oup. As much as 75% (N = 12) had an ele a ed le el o o al se um choles e ol, 31% (N = 5) o iglyce ides and 19% (N = 3) o abno mal plasma as ing glucose le el. In addi ion, mean BMI (body mass index) was 27.5, showing mild o e - weigh . Table 1 Cha ac e is ics o pa icipan s (N = 16). Values o age, BMI, measu ed lab- o a o y es esul s, welding yea s, and exposu e gi en in means wi h s anda d de ia ion. Age, yea s 44.6 (10.7) BMI 27.5 (4.2) Baseline FEV1, l 3.7 (0.47) Baseline PEF, l/min 552 (92) Choles e ol, mmol/l 5.5 (1.0) HDL, mmol/l 1.3 (0.38) T iglyce ides, mg/l 1.6 (0.68) Glucose, mmol/l 5.7 (0.49) Diagnosed as hma 14/16 Welding, yea s 23.8 (13.0) Smoking habi s Cu en smoke s, N 1/16 Ex-smoke s, N 8/16 Non-smoke s, N 7/16 BMI: body mass index; FEV1: o ced expi a o y olume in 1 min; PEF: peak expi a o y flow; HDL: high densi y lipop o ein 360 P. Kauppi e al. / Toxicology Repo s 2 (2015) 357–364 3.2. Hema ological and sys emic inflamma o y ma ke s A e he MS exposu e es , hemoglobin le el dec eased significan ly om 157 g/l o 154 g/l and he numbe o e y h ocy es om 5.0 o 4.9 (1012 cells L−1), whe eas he numbe o leukocy es inc eased significan ly om 6.5 o 7.4 (109cells L−1), neu ophils om 3.7 o 4.4 (109cells L−1), and pla ele s om 273 o 291 (109cells L−1) (Table 2). Sim- ila s a is ically significan changes we e ound ollowing he SS exposu e es . O he sys emic immune pa ame e s, he concen a ion o E-selec in dec eased significan ly, bu only in he MS exposu e es ( om 48.7 o 46.2 ng/ml) (Table 2). 3.3. Respi a o y unc ion The base le el o exhaled ni ic oxide was ele a ed (>30 ppb) in fi e pa icipan s (31%). The e we e no s a is i- cally significan changes 22 h a e he welding exposu e es s (Table 3). Howe e , exhaled NO concen a ion inc eased by o e 30% in fi e s udy pa icipan s a e he MS exposu e es , and in wo pa icipan s a e he SS exposu e es compa ed o he base le el measu ed be o e he fi s exposu e es . The e we e sligh and s a is ically significan educ ions in he FEV1(mean FEV13.74 l in he baseline and 3.65 l a e MS (P 0.032) and 3.59 l (P 0.26) a e SS weld- ing) and PEF alues. Respec i ely, he mean PEF alue was 566 l/min a he baseline, 543 l/min a e MS (P 0.017) and 529 l/min (P 0.022) 22 h a e SS welding es s. Fi e pa icipan s had a posi i e eac ion (a dec ease o 20% o PEF o FEV1 om baseline alue) in he SS chal- lenge es and we e he e o e diagnosed wi h OA. In he es o he pa ien s (N = 11), he final diagnoses a e he examina ions a he FIOH we e as hma (N = 9), as hma like symp oms (N = 1) and ch onic obs uc i e pulmona y dis- ease (N = 1). In he pa ien s wi h OA (N = 5), he a e age FEV1 alue was 4.0 l (±0.38) and he PEF alue 617 l/min (±100) be o e he welding challenge es s. The maximum all in he FEV1and PEF alues was 0.70 l (±0.32) and 140 l/min (±62), espec i ely, 4 h a e SS exposu e. In pa - icipan s wi h no confi med OA (N = 11), leucocy es and neu ophils inc eased significan ly, whe eas e y h ocy es dec eased significan ly ollowing bo h he welding chal- lenge es s (Table 4). In pa icipan s wi h confi med OA, only pla ele coun inc eased significan ly, om 273 ± 76.5 o 288 ± 83.0 a e he MS exposu e es (P 0.014), and om 290 ± 81.9 o 304 ± 77.3 a e he SS exposu e es (P 0.014). 3.4. Pa icle exposu e Pa icle concen a ion measu ed in he b ea hing zone o 14 pa icipan s by he IOM sample a ied om 12.7 o 79.4 mg/m3in he MS and om 15.9 o 100 mg/m3in he SS exposu e es s. The a e age pa icle concen a ions we e 31.6 and 40.2 mg/m3, espec i ely. The mean pa icle con- cen a ion measu ed inside he welding ace shields by he mini sample was 30.2 mg/m3in he MS exposu e es s, and 41.7 mg/m3in he SS exposu e es s. Compa ed o he IOM esul s, he pa icle concen a ion measu ed by he mini sample was 4.4% lowe in he MS and 3.7% highe in SS exposu e es s. Fig. 2 p esen s he pa icle numbe size dis ibu ions in he MS and SS exposu es o one pa icipan . Pa icle size Table 2 Inflamma o y and hema ological pa ame e s be o e and a e welding exposu e es s. Blood pa ame e s Day 1, mild s eel exposu e MS (N = 16) Day 2, s ainless s eel exposu e SS (N = 15) Blood sample 5 Compa ison 5–1 Be o e A e P Be o e A e P Mean (±SD) P Hemoglobin, g/l 157 ± 12.8 154 ± 11.7 0.016 158 ± 12.0 155 ± 12.3 0.019 157 ± 11.3 n.s Leukocy es, 109cells L−1 6.5 ± 1.2 7.4 ± 1.5 0.009 6.7 ± 0.99 7.8 ± 1.6 0.004 6.7 ± 0.9 n.s. Neu ophils, 109cells L−1 3.7 ± 1.2 4.4 ± 1.3 0.002 3.8 ± 0.94 4.8 ± 1.4 0.004 3.9 ± 1.0 n.s. Lymphocy es, 109cells L−1 2.2 ± 0.66 2.2 ± 0.45 ns 2.3 ± 0.56 2.3 ± 0.46 ns 2.1 ± 0.64 n.s. Eosinophils, 109cells L−1 0.20 ± 0.09 0.16 ± 0.09 0.012 0.25 ± 0.09 0.20 ± 0.09 0.022 0.23 ± 0.11 0.025 E y ocy es, 1012 cells L−1 5.0 ± 0.38 4.9 ± 0.34 0.013 5.0 ± 0.34 4.9 ± 0.31 0.008 4.9 ± 0.32 n.s. Monocy es, 109cells L−1 0.40 ± 0.11 0.51 ± 0.15 0.012 0.38 ± 0.08 0.56 ± 0.20 <0.001 0.37 ± 0.13 n.s. Basophils, 109cells L−1 0.03 ± 0.05 0.06 ± 0.05 ns 0.04 ± 0.05 0.06 ± 0.05 ns 0.04 ± 0.05 n.s. Pla ele coun , 109cells L−1 273 ± 62.5 291 ± 61.3 <0.001 282 ± 57.3 293 ± 59.9 0.008 278 ± 52.4 n.s. Sensi i e CRP, mg/ml 1.46 + 2.24 1.51 + 2.25 ns 1.58 + 2.21 1.60 + 2.14 ns 1.46 ± 2.24 n.s. P-fib inogen, g/l 3.4 ± 0.98 3.1 ± 0.93 ns 3.4 ± 0.91 3.5 ± 1.1 ns 3.6 ± 1.01 n.s. IL-1␤, pg/ml 0.57 ± 0.43 0.45 ± 0.30 ns 0.65 ± 0.86 0.65 ± 0.76 ns 0.46 ± 0.30 n.s. IL-6, pg/ml 2.7 ± 1.6 2.5 ± 1.6 ns 2.5 ± 1.4 2.4 ± 1.1 ns 2.6 ± 1.4 n.s. IL-8, pg/ml 7.7 ± 2.8 7.2 ± 3.6 ns 8.3 ± 4.8 7.4 ± 2.7 ns 7.4 ± 3.3 n.s. TNF-␣, pg/ml 2.0 ± 0.68 2.0 ± 0.83 ns 2.1 ± 1.1 1.8 ± 0.53 ns 1.8 ± 0.6 n.s. Endo elin 1, pg/ml 0.92 ± 0.23 0.86 ± 0.22 ns 0.87 ± 0.21 0.88 ± 0.35 ns 0.90 ± 0.26 n.s. E-selec in, ng/ml 48.7 ± 20.9 46.2 ± 19.1 0.04 47.2 ± 19.2 47.3 ± 20.2 ns 45.9 ± 19.8 n.s. Compa ison 5–1: compa ison o Blood es 5 on Day 3, and o Blood es 1 on Day 1. P. Kauppi e al. / Toxicology Repo s 2 (2015) 357–364 361 Table 3 A e age exhaled ni ic oxide (NO), FEV1and PEF alues wi h s anda d de ia ion (SD) be o e and a e exposu e es s. Be o e exposu e es s (N = 16) A e mild s eel exposu e (N = 16) A e s ainless s eel exposu e (N = 15) Mean (SD) Range Mean (SD) Range Mean (SD) Range Exhaled NO, ppb 25 (22) 4.9–74 25 (24) 4.5–79 28 (27) 6.2–86 FEV1, l 3.74 (0.47) 3.65 (0.46) 3.59 (0.48) PEF, l/min 566 (92) 543 (79) 529 (87) FEV1: o ced expi a o y olume in 1 min; PEF: peak expi a o y flow. Table 4 Inflamma o y blood pa ame e s be o e and a e welding exposu e es s on pa icipan s wi h no confi med occupa ional as hma. Day 1, mild s eel exposu e (N = 11) Day 2, s ainless s eel exposu e (N = 10) Be o e A e P Be o e A e P Hemoglobin, g/l 159 ± 13.3 156 ± 11.6 0.031 159 ± 12.8 156 ± 13.8 ns Leukocy es, 109cells L−16.6 ± 1.4 7.5 ± 1.5 0.030 6.7 ± 0.81 8.2 ± 1.7 0.001 Neu ophils, 109cells L−13.4 ± 1.4 4.5 ± 1.4 0.003 3.7 ± 1.02 5.0 ± 1.7 0.002 Lymphocy es, 109cells L−12.4 ± 0.68 2.3 ± 0.37 ns 2.4 ± 0.48 2.4 ± 0.39 ns Eosinophils 109cells L−10.21 ± 0.09 0.17 ± 0.10 0.017 0.27 ± 0.10 0.23 ± 0.08 ns E y ocy es, 1012 cells L−15.1 ± 0.36 5.0 ± 0.31 0.013 5.1 ± 0.36 5.0 ± 0.33 0.024 Monocy es, 109cells L−10.41 ± 0.13 0.48 ± 0.13 0.030 0.37 ± 0.09 0.54 ± 0.19 0.010 Basophils, 109cells L−10.05 ± 0.05 0.06 ± 0.05 ns 0.05 ± 0.05 0.08 ± 0.04 ns Pla ele coun , 109cells L−1274 ± 59.4 292 ± 53.6 0.008 278 ± 46.8 288 ± 53.1 ns dis ibu ion was e y simila in bo h exposu es. To al pa i- cle numbe concen a ion in SS welding was 3.2 × 106cm−3 and in MS welding 1.7 × 106cm−3. SS welding gene a ed a highe pa icle numbe concen a ion, p esumably due o he highe od numbe consump ion han in MS weld- ing. In bo h exposu e es s, mos o he welding ume pa icles we e smalle han 1 ␮m. The middle poin o he mode was a ound 430 nm in bo h welding challenge es s. 4. Discussion Sys emic inflamma o y, hema ological and espi a o y esponses we e s udied in 16 middle-aged male wo ke s exposed o welding umes and o whom 14 had as hma, one ch onic obs uc i e pulmona y disease and one had as hma like symp oms. P e ious s udies on his subjec ha e been epidemiological [11,12,25,26], ca ied ou on heal hy ol- un ee s [16–18] o in wo kplace se ings [19,27]. This is Fig. 2. Pa icle numbe size dis ibu ion in one pa icipan ’s mild s eel (MS) and s ainless s eel (SS) exposu e es s. 362 P. Kauppi e al. / Toxicology Repo s 2 (2015) 357–364 he fi s s udy o epo he sys emic inflamma o y and hema ological esponses in pa ien s wi h as hma. Blood leukocy es and neu ophils inc eased signifi- can ly ollowing bo h he MS and he SS welding exposu e es s. This is consis en wi h o he s udies dealing wi h he acu e e ec s o welding exposu e [17–19]. Pe iphe al blood neu ophilia has also been ound ollowing sho - e m inhala ion exposu e o o he subs ances, such as ozone [28] and compos dus [29]. Blood pla ele s inc eased significan ly a e bo h he MS and SS welding challenges. This finding con adic s hose o Ha mann e al. [18] and hose we ou sel es ha e p e iously epo ed [19]. The ac ha hese p esen obse a ions could be seen as being a odds wi h hese p io findings migh also be due o di e ences in expo- su e cha ac e is ics. In he o me s udy, he pa icipan s we e exposed o umes o me al-ine -gas (MIG) weld- ing o aluminum and MIG solde ing o zinc-coa ed s eel and, in he la e s udy, o MS welding umes and o dus s and umes gene a ed om g inding MS pla es o pieces. In addi ion, he e was a en old di e ence be ween he a e age pa icle concen a ions in he ea - lie s udies and hose in he p esen s udy. Inc eased pla ele coun in pe iphe al blood has p e iously been epo ed as also occu ing a e inhala ion o diesel exhaus [30]. Ano he eason could be eac i e h ombocy osis due o inc eased inflamma ion o bone ma ow s imula- ion. Hemoglobin and e y h ocy e le els dec eased signifi- can ly ollowing bo h he MS and SS welding exposu e es s, which is consis en wi h ou ea lie findings [19]. Al hough his finding has no been obse ed in o he s udies dealing wi h he acu e e ec s o welding umes [17,18], a significan associa ion be ween he concen a- ion o pa icula e ma e (PM10) and blood hemoglobin le els has been epo ed by Sea on e al. [31]. I is unclea how fine pa icula e ma e exposu e leads o changes in hemoglobin o e y h ocy e le els, bu i has been specu- la ed ha his could be due o a combina ion o mechanisms such as olume s a us o s ess, which could a ec blood iscosi y [30]. As a possible mechanism, Sea on e al. sug- ges ed ha he inhala ion o some componen o PM10 may cause he seques a ion o ed cells in ci cula ion [31]. In ou p io s udy, he dec ease in hemoglobin le - els may ha e been caused by di e ences in me abolic in ensi y and fluid shi s du ing mode a e- o low-le el physical wo k [19]. Ou p esen esul s could also be influ- enced by hese ac o s, al hough he welding was no as physically demanding as welding in ac ual wo kplace con- di ions. Taken oge he , ou pe iphe al blood findings ( he inc eased le el o blood leukocy es, neu ophils, and pla ele s, and he dec eased le el o hemoglobin and e y h- ocy es) a e in line wi h he sugges ion ha a mild sys emic inflamma o y esponse akes place du ing welding expo- su e [16,17,19]. This esponse was a ime-limi ed p ocess, because 22 h a e he las exposu e es , he esponse was a enua ed. The p esen s udy obse ed no s a is ical di e ences in CRP le els, which is in acco dance wi h ou ea lie esul s [19]. In gene al, he a ailable da a on his subjec is mixed, since some o he s udies suppo significan CRP changes ela ed o welding ume exposu e [17,29] while o he s do no [16,19]. This inconclusi e si ua ion demands u he in es iga ion. No s a is ical di e ences in he concen a- ions o acu e-phase media o s such as TNF-␣, IL-6 and IL-8 ha e been epo ed in humans ollowing welding exposu e [16,19]. We also ound no s a is ical di e ences in he le - els o hese cy okines, and he e o e, ou cu en findings confi m p e ious obse a ions. The le els o IL-1␤, which is a p oinflamma o y cy okine, in ela ion o welding ha e hus a only been s udied once [19]. The s udy ound ha IL-1␤ le els dec eased significan ly, which was unexpec ed. In he p esen s udy, no significan changes we e obse ed in IL- 1␤ le els. E-selec in le els in ela ion o welding ha e also only been s udied once o da e [18]. In ou p e ious s udy, he E-selec in le el dec eased significan ly, which was also obse ed in he p esen s udy, bu only ollowing expo- su e o he MS welding umes. We also s udied he le els o endo helin-1, which is a asocons ic o pep ide, and fib inogen, which is a soluble plasmap o ein, bu ound no significan changes in ei he , which is in acco dance wi h p e ious epo s [16,18,19]. Exposu e o welding umes has been associa ed wi h educed pulmona y unc ion [25–27] and as hma [9,10,11]. I has been sugges ed ha changes in welde s’ lung unc- ions a e ansien , occu ing a he ime o exposu e a he wo kplace and e u ning o no mal du ing non-exposed pe iods. Welding umes o s ainless s eel can cause OA [13,15]. In his s udy we ound fi e cases o OA, and hese indi iduals showed ma ked la e phase changes in pulmona y unc ion (FEV1, PEF) in esponse o he SS welding challenge es . In e es ingly, significan changes in hema ological pa ame e s we e ound in non-occupa ional as hma pa ien s bu no in pa ien s wi h confi med OA. Behndig e al. epo ed pa allel findings in hei s udy, in which bo h as hma pa ien s and heal hy indi iduals we e exposed o diesel exhaus pa icles o fil e ed ai . They obse ed a significan inc ease o submucosal neu- ophils and o neu ophil numbe s in he b onchial wash o he heal hy pa icipan s bu no among he as hma ics [32]. SS welding gene a ed a highe pa icle mass and num- be concen a ion, p esumably due o he highe od numbe consump ion han ha in MS welding. In bo h exposu e es s, mos o he welding ume pa icles we e smalle han 1 ␮m, and he pa icle size dis ibu ion was simila in bo h exposu es. The a e age welding ume exposu e in challenge es s was high, bu simila high momen a y exposu es can also occu in wo kplace condi- ions. The measu ed pa icle mass ange was qui e wide, depending mos ly on he pa icipan ’s wo king me hod. Some pa icipan s we e ben e y close o he objec being welded, he e o e hei b ea hing zone pa icle concen- a ions we e highe han hose o he pa icipan s who we e a a longe wo king dis ance om he objec being welded. The umes gene a ed du ing mild s eel weld- ing con ain mainly i on (80–95%) and also manganese (1–15%), whe eas s ainless s eel welding p oduces smalle amoun s o hese bu high amoun s o ch omium (15–30%) and nickel (5–10%) [4]. We did no de e mine he me al P. Kauppi e al. / Toxicology Repo s 2 (2015) 357–364 363 composi ion o he umes gene a ed in he challenge es s in he p esen se ies, bu we ha e done his p e iously [33]. These published esul s a e in line wi h hose published in he li e a u e. The s eng h o ou s udy was he possibili y o objec i ely moni o bo h he welding exposu e and he inflamma o y, hema ological and espi a o y esponses a he indi idual le el. The limi a ions o he s udy we e he lack o an unexposed con ol g oup and he ela i ely small numbe o pa icipan s. Since he welding challenge es s in he labo a o y en i onmen we e he only p ocedu es wi h he s udy indi iduals du ing he days, he e is no o he explana ion o he sligh inflamma o y esponse e en in he lack o unexposed con ol g oup. The s udy pa icipan s s ayed a he FIOH du ing he es days and hus wo k, exe cise, o o he en i onmen al ac o s can- no be used as an explana ion. Also, he esul s a e in line wi h ou p e ious s udy on welding in an occupa- ional/wo kplace se ing [19]. Fu he mo e, a la ge s udy g oup would p obably ha e gi en mo e significan esul s, a he han diminish he findings. The p esence o C and Ni in he umes may cause lung inju y and inflamma ion, lung umo o ma ion, immune dys unc ion, and sys emic oxici y [34]. Howe e , welding p ocesses p oduce umes consis ing o gaseous and ae osol by-p oduc s composed o me als, me al oxides and ola ilized chemical species om he base me als, welding elec ode, o flux ma e ial [1]. In he p esen s udy, we could no elucida e which compo- nen o he welding umes was esponsible o he obse ed findings. We canno exclude ha pe o ming he exposu e es s on consecu i e days could ha e a ec ed he esul s. Un o - una ely, he e is no wo ldwide consensus how welding exposu e es s should be pe o med. Howe e , he si u- a ion could be be e in he u u e, because sugges ions ha e been published how expe imen al welding ume exposu e s udies unde con olled and s anda dized con- di ions should be ca ied ou ([35]). The used welding challenge es s in ou se ies ha e been s anda dized [15]. The challenge es s a e he “golden s anda d” o diag- nosing OA. The p ocedu e includes fi s he placebo es and he ac i e es second. I is impo an ha he ime be ween he wo es s should be minimized since he pa ien s cease hei as hma medica ion, and he longe he pe iod be ween he wo es s is he less compa able he es esul s a e. Fu he mo e, keeping an as hma pa ien wi hou egula as hma medica ion o se e al days would p o oke unspecific as hma symp oms and alse posi i e es esul s. 4.1. Conclusions In conclusion, we obse ed a mild sys emic inflamma- o y esponse ollowing welding ume challenge es s. An inc ease was obse ed in pe iphe al blood leukocy es, neu- ophils, and pla ele s, and a dec ease in hemoglobin le el and in e y h ocy e coun . 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